ABS Class Notations Explained: A Complete Guide (March 2025 Edition)

Introduction: reading a ship’s class line

A class notation is a short code on a ship’s classification certificate that states what the vessel was built, equipped or approved to do. The American Bureau of Shipping (ABS) publishes the full list as ABS Notations and Symbols; this guide walks through the March 2025 edition, notation by notation.

Each notation records compliance with a specific ABS Rule or Guide. Some are mandatory: the vessel must meet them to receive and keep its class certificate. Others are optional and can be added or dropped without affecting the validity of class. Some assignments also need acceptance by the ABS Class Committee.

A typical class line shows how they combine. For a tug it can read: ✠A1, Towing Vessel, Ⓔ, ✠AMS, QR, BP(60MT). The first symbols confirm hull and machinery built under ABS survey, the vessel type follows, then the equipment and capability notations.

How this guide is organised

• Common notations and symbols apply to almost any vessel or offshore unit: hull structure, machinery, automation, surveys, fuels, safety and environment.
• Vessel-type notations follow, grouped as ABS groups them: cargo ships, steel vessels under 90 m, offshore support vessels, naval ships, high-speed craft, light warships, yachts, barges, river craft, underwater vehicles and offshore installations.
• Bold names are the notations as written by ABS. The line after each name says what it signifies, in plain words.
• In this text, ✠ stands for the Maltese Cross symbol and Ⓔ for the Circle E symbol.

Common notations, part 1: core symbols, machinery, power and cyber

These first notations apply to almost every ABS-classed vessel. They cover the basic class symbols, machinery and automation, alternative power, ballast water, low-temperature operation, cranes, cybersecurity and dynamic positioning.

• ✠ Maltese Cross — Shows that hull construction and/or machinery manufacture, with the required testing, was carried out under ABS survey. If another recognised society surveyed the build, the cross is left off.
• ✠A1 — The core hull symbol. With the cross, it confirms the hull meets ABS requirements for unrestricted ocean service and was surveyed by ABS during construction. A vessel-type notation (Oil Carrier, Bulk Carrier, Passenger Vessel and so on) follows it.
• Ⓔ Circle E — Confirms the anchors and chain cables meet the Rules for the vessel’s equipment number. It is a condition of class for vessels with an equipment number of 205 or more, and optional for some smaller vessels, towing craft and steel barges.
• ✠A1 Geographical Limitation (xx NM, xx m Significant Wave Height) — Restricted-service class. The hull is built for operation within a stated distance from land and a stated wave height, for example a coastal service of 100 NM and 5.5 m.
• ✠AMS — Machinery, boilers and systems were built and installed under ABS survey. Intended for all new self-propelled vessels and offshore units.
• AMS — The same machinery notation without the cross: the plant was not built under ABS survey but has been found satisfactory to ABS requirements.
• ✠ACC (Automatic Centralized Control) — Propulsion machinery is controlled and monitored from a continuously manned control station in or next to the machinery space.
• ✠ACCU (Automatic Centralized Control Unmanned) — Control and monitoring from both the bridge and a central station, so the machinery space can be left unattended.
• ✠ABCU (Automatic Bridge Centralized Control Unmanned) — Automation lets the machinery space be periodically unattended, with propulsion controlled mainly from the bridge.
• AIRN, AIRN+ and AIRN-M (a, b) — External airborne noise.
  • AIRN: the vessel meets the airborne noise criteria, confirmed by measurement.
  • AIRN+: the vessel meets the more stringent criteria.
  • AIRN-M (a, b): the noise was measured, with a the averaged A-weighted level at the berth (31.5–8000 Hz) and b the low-frequency level (31.5–160 Hz), both in dB(A).
• All-Electric Vessel — The vessel can run on an all-electric power system built and tested to ABS hybrid and all-electric requirements. All-Electric Vessel [operating mode] adds one or more modes: Power Management (PMT), Power Backup (PBU), Shore Connection (SCN) or Offshore Charging Connection (OCC).
• All-Electric Ready — The design can later be converted to all-electric power with fuel cells, batteries or supercapacitors. Level 1C is a high-level suitability review; level 2D is a detailed one.
• Alternative Fuel Ready family — Alternative Fuel Ready, CNG Fuel Ready, LNG Fuel Ready, Ethane Fuel Ready, LPG Fuel Ready, DME Fuel Ready, Methanol Fuel Ready, Ethanol Fuel Ready, Hydrogen Fuel Ready and Ammonia Fuel Ready show that a vessel is prepared for a named low-flashpoint fuel.
  • Level 1C: the concept design has been reviewed.
  • Level 2D: the detailed design has been reviewed.
  • Level 3: plans are approved and listed parts are installed, shown by letters such as S (hull reinforcement), TA (tank arrangements), BK (bunkering), FS (fuel supply), ME/AE (main/auxiliary engines), GT (gas turbines), MB/AB (boilers) and FC (fuel cells).
• Annual Survey — Hull survey requirements are carried out every year for the first four years of the five-year cycle, with a full Special Periodical Survey, including tank testing, in year five.
• ✠APS — A self-propelled vessel fitted with athwartship thrusters to assist manoeuvring, verified by ABS during construction.
• AT (hull girder component + additional thickness) — Plating is thicker than the Rules require. The notation names the component and the extra thickness to the nearest 0.5 mm, for example AT(DK+0.5).
• AUTONOMOUS (function category, operations supervision level) — A permanently installed autonomous function meets ABS autonomy requirements. The supervision level shows whether an operator watches continuously, periodically or on demand, aboard (OP1–OP3) or remotely (RO1–RO3).
• REMOTE-CON (function category) — A permanently installed remote-control function meets the same requirements. Function categories include navigation, manoeuvring, mooring, docking, propulsion, auxiliaries, environmental protection, cargo handling, ballast and trim, industrial processes and autonomous platform.
• Biofuel-1 and Biofuel-2 — The vessel burns biofuel blends. Biofuel-1 covers blends of up to and including 30% biofuel; Biofuel-2 covers blends above 30%.
• BWE (Ballast Water Exchange) — The ballast water exchange system was designed and surveyed to the ABS Guide, and its operation has been demonstrated. It applies to any vessel type, including FPSOs and FSUs.
• BWT and BWT+ — A ballast water management system with an IMO Member State type approval is installed in line with the ABS Guide. BWT+ adds ABS evaluation to its Rules and manufacture under ABS survey.
• CCO(TDST, TMAT), CCO-POLAR(TDST, TMAT), (HR HOURS) and DE-ICE — Low-temperature operation, where TDST and TMAT are the design service and minimum anticipated temperatures in °C.
  • CCO: basic notation for cold-environment structure and exposed machinery.
  • CCO-POLAR: for continuous operation in polar regions.
  • A trailing +: adds crew equipment and cold-weather training.
  • (HR HOURS): emergency power beyond the 18-hour SOLAS minimum.
  • DE-ICE: for vessels that only occasionally face ice accretion.
• CGSU (Cargo Gear Self Unloading) — Self-unloading cargo gear used in harbour or mild conditions is certified, with an ABS Register of Cargo Gear issued.
• CPS-B, CPS-D, CPS-V, CPS-COT and CorrResistant — Corrosion protection to IMO performance standards.
  • CPS-B: dedicated seawater ballast tanks.
  • CPS-D: double-side skin spaces on bulk carriers.
  • CPS-V: void spaces on bulk carriers and crude oil tankers.
  • CPS-COT: coatings in crude oil cargo tanks.
  • CorrResistant: corrosion-resistant steel as the alternative to coatings in cargo oil tanks.
• CR (Cyber Resilience) — The vessel meets the cyber resilience requirements in Section 4-9-13 of the ABS Marine Vessel Rules.
• Crane and lifting notations: CRC, SC, HC, OC, SP, MRW, RMP, PL, PL+, PL++ and Subsea — CRC means an ABS Register of Lifting Appliances is issued. The letters give the appliance type: SC shipboard crane, OC offshore crane, HC heavy-lift crane, SP special-purpose lifting gear, MRW man-riding winch, RMP ramps and movable decks.
  • PL, PL+ and PL++: personnel lifting with an emergency recovery system, offering controlled luffing and lowering (PL), plus slewing (PL+), or all main crane functions (PL++) after a single failure.
  • Subsea: added to OC or HC cranes for subsea lifting.
• CS-1 and CS-2 — Cybersecurity programmes for a company, owner or manager, applied to a specific vessel. CS-2 adds requirements for policies and procedures, design of the vessel’s cyber risk management system and management of change.
• CS-Ready — For the shipbuilder-integrator: cybersecurity was built into the vessel’s design and construction.
• CS-System — For the equipment maker: the original equipment installed on the vessel meets the cybersecurity requirements.
• DBC (Designed for Bottom Contact) — The hull is designed to rest on the seabed or riverbed for short periods, such as between tides. It applies to barges and ships.
• ✠DPS-0 — Dynamic positioning with centralised manual position control and automatic heading control.
• ✠DPS-1 and ✠DPS-1+ — Automatic position and heading keeping, with manual position control. The “1” marks the redundancy level. The + adds requirements for station-keeping capacity and failure modes of static components.
• ✠DPS-2 and ✠DPS-2+ — Position and heading are kept automatically during and after any single fault, excluding loss of a compartment.
• ✠DPS-3 and ✠DPS-3+ — The same, but also after the loss of a compartment due to fire or flooding.

Common notations, part 2: emissions, fire safety, fuels, monitoring and ice

This group covers environmental performance, enhanced fire protection, alternative fuel systems, crew habitability, hull monitoring and ice strengthening.

• EEDI-Ph3 — The vessel’s verified attained Energy Efficiency Design Index is at or below the required Phase 3 value in MARPOL Annex VI, Regulation 21.
• EFP-A1, EFP-A2, EFP-M1, EFP-M2 and EFP-C — Enhanced Fire Protection, available for vessels, mobile offshore units and offshore installations.
  • EFP-A1 and EFP-A2: accommodation areas, with A1 meeting the less stringent enhanced requirements and A2 the full set.
  • EFP-M1 and EFP-M2: machinery spaces, again less stringent (M1) and full (M2).
  • EFP-C: cargo areas of the vessel types identified in the Guide.
• EGC-OCCS — The vessel carries an onboard carbon capture and storage system built and tested to ABS requirements.
• EGC-OCCS Ready — The design can accept a carbon capture system later. Level 1C is a high-level suitability review; level 2D is a detailed one.
• Exhaust gas cleaning family — EGC-SOx (M), EGC-SOx, EGC-SCR (M), EGC-SCR, EGC-EGR (M) and EGC-EGR.
  • EGC-SOx: scrubbers that cut sulphur oxide emissions.
  • EGC-SCR: selective catalytic reduction that cuts nitrogen oxides.
  • EGC-EGR: exhaust gas recirculation that cuts nitrogen oxides, including systems with extensive off-engine washwater cleaning.
  • The (M) versions cover systems certified to the statutory IMO emissions testing and survey rules; the plain versions are built to the fuller ABS Rules sections.
• EEMS — A permanently installed exhaust emissions monitoring system, with or without an abatement system.
• EHS-P, EHS-C, EHS-F and EHS-E — Enhanced System add-ons to DPS-2 or DPS-3 vessels.
  • EHS-P: power and thruster system beyond the DPS minimum.
  • EHS-C: control computers, position references and sensors.
  • EHS-F: fire and flood protection, needed only for DPS-2 because DPS-3 already goes further.
  • EHS-E: electrical and power management systems.
  • Combinations such as EHS-PCF can be assigned.
• ENVIRO and ENVIRO+ — Compliance with the applicable MARPOL Annexes I, II, IV, V and VI. ENVIRO+ adds ABS criteria for design, management systems, sea discharges and air discharges. These replace the older ES and ES2020 notations.
• ENVIRO-IDP — Oil-to-sea seals and drydock inspections meet the specific requirements of the US Vessel General Permit.
• ERGO TOP, ERGO ES, ERGO VALVE and ERGO MAINT — Ergonomic assessments of the fit between crew and vessel.
  • ERGO TOP: topside structures such as ramps, ladders and platforms.
  • ERGO ES: spaces inside the skin of the vessel, on or below the main deck.
  • ERGO VALVE: access to and ease of use of operating and maintenance valves.
  • ERGO MAINT: safe, easy access to maintenance areas.
• ESA and ESA+ — Enhanced Shaft Alignment. ESA covers the calculation sections of the Guide; ESA+ covers all sections, including installation, sea-trial measurement, maintenance and survey.
• ESP and ESDC — Enhanced Survey Program for oil, bulk, ore, combination and chemical carriers in salt-water service (ESP), and the Expanded Survey Program for general dry cargo vessels (ESDC).
• ESS-LiBATTERY — A lithium-ion battery system of 20 kWh or more used as a power source meets the ABS requirements.
• ESS-SC — A supercapacitor system above 50 Wh used as an additional power source meets the ABS requirements.
• FC-E and FC-NE — A fuel cell power system is used for essential or emergency services (FC-E) or non-essential services (FC-NE). On gas carriers and gas-fuelled ships it is paired with LFFS or GFS.
• FL (years) — The design fatigue life is longer than the 20-year minimum, with the number of years stated. Eligible for SafeHull vessels of the oil, bulk, ore, combination and container types.
• FTS(ν, ρ, T) — Fuel Treatment System approved for fuel up to a stated maximum viscosity at 50°C, maximum density at 15°C and minimum outside air temperature.
• Gas and low-flashpoint fuel family — GFS, LFFS, RELIQ, GCU, DFD, SGF and DFGT.
  • GFS (Gas Fueled Ship): arranged to burn natural gas as fuel, mandatory when fitted.
  • LFFS (Low Flashpoint Fueled Ship): burns a low-flashpoint fuel other than natural gas, such as methanol, ethanol, ammonia or hydrogen.
  • RELIQ: re-liquefaction system for boil-off gas.
  • GCU: gas combustion unit.
  • DFD: dual-fuel diesel engine plant.
  • SGF: single gas fuel engine plant.
  • DFGT: dual-fuel gas turbine plant.
• GRAB [X] — The inner bottom is designed for a specific grab weight in metric tonnes.
• HAB, HAB+ and HAB++ — Crew habitability: accommodation design, vibration, noise, indoor climate and lighting at a minimum level (HAB) and progressively more stringent levels (HAB+ and HAB++).
• HAB(ACCOM), HAB+(ACCOM) and HAB++(ACCOM) — The same three levels, applied to industrial personnel on offshore accommodation vessels.
• HDS — Hull built with higher-ductility steel plates and sections meeting the ABS material Guide, with the extent of use recorded.
• HELIDK and HELIDK(SRF) — A helicopter deck for landing only (HELIDK), or with facilities for storage and refuelling (SRF).
• HIMP — The vessel is enrolled in the ABS Hull Inspection and Maintenance Program.
• HM1, HM1+R and motion monitoring options — A hull condition monitoring system for ship motions. Descriptive names (Slam Warning, Green Seas Warning, Ship Motion, Sea State, Sloshing Monitoring) identify what is monitored. +R adds data recording. Device codes include MOT (motion sensors), ACS (accelerometers), PT (pressure transducers), ST (sea state) and LS (strain gauges).
• HM2, HM2+R and stress monitoring options — A hull stress monitoring system, which can include Hull Girder Stress, Local Load Monitoring, Fatigue Monitor, Structural Temperature Monitoring or an LC loading-computer data link.
• HM3 and voyage-data options — A hull stress monitoring system combined with voyage data recording. Descriptors include VDR, Enhanced VDR, Navigation, Wind, Shaft Monitoring and SL (shore data link), with device codes WD, TM and RC.
• HVSC — A high-voltage shore connection lets the vessel run on shore power alone, so generators can be shut down in port.
• HVSC-Ready — The vessel is designed for a future high-voltage shore connection.
• HYBRID and HYBRID [operating mode] — The vessel uses one or more power sources such as batteries, supercapacitors, fuel cells, wind, solar or conventional generators. Operating modes are Low-Exhaust Emission (LEE), Power Management (PMT), Power Backup (PBU), Power Take-Off/Take-In (PTO/PTI), Shore Connection (SCN), Offshore Charging Connection (OCC) and Electric Mode (EM).
• HYBRID Ready — The design can be converted to hybrid power later, assessed at level 1C or 2D, with mode letters added once drawings are approved.
• Ice Breaker — For vessels whose operating profile includes escort or ice management, with the power and dimensions for aggressive work in ice-covered waters. Assigned to Ice Classes PC1 to PC7.
• Icebreaker* — For PC1–PC7 vessels where hull arrangement, power and scantlings are derived from the icebreaker’s own operational profile and ship-ice interaction scenarios.
• Ice Class IAA, IA, IB, IC, ID and IE — Strengthening for winter navigation in the northern Baltic, in line with the Finnish-Swedish Ice Class Rules. IAA to IC cover heavier ice, while ID and IE cover very light and extremely light ice.
• Ice Class PC1 to PC7 — Strengthening for independent navigation in ice-covered polar waters, with PC1 the highest and PC7 the lowest of the Polar Classes.

Common notations, part 3: health, ice loads, bridges, maintenance and power service

This group moves from infection control and hazardous materials to navigation bridges, emissions limits, maintenance programmes and power generation services.

• IDM-A (Infectious Disease Mitigation – Arrangements) — Marine and offshore assets meet the minimum arrangement criteria in the ABS guide on limiting infectious disease transmission on board.
• IHM (Inventory of Hazardous Materials) — The vessel’s hazardous materials inventory has been reviewed and verified by ABS. Available for new and existing vessels.
• ILM, (n), +T, +G, +L and +P — Ice loads monitoring.
  • ILM: basic system that monitors hull girder bending stress.
  • (n): number of extra strain gauge locations beyond the basic system.
  • +T: ice loads on the quarters caused by turning in ice.
  • +G: global loads, with hull girder bending and shear monitored, typically for ramming.
  • +L: recording of local stresses for ice-load analysis.
  • +P: measuring and recording of local ice impact pressures.
• ISQM and SQM — Control-system software developed under the ABS Integrated Software Quality Management Guide, from concept through verification and validation. ISQM is for integrated control systems; SQM is for non-integrated ones.
• LAID UP — The vessel is in lay-up under the ABS lay-up and reactivation requirements. Surveys falling due are held in abeyance until it is reactivated.
• LEV(EU) and LEV(US) — Low Emissions Vessel. Specified engines meet limits stricter than MARPOL Annex VI. LEV(EU) means all identified engines meet EU Stage V; LEV(US) means all identified engines over 600 kW meet US EPA Tier 4.
• Line Cutter — Line cutters are fitted to reduce the risk of propeller entanglement and shaft seal damage from ropes or lines.
• LSC and LSC(DC) — Loading and Stability Computer software that checks hull girder loading and stability. LSC(DC) also assesses actual damage conditions using inputs from detection systems on board.
• LVDC-DIST — An optional notation for vessels with a DC power distribution system, where sources, major loads or storage connect to a DC bus directly or via converters.
• LVSC and LVSC-Ready — A low-voltage shore connection lets the vessel run on shore power alone with generators shut down in port. The Ready version means the vessel is designed for a future installation.
• MAN and MAN-A — Manoeuvrability. MAN means the vessel meets IMO manoeuvrability standards with an overall rating of 1 or more. MAN-A requires all non-rated criteria to be met, each rated criterion at 1 or more and an overall rating of 2.5 or more.
• MLC-ACCOM, MLC-ACCOM(SPS) and MLC-ACCOM(WB) — Seafarer accommodation and its ambient conditions (vibration, noise, indoor climate, lighting) meet the ILO Maritime Labour Convention guidance. The SPS version applies the allowances for special purpose ships; the WB version is for non-SPS vessels such as offshore support vessels and tow boats.
• MOVDK (Movable Deck) — Movable vehicle decks or platforms are designed and built to ABS requirements. Applies to dry cargo vessels, vehicle carriers, steel barges, high-speed craft and naval vessels.
• NBL (Navigational Bridge Layout) — The bridge is laid out on sound ergonomic principles and equipped under ABS survey.
• NBLES and NBLES+ — Bridge layout plus listed navigational equipment and systems. The “+” adds equipment on the bridge wings.
• NBLES (COS) — The same approach tailored to vessels working in coastal and narrow waters.
• NIBS (Navigational Integrated Bridge System) — An integrated bridge system for navigation that meets IMO bridge-integration guidelines and the ABS bridge design guide.
• NOx-Tier III — Every marine diesel engine above 130 kW, unless exempt, is certified to the MARPOL Tier III NOx limit with an approved NOx Technical File and EIAPP certification.
• (OSR-C1) and (OSR-C2) — Vessels or barges built for oil recovery but not outfitted for it. OSR-C1 covers oil of unknown flash point; OSR-C2 covers oil with a flash point above 60°C.
• ✠PAS — A non-self-propelled vessel fitted with thrusters to assist manoeuvring or propulsion while under tow.
• PMP and PMP+ — Preventative Maintenance Program for planned maintenance, condition monitoring or both. The plain notation means less than 50% of the equipment under Continuous Survey-Machinery is enrolled; “+” means more than 50%.
• PMP-CBM and PMP-CBM+ — Condition-based maintenance using real-time monitoring.
• PMP-RBMD and PMP-RBMD+ — Reliability-based maintenance together with design for reliability.
• PMP-RCMD and PMP-RCMD+ — Reliability-centred maintenance together with design for reliability.
• PMP-RBM and PMP-RBM+ — Reliability-based maintenance on its own.
• PMP-RCM and PMP-RCM+ — Reliability-centred maintenance on its own.
• PMP, SMART (MHM), PMP-CBM, SMART (MHM), PMP+, SMART (MHM) and PMP-CBM+, SMART (MHM) — Machinery in a preventative maintenance programme is also enrolled in the alternate means to credit survey requirements under the ABS Smart Functions guide.
• PMP-MS — Maintenance System: all of the vessel’s survey-eligible machinery is enrolled and the operator uses a computerised maintenance management system.
• POLAR(Category, PST) and POLAR Ready(Category, PST) — Compliance with the IMO Polar Code, stating the ship category and Polar Service Temperature. The Ready version means the required equipment is on board but the operational assessment and Polar Water Operations Manual are not yet done.
• PORT — Automatic and remote control and monitoring systems for operation in port are installed and tested under survey.
• POT — Protection of Fuel and Lubricating Oil Tanks, for vessels with an aggregate fuel oil capacity of 600 m³ and above.
• Power Service and ✠Power Plant — Power Service is for barges, ships and offshore units that generate power for others. Power Plant covers the generation and distribution equipment built, installed and commissioned to the full requirements.
• Power Service (Nuclear) — For barges, ships and offshore units with an onboard nuclear power system used for generation rather than propulsion.

Common notations, part 4: redundancy, structure, management systems and propulsion

The last common group covers propulsion redundancy, remote surveys, hull strength and fatigue, management systems, tailshaft monitoring, noise, vibration and wind propulsion.

• R1 and R1+ — Redundancy for a vessel with multiple propulsion machines but only one propulsor and steering system. With “+”, propulsion can be maintained or quickly restored after a single failure well enough to hold position in adverse weather without drifting. Without it, the vessel keeps course and manoeuvrability but is not intended to withstand that weather.
• R1-S and R1-S+ — A single propulsor, with the propulsion machinery split between separate spaces so that fire or flooding in one does not disable the other.
• R2 and R2+ — Multiple propulsion machines, multiple propulsors and steering systems.
• R2-S and R2-S+ — Multiple machines, propulsors and steering systems, arranged in separate spaces so one fire or flood cannot disable all propulsion.
• REMSUR1 and REMSUR2 — Remote surveys and audits. REMSUR1 means the vessel has the capability and ICT for remote surveys but is not eligible for consecutive remote surveys. REMSUR2 means it is eligible for consecutive remote surveys, subject to flag Administration agreement for statutory ones.
• RES (Residual Strength) — For oil or fuel oil carriers, bulk or ore carriers, combination carriers and container carriers built using the ABS procedure for evaluating hull-girder residual strength.
• Restricted Service (xx NM, xx m or ft Significant Wave Height) — The vessel is built for a specific route between stated geographical limits, with a distance and wave-height restriction recorded in the notation.
• RRDA — Rapid Response Damage Assessment: the vessel is classed under the ABS guide for fast damage assessment.
• RW — Reduced Weight anchors of proven superior holding ability, for vessels with the Circle E symbol. Their mass may be up to 25% below the standard table value.
• S, SQ, SE, SEn, HS, SQE, SQEn, SEEn, HSQ, HSE, HSEn, SQEEn, HSEEn, HSQEn, HSQE and HSQEEn — Management system notations under the ABS Marine Management Systems guide. Each letter adds a scope: S safety, H health, Q quality, E environmental and En energy. For example, HSQE covers safety, health, quality and environmental requirements.
• SEC — Ship Security. The vessel and mobile offshore drilling units meet requirements derived from SOLAS Chapter XI-2, the ISPS Code and US Coast Guard security regulations.
• SElev (Shipboard Elevator) — An installed shipboard elevator is certified by ABS under its lifting appliance guide.
• SFA(years) — Spectral Fatigue Analysis was carried out and the vessel built to the approved plans. The number shows a design fatigue life of at least 20 years, in 5-year steps.
• SFA(years, WWT) — The same analysis for worldwide trading, with the 20-year minimum applying to the worldwide environment.
• SH (SafeHull) and SHCM — SafeHull is the ABS design approach for bulk and ore carriers, combination carriers, container carriers over 130 m and membrane-tank LNG carriers. SHCM means the SafeHull Construction Monitoring Program was followed during build.
• SHR — The vessel was built to plans approved by another recognised society, and ABS has reviewed the scantlings within 0.4L amidships against its own requirements.
• SH-DLA (SafeHull-Dynamic Loading Approach) — The hull was evaluated with an enhanced structural analysis of behaviour under dynamic loads.
• SKP and SKP(a,b,c,d,e,f) — Station-keeping performance information for stated limiting wind, wave and current. The six-letter form gives probabilities of staying on station at a stated site, with all thrusters running and after loss of the least- or most-critical thruster.
• SLAM-B and SLAM-S — Strengthened against slamming. SLAM-B covers bottom and bow-flare slamming; SLAM-S covers stern slamming.
• SMART (INF), SMART (MHM) and SMART (SHM) — Smart Function systems under the ABS guide: INF for the data infrastructure, MHM for machinery health monitoring and SHM for structural health monitoring. They can be combined.
• SOx Scrubber Ready — Level 3 of the ABS scheme: drawings approved and listed equipment installed. Descriptive letters cover hull structure (HS), scrubber configuration and integration (SC), exhaust gas system (EG), washwater (W), chemical treatment (C) and residue handling (R).
• SPMA — Mooring arrangements meet Section 3-5-2 of the ABS Marine Vessel Rules.
• SSV — Software Systems Verification: the control-system software in an ABS-reviewed verification plan meets the CyberSafety Volume 4 guide. It does not cover the connected equipment.
• STBLess-W (SternTubeLess – Water Lubricated) — An open-loop, water-lubricated bearing with a stern inspection chamber, so bearings can be inspected and replaced without pulling the tailshaft. ESA and TCM-W are prerequisites.
• SUSTAIN-1 and SUSTAIN-2 — Sustainability notations. SUSTAIN-1 meets Section 2 of the ABS sustainability guide; SUSTAIN-2 meets both Sections 2 and 3.
• TCM — Tailshaft Condition Monitoring for oil-lubricated stern tube bearings.
• TCM-PS — Tailshaft Condition Monitoring with a Protective Seal that can fully eliminate oil discharge at the oil-to-sea interface, removing the need for environmentally acceptable lubricants.
• TCM-W — Tailshaft Condition Monitoring for water-lubricated stern tube bearings, closed or open type.
• UWILD (UnderWater Inspection in Lieu of Drydocking) — The owner may request an underwater inspection as an alternative to drydocking. Not applicable to vessels aged 15 or over that are under the Enhanced Survey Program.
• UWN (Q), UWN+ (Q), UWN (T) and UWN+ (T) — Underwater radiated noise. Q is the quiet condition for low-speed operation in sensitive areas; T is the transit condition for normal operation. The “+” versions have more stringent criteria.
• UWN (R) — The underwater noise notation for research vessels.
• UWN (AT) and UWN (AL) — Acoustic research vessels, in the thruster condition (AT) and the light survey condition (AL).
• VIB-M — Machinery vibration meets the ABS acceptance criteria, verified by measuring local structures that support machinery and nearby affected spaces.
• Wind-Assisted, Wind-Assisted+ and Wind-Assisted Ready — A wind-assisted propulsion system is installed and meets the minimum class requirements. The “+” version meets and is certified to the additional requirements. Ready means a system is planned for the future and the design complies.

• Wind-SC — For an offshore support vessel (or a steel or aluminium vessel) that meets the ABS Requirements for Building and Classing Wind Farm Support Vessels.

Vessel types, part 1: structural rules, bulk, chemical, container and dry cargo ships

From here the notations belong to a specific vessel type. They sit on top of the common symbols above, so a bulk carrier’s class line might combine ✠A1, Bulk Carrier, BC-A and several optional extras.

Common structural rules, support and aquaculture vessels

• CSR, AB-CM — Bulk carriers and oil tankers designed and built to the IACS Common Structural Rules (Parts 5A and 5B of the ABS Marine Vessel Rules) and to the ABS Construction Monitoring Program.
• Anchor Handling Vessel — A vessel, other than an offshore support vessel, designed mainly for anchor handling and built to Part 5C, Chapter 22 of the Marine Vessel Rules.
• ASV-Support — Fish farm support vessels that inspect, maintain and repair aquaculture installations, delouse fish, carry fish pellets or harvest fish.
• ASV-Fish Pellet — Fish pellet carriers, with holds that move pellets from shore to fish farms.
• ASV-Live Fish — Live fish carriers, with systems and tanks to load, unload, store and carry live fish.
• Fish Farm Installation, Manned (hull type) and Fish Farm Installation, Unmanned (hull type) — Non-self-propelled, sited aquaculture installations. The hull type is Spar-Type, Column-Stabilized, Ship-Shape or Non-Buoyant.
• Asphalt Carrier with Independent Tanks (temp°C) — Carries asphalt in independent tanks at a stated maximum design cargo temperature.

Bulk carriers

• Bulk Carrier — A single-deck ship with topside and hopper side tanks, intended mainly to carry dry cargo in bulk. Includes ore carriers and combination carriers.
• Bulk Carrier, BC-A, BC-B and BC-C — Loading-condition notations.
  • BC-A: dry bulk cargoes of 1.0 t/m³ or denser, with specified holds allowed empty, in addition to BC-B conditions.
  • BC-B: cargoes of 1.0 t/m³ or denser with all holds loaded, in addition to BC-C conditions.
  • BC-C: cargoes lighter than 1.0 t/m³.
  • A maximum cargo density (xx t/m³) is added where the ship is not designed for cargoes of 3.0 t/m³ or more.
  • (no MP) is added where the ship is not designed for loading and unloading in multiple ports.
• Box-Shaped Bulk Carrier — Double side skin without upper and lower wing tanks, or with small topside tanks, along the full length and height of the holds. Built to Part 5C, Chapter 19.
• Ore Carrier — Two longitudinal bulkheads and a double bottom throughout the cargo area, carrying ore in the centre holds only.
• Ore or Oil Carrier — The same arrangement, but able to carry ore in the centre holds or oil in the centre holds and wing tanks.
• Great Lakes Service — A geographical limitation notation for bulk carriers built for the Great Lakes and the St. Lawrence Seaway, with machinery aft and a double bottom with side tanks.
• DWA (Deep Water Anchoring) — For bulk carriers of 150 m or more whose anchor, chain, windlass and supporting structure meet the ABS deep-water anchoring guide. Written as ✠A1 Ⓔ DWA.
• LDCARE1, LDCARE2 and TML — Special loading of ore.
  • LDCARE1: ore-carrying vessels meeting the basic special-loading requirements, with a stated loading rate and overshoot time.
  • LDCARE2: adds automatic draft-reading sensors and automatic ballast tank level gauging linked to the loading program.
  • TML: vessels carrying iron ore fines (transportable moisture limit).
• PMA and PMA+ — Means of access for inspection of bulk carriers of 20,000 GT and over built on or after 1 January 2006, meeting the SOLAS and IMO technical provisions. PMA+ adds ergonomic features such as opening sizes, headroom, guardrail heights and ladder angles.

Chemical and compressed gas carriers

• Chemical Carrier (Ship Type X) — Designed or adapted to carry the liquid chemicals listed in Section 17 of Part 5C, Chapter 9 of the ABS Marine Vessel Rules. Type 1 is for the most severe environmental and safety hazards, Type 2 for appreciably severe ones, and Type 3 for sufficiently severe ones.
• BLU — Bow loading and unloading arrangements meeting ABS requirements. Also used on oil and gas carriers.
• SLU — Stern loading and unloading arrangements. Also used on oil and gas carriers.
• ECTC(C) and ECTC(SC) — Enhanced Cargo Tank Cleaning. ECTC(C) covers cargo tanks and their cleaning systems; ECTC(SC) extends it to slop tanks.
• Compressed Natural Gas Carrier — Designed for carrying compressed natural gas in bulk under the ABS compressed gas guide.

Container carriers

• Container Carrier — Built mainly to carry containers in holds, on deck or both, with cell guides and pedestals. Built to Part 5C, Chapter 5 (130–450 m) or Chapter 6 (under 130 m).
• CSC (Container Securing Certificate) — The initial container securing system installation has been certified by ABS for unrestricted service.
• CLP, CLP-V and CLP-V(PARR) — Certified onboard computer lashing programs, all requiring CSC.
  • CLP: the program is certified.
  • CLP-V: also certified for specific voyage routes, and mandatory where voyage-specific reductions are applied.
  • CLP-V(PARR): adds route splitting and parametric roll detection.
• EBCAD (Enhanced Brittle Crack Arrest Design) — Two or more extra crack prevention or arrest measures along the cargo hold region, plus non-destructive testing, for thick high-strength steel plates.
• ERGO(LASH) and ERGO(LASH)-R — Ergonomic container lashing. The first suits new and existing ships; the “-R” version applies good practice to existing ships.
• FOC, FOC-R, FOC+, FOC-R+, CCH, FBC and CHF — Container ship fire-fighting.
  • FOC: on-deck fire-fighting beyond SOLAS.
  • FOC-R: a restricted version where full compliance is not practical.
  • FOC+ and FOC-R+: add hatch cover protection and fire-fighters’ breathing apparatus.
  • CCH: cooling and air monitoring to protect crew spaces from heat and smoke.
  • FBC: enhanced detection, extinguishing and cooling inside container holds.
  • CHF (Container Hold Flooding): arrangements and procedures to flood a hold to help put out a fire.
• PARR-C1 and PARR-C2 — Parametric roll under control, based on a roll damping model, simulations and operating guidance. PARR-C2 adds anti-rolling devices proven against parametric roll.
• SPR — Springing assessment satisfied, including fatigue strength criteria for thick high-strength plates.
• WIP — Whipping assessment satisfied, covering hull girder ultimate strength and fatigue strength.

Crane and dry cargo vessels

• Crane Vessel — Main function is crane operations with heavy lift cranes of 160 metric tonnes or more, built to Part 5C, Chapter 21. The cranes are certified and the CRC notation is maintained throughout the vessel’s life.
• General Dry Cargo Vessel — Carries diverse dry cargoes in compatible combinations and packaging, such as boxes, bales, barrels and drums. May include deck cargo ships with no holds.

Vessel types, part 2: gas, oil, passenger, refrigerated and other ships

Liquefied gas carriers

• Liquefied Gas Carrier — Designed for carrying liquefied gases and other products listed in the ABS Rules and the IMO gas carrier codes. Multi-cargo gas carriers are classed under this notation.
• Liquefied Hydrogen Carrier — Designed and built to carry liquefied hydrogen under the ABS liquefied hydrogen carrier requirements.
• Liquefied Natural Gas Carrier — Carries LNG with a methane content above 80%, built to Part 5C, Chapter 8 or 12.
• Liquefied Gas Carrier with Independent Tanks — Gas carriers built to the ABS guide for independent-tank designs.
• Liquefied Carbon Dioxide Carrier — Built for liquefied carbon dioxide under the ABS CO₂ carrier requirements. Gas carriers approved for multiple cargoes are not eligible and use the general gas carrier notation instead.
• Liquefied Gas Carrier, Storage Service; Liquefied Natural Gas Carrier, Storage Service; and Liquefied Gas Carrier with Independent Tanks, Storage Service — Gas carriers that also meet the additional ABS requirements for storage service.
• BLU and SLU — Bow and stern loading and unloading arrangements, as for oil and chemical carriers.
• DFD — Dual-fuel diesel engine power plant, mandatory when fitted. A note names any fuel other than natural gas.
• DFGT — Dual-fuel gas turbine power plant, mandatory when fitted.
• GCU — Optional gas combustion unit to dispose of boil-off gas, built and installed under survey.
• RELIQ — Optional re-liquefaction system. It may also be granted to gas carriers other than LNG carriers, such as LPG carriers.
• LNG Bunkering and LNG Bunkering, VRS — A gas carrier arranged for regular LNG bunkering service. VRS adds a vapour return system. RELIQ, GCU or DFD can be added when that equipment is fitted.
• LNG Cargo Ready — The design is suitable for LNG carriage at a future date. Descriptive letters show what is installed: cargo containment (CC), cargo piping (CP), cargo pump (PP), gas compressor (CO), re-liquefaction (RS), gas combustion unit (GC), fuel gas supply (FG) and dual-fuel engine (DF). It is combined with a Liquefied Gas Carrier notation.
• (LNG) R — An LNG carrier on which the owner has installed a regasification facility, so it can load, transport and regasify LNG for direct discharge ashore.

Oil carriers

• Fuel Oil Carrier — Carries petroleum products other than crude with flash points above 60°C (closed cup).
• Oil Carrier — Carries petroleum products, including crude oil, with flash points at or below 60°C, and similar types such as combination carriers.
• Oil Carrier, Storage Service — An oil carrier operating in oil storage service under the ABS offshore unit rules.
• Oil Storage Service — A vessel that has reached its MARPOL phase-out date and is used for oil storage.
• BLU and SLU — Bow and stern loading and unloading arrangements.
• CPP (Cargo Piping Protected) — At the owner’s request, all cargo piping and valve control piping is located above the double bottom. It is not a condition of class.
• DWA — Deep Water Anchoring for oil carriers of 150 m or more, with anchor, chain, windlass and support structure meeting the ABS guide.
• ECTC(C) and ECTC(SC) — Enhanced Cargo Tank Cleaning for cargo tanks and, with (SC), slop tanks.
• IGS – Ballast — An inert gas installation that also supplies inert gas to ballast tanks.
• PMA and PMA+ — Means of access for inspection on oil carriers of 500 GT and over built on or after 1 January 2006. PMA+ adds ergonomic provisions.
• SPMA — Mooring arrangements meeting Section 3-5-2 of the Marine Vessel Rules.
• VEC and VEC-L — A vapour emission control system, and (VEC-L) one that is also suitable for lightering operations.

Passenger and refrigerated cargo vessels

• Passenger Vessel — Designed and fitted to carry more than 12 passengers, built to Part 5C, Chapter 7.
• COMF and COMF+ — Passenger comfort. COMF meets minimum criteria for vibration, noise, indoor climate and lighting; COMF+ adds stricter vibration criteria, including motion sickness.
• SRtP (Safe Return to Port) — For passenger ships of 120 m or more, or with three or more main vertical zones, meeting the SOLAS safe return to port provisions.
• ✠IRCC (Integral Refrigerated Container Carrier) — Arranged to carry plug-in refrigerated containers that need ship’s power, cooling water and temperature monitoring.
• ✠IRCC-SP xxx/xx — The same, with two figures: the number of certified refrigerated container positions and the percentage that may carry fruit or chilled cargo.
• ✠RC(Hold No.) — Only the listed holds are equipped for refrigerated cargo.
• ✠RCC (Refrigerated Cargo Carrier) — Arranged for refrigerated cargo in insulated holds.
• ✠RCCC (Refrigerated Cargo Container Carrier) — Carries porthole-type refrigerated containers cooled by the ship’s refrigeration machinery.
• ✠REBLT (Refrigerated Edible Bulk Liquid Tanker) — Carries edible liquids in refrigerated cargo tanks.
• ✠RFC (Refrigerated Fish Carrier) — A fish processing or storage vessel with refrigerated holds for chilling, cooling or freezing fish.
• RMC (Refrigeration Machinery Certified) — An existing vessel whose refrigeration machinery was not built under ABS survey but meets the older ABS requirements.
• ✠CA (Controlled Atmosphere) — Equipment supplies nitrogen or an equivalent gas to the holds, with safety features.
• ✠CA (INST) — A permanent piping system ready for connection to portable controlled atmosphere generating equipment.
• (F) Fruit Carrier — A refrigerated cargo or container ship suitably designed for carrying fruit in holds or containers.

Other cargo-carrying vessels

• Semi-Submersible Heavy Lift Vessel — Loads and unloads deck cargo by temporarily submerging its cargo deck through ballasting.
• SWATH Vessel — Small Waterplane Area Twin Hull craft operating at speeds where dynamic lift is not a design feature, approved for unrestricted ocean service.
• Vehicle Carrier — Carries roll-on/roll-off cargo, including vehicles, pallets and containers on wheeled units, such as pure car carriers and ro-ro ships.
• Vehicle Passenger Ferry — Carries vehicles and more than 12 passengers, also known as a ro-ro passenger ferry.
• EFP-C(EV) — A vehicle carrier with ro-ro cargo spaces designed for electric vehicles.
• Water Carrier — Specifically fitted to carry water in bulk in cargo tanks, built to Part 5C, Chapter 11.

Steel vessels under 90 m: tugs, fishing and fire-fighting craft

These notations cover smaller steel workboats under 90 m (295 ft) in length.

• (Operational Area) Domestic Service — Built to Appendix 5C-A1-3 for restricted domestic service, with the restricted area named in the class designation.
• Ⓔ-(R) — Equipment notation for vessels under 90 m not built under ABS survey, where the existing anchors, chains and windlass are certified by another recognised society.
• Escort Vessel and Escort Vessel (dual purpose) — Vessels that assist disabled ships that have lost propulsion or steering. The dual-purpose version also carries out additional services and must meet the rules for those as well.
• FFV1, FFV2 and FFV3 — Fire Fighting Vessel capability.
  • FFV1: can fight external fires and has a water spray system to cool its own surfaces for close operation in the early stages.
  • FFV2 and FFV3: arranged to fight large fires continuously and cool burning structures, with capabilities set out in Table 1 of the ABS offshore support vessel rules.
• FFV1 and 2 and FFV1 and 3 — Vessels with FFV2 or FFV3 that also meet the FFV1 requirements.
• (FF Capable) — A designation for vessels not fully built to the Rules but with some fire-fighting capability beyond their regular service, reviewed under the intent of the Rules.
• Fishing Vessel, Side Trawl, Stern Trawl and Torremolinos Convention — Fishing Vessel is for ships that catch or harvest living marine resources, including those that process their catch. The record notes Side Trawl or Stern Trawl. Torremolinos Convention shows compliance with the 1977/1993 Protocol on safety of fishing vessels.
• OSR-S1 and OSR-S2 — Oil spill recovery vessels outfitted for the work. S1 covers oil of unknown flash point; S2 covers oil with a flash point above 60°C.
• (OSR-C1) and (OSR-C2) — Built for oil recovery but not outfitted for it, for unknown flash point oil (C1) and oil above 60°C flash point (C2).
• Towing Vessel, BP (xx) and QR — A vessel designed mainly for towing. BP (xx) gives the static bollard pull in metric tonnes from an approved test, with the power duration stated if it is time-limited (hybrid or battery mode). QR means a remotely controlled quick release for the towing hook or winch.
• Towing Vessel ATB — Articulated tug-barge: the tug is secured in the barge notch by mechanical means rather than just lines, and can push the barge or tow it by hawser. Tug and barge are classed as two vessels, cross-referenced.
• (geographical limitations) Towing Vessel ITB — Integrated tug-barge, with the tug mated to the barge through a special mechanical connection, classed as two separate vessels.
• ✠ABCU-H — Harbour version of ABCU for a towing vessel under 500 GT and between 20 m and 46 m long, with an unmanned engine room limited to restricted harbour operations.
• HAB(WB), HAB+(WB) and HAB++(WB) — Crew habitability for workboats: offshore support vessels, tugs, tow boats, dredgers, research vessels and anchor handlers. The levels rise in stringency from HAB(WB) to HAB++(WB).
• RB — Rebuilt: the vessel under 90 m has been surveyed, analysed and repaired so it can keep working past its normal 20–25 year life.

Offshore Support Vessels

Offshore Support Vessel (OSV) notations describe a ship’s specialised function. A vessel built for several functions can carry a combination, as long as it meets the requirements for each.

• Offshore Support Vessel — The base notation, for vessels primarily designed for offshore support and built to Parts 3 and 4 plus at least one specialised functional service in Part 5D.
• Offshore Support Vessel (Dual and Multi-Function Service) — Vessels intended for several functional services can be assigned a combination of notations, provided each service’s requirements are met and the vessel is ready to carry them out at all times.
• SPS — The vessel meets the ABS requirements and the IMO Code of Safety for Special Purpose Ships.
• (Operational Area) Domestic Service — Built to Section 5D-1-3 for domestic service at offshore sites, with the area named in the class designation.
• Ⓔ-(R) — Equipment notation for OSVs not built under ABS survey, where existing anchors, chains and windlass are certified by another recognised society.
• HDC(P, Locations) and HLC(ρ, Tanks) — Strengthening for heavy cargo. HDC covers heavy deck cargo above 25.66 kN/m² (shown as the deck load P and its locations); HLC covers heavy liquid cargo with a specific gravity above 1.05 (shown as the cargo density ρ and the tanks).
• Offshore Support Vessel (Supply), (Supply-CHEM) and (Supply-HNLS) — Vessels for supplying offshore installations. Supply-CHEM also carries hazardous and noxious liquids or chemicals in bulk under the OSV Chemical Code; Supply-HNLS does so under flag Administration guidelines.
• Offshore Support Vessel (AH) and (TOW) — Designed and equipped for anchor handling (AH) or towing (TOW).
• Offshore Support Vessel (FFV 1), (FFV 1 NS), (FFV 2), (FFV 3), (FFV 1 and 2), (FFV 1 and 3) and FF Capable — Fire-fighting.
  • FFV 1: water spray protection to allow close approach in early fire-fighting and rescue.
  • FFV 1 NS: the same fire-fighting capability without water spray protection, so not equipped for close operation.
  • FFV 2 and FFV 3: continuous fighting of large fires and cooling of burning structures.
  • FFV 1 and 2, FFV 1 and 3: FFV 2 or 3 vessels that also meet FFV 1.
  • FF Capable: some fire-fighting capability in addition to regular service.
• Offshore Support Vessel (DSV AIR), (DSV MIXED-GAS), (DSV SAT) and (ROV) — Support for air diving, mixed-gas diving, saturation diving or remotely operated vehicles. A vessel supporting several systems is written as, for example, (DSV AIR/SAT).
• DSV Capable and ROV Capable — Vessels with some diving or ROV support capability in addition to their regular service.
• Offshore Support Vessel (OSR-S1), (OSR-S2), (OSR-C1) and (OSR-C2) — Oil spill response vessels that recover oil from the water and shorelines. The S versions are outfitted for recovery (S1 for oil of unknown flash point, S2 for flash point above 60°C); the C versions are built for it but not outfitted.
• Offshore Support Vessel (SSR) — Adapted for evacuation, reception, rescue and care of people from another vessel or installation at sea, and approved for safety standby service.
• GR A – (N), GR B – (N) and GR C – (N) — Safety standby groups by survivor capacity N: Group A more than 300, Group B from 20 to 300, Group C fewer than 20.
• SSR Capable (number of survivors, operational area) — Some safety standby rescue capability in addition to regular service.
• Offshore Support Vessel (Pipe Lay) — Designed and equipped for installing subsea pipelines.
• Offshore Support Vessel (Heavy Lift) — Lifts heavy loads of 160 metric tonnes or more in drilling, production, construction or salvage work.
• Offshore Support Vessel (WI), (WI-READY), (WIR) and (WIR-READY) — Well intervention. WI means a riserless well intervention system is fitted; WIR means a riser-based system is fitted. The READY versions mean the design is prepared for such a system.
• Offshore Support Vessel (WS) and (WS-READY) — Fitted with a well stimulation system, or designed to be well stimulation ready.
• Offshore Support Vessel (Well Test) and (WT-READY) — Fitted with a well test system, or designed to be well test ready.
• Offshore Support Vessel (Escort) — Intended for escort service, accompanying another vessel in transit.
• Offshore Support Vessel (Wind IMR) — Intended for installation, maintenance and repair of wind turbines.
• Offshore Support Vessel (Cable Lay) — Designed and equipped to install, maintain and repair telecommunication and power cables.
• Offshore Support Vessel (Subsea Service) — Installation support, inspection, maintenance, repair or decommissioning of subsea trees, wellheads, manifolds and similar equipment.
• BP (xx) — Bollard pull in metric tonnes from a test, for OSVs in towing or escort service. Mandatory for those services.
• GRC(Type I or II, PS, or AS) — A permanently installed offshore access gangway with an ABS register. Type I allows unrestricted personnel flow and is supported at both ends; Type II allows limited flow. PS means passive motion compensation and AS means active motion compensation.
• IP (Industrial Personnel) — The OSV complies with the IMO Industrial Personnel Code (Resolution MSC.527(106)).
• QR and QR+ — Quick release for the towing rope or wire on OSVs handling anchors of floating installations or towing. QR+ adds an approved emergency release for the towing winch for work in close quarters, ports or terminals.

Naval ships, high-speed craft, light warships and yachts

These four groups sit outside the ordinary merchant fleet. Each has its own ABS rule set, and several carry notations that are listed as private in the ABS Record.

Naval ships

Built to the ABS Guide for Building and Classing International Naval Ships.

• NAVAL COMBATANT — Ships for higher-threat environments whose main mission uses own-ship weapons within a theatre of operations. Typical examples are cruisers, destroyers, frigates and corvettes.
• NAVAL FORCE PROJECTION — Higher-threat ships whose main mission is carrying military personnel or other craft, such as aircraft and landing craft, to and within a theatre. Examples are conventionally powered aircraft carriers, helicopter carriers and amphibious assault ships.
• NAVAL SUPPORT — Ships for lower-threat environments such as escort duties or EEZ protection. They include fleet replenishment ships, landing ships, supply ships and mine warfare vessels.
• COAST GUARD — Coast guard vessels whose main mission is maritime safety, mobility, law enforcement, environmental protection and national security. Cutters, patrol boats, buoy tenders and icebreakers are appended as a further descriptor.
• NAVAL CRAFT, COASTAL NAVAL CRAFT and RIVERINE NAVAL CRAFT — Higher-speed, shorter-range naval vessels such as patrol and fast attack craft. Coastal craft may go no more than 300 miles from a safe harbour (150 miles in Winter Seasonal Zones) and may not cross oceans. Riverine craft work in rivers, harbours and coastlines within 50 miles of a safe harbour.
• GOVERNMENT SPECIAL PURPOSE — Government vessels not covered by other naval notations, such as border patrol boats and harbour authority patrol boats.
• US NAVAL AUXILIARY SERVICE — Naval vessels built to military specifications rather than class rules, now transferring into ABS class.
• AB (Weight, Range) — The structure above the waterline survives an air blast of a stated equivalent TNT weight at a stated range, with only superficial damage. A private notation.
• BFP1, BFP2 and BFP3 — Ballistic and fragment protection, also private. BFP1 is a basic level that conceals assets from direct line of sight. BFP2 is a medium level that slows projectiles and fragments. BFP3 is an enhanced level where the structure, doors, windows and openings cannot be penetrated by the designated threat.
• CBP (S1, S2 or S3); (M1, M2 or M3, by system) — Enrolment in the Condition-Based Program for Government Vessels, with tiers for hull items (S) and machinery systems (M).
• CBP Ready (S1, S2 or S3); (M1, M2 or M3, by system) — The vessel meets the Ready-level requirements of the same programme.
• COMF(G) — Government vessel comfort criteria for vibration, noise, indoor climate and lighting, with alternative government standards allowed by agreement.
• HAB(G) — The government-vessel version of crew habitability, with the same allowance for alternative standards.
• HHP and SHHP — High Holding Power anchors with proven holding power of at least twice that of an ordinary stockless anchor, and Super High Holding Power anchors at least four times.
• NavalSafe(x) — For conventionally powered, non-nuclear government surface craft meeting the Naval Ship Code once the Naval Ship Safety Certificate is issued. The index x names the chapter: S structure, BSC buoyancy/stability/controllability, ES engineering systems, SS seamanship systems, FS fire safety, EER escape/evacuation/rescue, C communication, N navigation, DG dangerous goods, or All.
• UHS — The hull structure within 0.4L amidships complies with the Guide’s requirements for sea-going conditions.
• UNDEX (Weight, Range) — The structure below the waterline resists underwater shock with only superficial damage. Several scenarios can be listed, for example UNDEX (W1, R1, W2, R2).
• UNREP (Beam, Stern, Fore, Vert) — Underway replenishment. Beam is side-to-side transfer, Stern and Fore are transfers through the receiving ship’s stern or fore arrangements, and Vert is replenishment by air lifting. A ship may hold any combination.

High-speed craft

Built to the ABS Rules for Building and Classing High-Speed Craft.

• HSC — Craft built to the HSC Rules, distinguished as ✠A1 HSC ✠AMS. Covers monohulls under 130 m, multihulls under 100 m, surface effect ships under 90 m and hydrofoils under 60 m.
• HSC Coastal Craft and HSC Riverine Craft — Coastal craft stay within 300 miles of a safe harbour; riverine craft within 50 miles. Neither may make transoceanic voyages.
• HSC Passenger Craft (A), (B) and HSC Ro-Ro Passenger Craft (A), (B) — Passenger craft, and those that also carry motor vehicles, built to the Rules and the IMO HSC Code for restricted operating weather.
• HSC Cargo Craft — Craft other than passenger craft that keep the main safety functions of unaffected spaces after damage to any one compartment.
• HSC Crewboat — Fitted to move industrial personnel between shore bases and offshore installations. It may carry cargo but is not a passenger craft.
• HSC (special purpose) — Special-purpose craft with approved arrangements and scantlings, with the service described, such as Special Government Services.
• xx m (or ft) Significant Wave Height — Craft built for limited service, below the standard values for the craft type, with the design wave height stated in the operating manual.
• ● AMS — For HSC craft and new high-speed wind farm support craft, a variant of AMS where propulsion engines, gears and generators are accepted on manufacturer and ABS Type Approval certificates.
• HHP and SHHP — High and Super High Holding Power anchors, as above.
• IP — The craft complies with the IMO Industrial Personnel Code.
• OE (Operational Envelope) — The structure was reviewed against a speed and significant wave height envelope, which becomes part of the operating manual.
• R2-N and R2-N+ — R2 redundancy with machines, propulsors and steering in longitudinally separated spaces, so a single transverse bulkhead failure cannot disable all propulsion. The “+” adds the ability to hold position in adverse weather after a failure.
• SH-DLA — SafeHull Dynamic Load Approach: enhanced structural analysis on top of the HSC Rules design.
• Wind-SC(A) and Wind-SC(B) — Wind farm support craft. The grade depends on gross tonnage, number of industrial personnel and domestic or international voyage; larger craft or more personnel on international trips get (B).

Light warships, patrol and high-speed naval vessels

• HSC Naval Craft, HSC Coastal Naval Craft and HSC Riverine Naval Craft — Naval vessels with a high speed-length ratio operating in littoral waters. Open-ocean voyages are limited by wave height; coastal and riverine versions have tighter wave and distance limits.
• DV Naval Craft, DV Coastal Naval Craft and DV Riverine Naval Craft — The same roles for displacement-type naval vessels with a lower speed-length ratio.
• AB (Weight, Range), BFP1, BFP2 and BFP3, NavalSafe(x) and UNDEX (Weight, Range) — The same blast, ballistic, naval-safety and underwater shock notations as for naval ships.
• OE, R2-N, R2-N+ and SH-DLA — The same operational envelope, longitudinally separated redundancy and enhanced structural analysis notations as for high-speed craft.

Yachting service

Built to the ABS Rules for Building and Classing Yachts.

• Yachting Service — Pleasure yachts with unlimited geographical range when voyages are planned with weather routing, with wave height restrictions of 4.5 m (operational) and 6 m (maximum).
• Yachting Service R — Restricted service: no more than 200 NM from a place of refuge, with lower wave limits (under 3.5 m operational, 4.5 m maximum). Voyages beyond 100 NM need weather routing.
• Commercial Yachting Service — Chartered yachts carrying no more than 12 charter guests and no cargo, which must also meet statutory requirements for commercial yachts.
• Passenger Yachting Service — Steel or aluminium yachts carrying 13 to 36 passengers and no cargo, built to the Marine Vessel Rules for class items and passenger yacht codes for statutory ones.
• (✠) AMS — Machinery notation for new commercial yachts and new yachts over 61 m, where propulsion engines, gears and generators are accepted on manufacturer and ABS Type Approval certificates.
• COMF(Y) and COMF+(Y) — Owner and guest comfort, covering whole-body vibration and noise. COMF+(Y) adds stricter vibration criteria, including motion sickness.
• HHP and SHHP — High and Super High Holding Power anchors for yachts.

Barges, river craft and underwater vehicles

Barges (ocean services)

Built to the ABS Rules for Building and Classing Steel Barges unless stated.

• Barge — The base notation, for barges carrying the varied cargoes covered by the Rules.
• Accommodation Barge — Operates offshore as an accommodation barge, or carries accommodation in support of its work. The Circle P position mooring symbol is needed where anchoring is the only means of holding position.
• Barge ATB — Articulated tug barge: the tug is secured in the barge notch by mechanical means other than lines, and can push the barge or tow it by hawser. Tug and barge are classed separately and cross-referenced.
• (geographical limitations) Barge ITB — Integrated tug barge: the barge half of a mated tug-barge combination, classed as a separate vessel.
• Cable Laying — Unrestricted-service barges engaged in installing, maintaining and repairing telecommunication and power cables.
• Chemical Tank Barge (Ship Type X) — Carries dangerous chemicals. X is the IBC Code ship type: Type 1 for very severe hazards, Type 2 for appreciably severe and Type 3 for sufficiently severe.
• Container Barge — Outfitted to carry containers below deck.
• Container Deck Cargo Barge — A deck barge carrying containers above deck.
• Crane CRC — Barges with permanently installed cranes for work other than provisions and maintenance, certified under the ABS lifting appliance guide.
• Drilling Tender Barge — Carries personnel and principally supports an offshore drilling unit.
• Fuel Oil Tank Barge — Carries petroleum products with a flash point above 60°C.
• Fuel Oil or Chemical Tank Barge — Carries fuel oil or dangerous chemicals, but not at the same time.
• Fuel Oil and Chemical Tank Barge — Carries fuel oil and dangerous chemicals at the same time.
• Independent Tank Barge — Carries cargo in independent tanks with a working pressure below 2.06 bar.
• Pressure Tank Barge — Independent tanks with a working pressure of 2.06 bar or above.
• Liquefied Gas Tank Barge — Manned or unmanned barges carrying the liquefied gases covered by the IGC Code.
• Oil Tank Barge — Carries petroleum products with a flash point at or below 60°C.
• Oil or Chemical Tank Barge — Carries oil or dangerous chemicals, but not at the same time.
• Oil and Chemical Tank Barge — Carries oil and dangerous chemicals at the same time.
• Tank Barge — Carries liquid in bulk.
• OSR-S1, OSR-C1, OSR-S2 and OSR-C2 — Oil spill recovery barges. S versions are outfitted for recovery and C versions are built for it but not outfitted. Types 1 are for oil of unknown flash point; types 2 are for flash points above 60°C.
• Pipe Laying — Unrestricted-service barges installing subsea pipelines.
• Wind IMR — Barges installing, maintaining and repairing offshore wind turbines, possibly with equipment for piling, jackets, towers, nacelles or blades.
• ✠AMS-NP — Thruster machinery on non-propelled units, used only for short field moves of up to 12 hours in daylight, built to the Rules for self-propelled units.
• HDC(P, Locations) and HLC(ρ, Tanks) — Strengthening for heavy deck cargo loads above the Rule basic minimum, and for heavy liquid cargoes with a specific gravity above 1.05.
• LNG Bunkering and LNG Bunkering, VRS — A barge arranged for regular LNG bunkering. VRS adds a vapour return system.
• (LNG) R — An LNG tank barge with a regasification facility installed.
• RB — Rebuilt: a barge of any length surveyed, analysed and repaired to keep working beyond its normal 20–25 year life.
• VEC and VEC-L — A vapour emission control system on oil or fuel oil tank barges, and (VEC-L) one also suitable for lightering.

Rivers and intracoastal services

Built to the ABS rules for steel vessels on rivers and intracoastal waterways.

• Barge, River Service; Chemical Tank Barge, River Service (Type I, II & III); Oil Tank Barge, River Service; Passenger Vessel, River Service; and Towing Vessel, River Service — Standard river-service notations for each vessel type.
• Berthed Passenger Vessel, River Service — Passenger vessels not intended for temporary mooring.
• Floating Dry Dock — A floating dry dock over 61 m (200 ft) long, built under ABS survey to the Steel Floating Dry Docks rules.
• Reinforcement A and Reinforcement B — Added protection against contact with locks, the river bottom and wear from working with other floating equipment, at two levels.
• Barge, Great Lakes Service — A geographical limitation for barges built for the Great Lakes and the St. Lawrence Seaway.

Underwater vehicles, diving systems and hyperbaric facilities

Built to the ABS Rules for Building and Classing Underwater Vehicles, Systems and Hyperbaric Facilities.

• Submersible, Passenger Submersible, Lock-out Submersible, Ambient-Pressure X Submersible and Ambient-Pressure X Passenger Submersible — Manned or occasionally manned underwater vehicles, facilities and diving simulators built to the full Rules. The variants separate ordinary, passenger-carrying, lock-out and ambient-pressure types.
• Lock-out Submersible G — Lock-out submersibles operated by the US government that meet Section 12 of the Rules and the related survey requirements.
• Air Diving System (P) and (F), Mixed Gas Diving System (P) and (F), and Saturation Diving System (P) and (F) — Manned or occasionally manned diving system components. Each system type is listed in a (P) and an (F) form.
• Diving Bell, Dive Control Station and Handling System — Underwater vehicles and support components built to the full Rules.
• Hyperbaric Facility, Hyperbaric Diving Simulator and Hyperbaric Reception Facility — Hyperbaric facilities built under ABS survey. The simulator and reception versions add their own subsection requirements.
• ADS and ADS System — An Atmospheric Diving Suit, a single-person suit with muscle-powered articulated arms that resists external pressure, and the suit with its support stands, platforms, handling system and control station.
• Underwater Habitat and Underwater Complex — Habitats and complexes that include pressure vessels for human occupancy.
• ROV, Class X; HROV, Class X; and ROV System, Class X — Tethered unmanned vehicles for observation, survey, inspection and construction (ROV), hybrid vehicles that can switch to autonomous mode (HROV), and a vehicle with its handling system and control station (ROV System). Available for Class III and IV units.
• AUV, X and HAUV, X — Untethered autonomous underwater vehicles, and hybrid AUV/ROV units, where X is the category Large or Extra Large.

Offshore Services, part 1: drilling, production and installation notations

Offshore units are classed under the ABS Rules for Building and Classing Offshore Units and related guides. Their class lines normally start with ✠A1 followed by the service notation.

Drilling and construction units

• Accommodation Service — An offshore unit mainly for accommodating more than 36 industrial personnel, excluding crew. The Circle P position mooring symbol applies where anchoring is the only means of holding position.
• Barge Drilling Unit — A barge-type, displacement hull drilling unit without propulsion machinery.
• Drillship — A ship-type displacement hull drilling unit with propulsion machinery.
• Column-Stabilized Drilling Unit — A mobile offshore structure that relies on the buoyancy of its columns for flotation and stability in all afloat modes. Used for drilling.
• Column-Stabilized Unit — The same type of structure used for operations other than drilling, production, storage or handling of hydrocarbons.
• Self-Elevating Drilling Unit — A hull with enough buoyancy to be moved to site, then raised above the sea on legs supported at the seabed. Used for drilling.
• Self-Elevating Unit — The same type of unit for operations other than drilling, production, storage or handling of hydrocarbons.
• Drilling Tender — Supports an offshore drilling platform. It can carry power supply, circulating pumps, storage tanks, drill pipe racks, casing, cement, storage space, living quarters and a helicopter landing platform.
• Construction and Maintenance Service — A unit mainly for construction and maintenance in support of offshore mineral exploration and production.
• Crane Service — A unit mainly for lifting heavy loads of 160 metric tonnes or more in drilling, production, construction or salvage work.
• Cable Laying Service — A unit mainly for subsea cable installation.
• Pipe Laying Service — A unit mainly for subsea pipeline installation.
• Wind IMR — A unit mainly for installing, maintaining and repairing wind turbines, including piling, tower installation and nacelle and blade installation.
• Liftboat — A liftboat built to the full ABS Guide for Building and Classing Liftboats, or equivalent.

Floating production, storage and offloading

• Floating Production, Storage and Offloading System (hull type) — Covers the hull, equipment, marine machinery, position mooring and production facility of an installation that processes, stores and offloads hydrocarbons.
• Floating Production (and Offloading) System (hull type) — The same, for an installation that processes and offloads hydrocarbons without storage capacity.
• Floating Storage and Offloading System (hull type) — For an installation that stores and offloads hydrocarbons without processing. An FSO receives oil from a nearby processing installation and does not connect directly to a well.
• (Ship-Type), (Column-Stabilized), (TLP) and (Spar) — Hull type descriptors added to the three systems above.
  • Ship-Type: a single displacement hull, ship-shaped or barge-shaped.
  • Column-Stabilized: surface-piercing columns, submerged pontoons and a deck on the column tops.
  • TLP: a vertically moored tension leg platform that keeps its mooring in tension through excess buoyancy.
  • Spar: a deep-draft vertical floating structure, usually cylindrical, moored to the seafloor.
• Floating Offshore Installation (hull type), Hydrocarbon — A floating installation with production facilities where classification of the topside facilities is not requested, but essential safety features and certain systems are approved by ABS.

Offshore installations

• Offshore Installation — The base notation for installations built to the ABS offshore rules. It is followed by the service, below.
• Offshore Installation, Hydrocarbon Processing — For hydrocarbon processing facilities.
• Offshore Installation, Hydrocarbon Production — For hydrocarbon production facilities.
• Offshore Installation, Electric Generating Plant (electric generating plant-export load) — For an offshore electric generating plant, with the export load stated.
• Offshore Installation, Offshore Pipelines — For subsea pipeline systems built to the ABS pipeline guide.
• Offshore Installation, Offshore Risers — For subsea riser systems built to the ABS riser guide.
• Offshore Installation, Chemical Processing — For chemical processing facilities.
• Offshore Installation, Metals/Ore Processing — For metals or ore processing facilities.
• Offshore Installation (Self-Installing Unit) — Added to Offshore Installation when machinery and safety systems of a self-installing unit are in the class scope.
• Floating Offshore Installation (Hull Type), Electrical Service Platform — Floating, site-specific electrical service platforms built to the ABS offshore substation requirements.
• Offshore Installation, Electrical Service Platform — Bottom-founded, site-specific electrical service platforms.
• OSS — Applies to the power supply, transmission, battery and distribution equipment on a platform intended solely as an offshore substation.
• Offshore Wind Turbine (Bottom-Founded) and Offshore Wind Turbine (Floating) — Offshore wind turbines built to the ABS guides for bottom-founded or floating turbines.
• RNA — Added to either wind turbine notation when the rotor nacelle assembly and tower meet ABS Type Approval requirements and the site-specific assessment shows loads and deflections are acceptable.
• Single Point Mooring — A system that gives temporary offshore mooring to visiting vessels through a hawser or yoke from a buoy or fixed tower.
• Single Point Mooring (excl. PLEM) — The same, with the pipeline end manifold or similar equipment exempted from class, provided the flow-control arrangement is documented to ABS.
• Spaceport (Recovery), Spaceport (Launch) and Spaceport (Recovery, Launch) (hull type) — Offshore spaceports built to the ABS spaceport requirements, with the hull type given as Barge-Type, Column-Stabilized, Offshore Installation or Self-Elevating.
• Subsea Mining (hull type) — Mining units built to the ABS subsea mining requirements, with the hull type given as Ship-Type or Column-Stabilized.
• Ⓔ*Circle E* — An alternative anchoring equipment standard for self-propelled mobile offshore units and liftboats.
• ABS MPD and ABS MPD-Ready — Drilling units with a classed managed pressure drilling system (MPD), or ready for MPD operations without the essential equipment physically on board.
• ✠AMCC and ✠AMCCU — Automatic or remote control and monitoring of non-propulsion machinery on offshore installations. AMCC is controlled from a local centralised station; AMCCU allows the machinery spaces to be periodically unmanned and controlled from a remote centre.

Offshore Services, part 2: gas terminals, mooring, fatigue life and well services

Offshore liquefied gas terminals

• Offshore Liquefied Gas Terminal — Terminals built, installed and commissioned to the ABS requirements for floating or gravity-based liquefied gas terminals, also used for offshore installations carrying an LNG processing facility. The notation is mandatory and is built from letters:
  • F Floating, G Gravity Based.
  • L liquefaction facility, O transfer of liquefied gas (offloading/loading), P gas processing facility, R re-gasification facility, S storage facility.
  • T terminal whose processing facilities are not classed.
  • The cargo is shown in brackets: LNG, LPG, LNG/LPG or Ammonia.
• F(…) PLSO and G(…) PLSO — Terminals that receive well gas, process it, liquefy gas and condensate, then store and offload it.
• F(…) ORS and G(…) ORS — Storage and offloading terminals with a re-gasification facility. They receive gas or ammonia from a trading carrier, store it, re-gasify it and discharge ashore.
• F(…) SO and G(…) SO — Storage and offloading terminals that receive, store and offload LNG, LPG or ammonia in a lightering operation.
• F(…) T and G(…) T — Terminals with processing facilities that are not classed.

Mooring, station keeping and access

• Â Circle M — The anchor, chain or wire rope the owner specified for position mooring were tested to the owner’s specification in the presence of a Surveyor. Placed after ✠A1.
• Ã Circle P — The anchor, chain or wire rope satisfy the ABS offshore rules for position mooring. Required for accommodation units, accommodation barges and large-accommodation pipe-laying or subsea OSVs when anchoring is the only means of holding position.
• (M-PL) and (P-PL) — Pre-laid mooring. (M-PL) means the mooring equipment carried on board was tested to the owner’s specification with a Surveyor present. (P-PL) means the equipment carried aboard gives the unit its positioning capability when hooked up to pre-laid components.
• TAM-PL and TAM-PL (Manual) — A pre-laid mooring system with thruster assist, giving automatic position control (TAM-PL) or manual control by an operator (TAM-PL (Manual)).
• TAM, TAM-R and TAM (Manual) — Combined mooring and thruster systems that can hold position and heading under owner-specified conditions. TAM does so automatically, TAM-R adds thruster redundancy, and TAM (Manual) uses manual control.
• NMOOR-JETTY — A jetty mooring system built to the ABS nearshore position mooring guide. A fatigue life and maturation year can be added, for example NMOOR-JETTY(20), 2044.
• OCC (Offshore Charging Connection) — Single point moorings fitted with charging stations that meet the ABS single point mooring rules.
• GRC(Type I or II, PS, or AS) — A permanently installed offshore access gangway with an ABS register, as for offshore support vessels.
• (N) — A mobile offshore unit on the Norwegian Continental Shelf built and surveyed to the ABS N-Notation guide.
• ✠CDS (N) — Drilling systems that meet the ABS drilling systems guide and the extra requirements for the Norwegian Continental Shelf.
• (Disconnectable) — With AMS, a floating installation with its own propulsion and a way to disengage from its mooring and risers to ride out severe weather or seek refuge.
• (Disconnectable-R) — A disconnectable installation restricted to a service area near its site, either “from site to designated port” or “from site to geographic area” defined by four latitude and longitude points.

Fatigue, life and site notations

• FL(number of years), Year — The design fatigue life of an offshore installation is at least 20 years, in 5-year steps, with the year the fatigue life matures. The same name is used for wind turbines, where it is mandatory.
• FLM(number of years), Year — A separate design fatigue life for the position mooring or station-keeping system, used where it differs from the hull. It is used for new constructions and for position mooring systems built to the ABS mooring requirements.
• SFA(number of years), Year — Spectral Fatigue Analysis was performed under the ABS offshore rules and fatigue guide, with a design fatigue life of at least 20 years.
• SFA(R number of years), Year — For converted FPSO, FPS or FSO vessels: spectral analysis was used to assess the expected minimum remaining fatigue life, shown after the letter R.
• RFL(number of years), Year — Remaining Fatigue Life for an existing vessel converted to an FPSO, FPS, FSO or floating LNG terminal, assessed and recorded.
• RFLM(number of years), Year — Remaining Fatigue Life Mooring for converted units or single point moorings where the mooring has a different fatigue life from the structure.
• HL(number of years) — A floating terminal’s structural design life exceeds 20 years and it can operate on site without drydocking, with increased nominal design corrosion values.
• LE (number of years) year — Life Extension. For a first extension of up to 5 years, instead of a new fatigue analysis, if modifications are class-approved, critical areas are re-examined with non-destructive testing and open items are resolved.
• DLA and DLA (S design return period) — Dynamic Loading Approach for FPSO hulls. The (S) form uses the site’s own wave environment, for example DLA (S100) for a 100-year return period.
• (S) site — Site-specific design. For ship-type installations, it means transit and site data were used instead of North Atlantic data. For other installations and floating wind turbines, it records the site conditions the design and strength criteria were built for. The site is named, for example Brazil Santos Basin.
• (S years) site — For floating terminals, the design return period of the site assessment, for example (S100) Gulf of Mexico for 100 years.
• (CI) site — A vessel converted to a floating production installation, with the site stated.
• MARGINAL FIELD (site) — A converted FPSO, FPS or FSO for a marginal field, drydocked every 5 years and intended for the named site for 5 years. The RFL notation may be omitted.
• Restricted Service, Restricted Service – Afloat Condition and Restricted Service – Elevated Condition — Offshore units not designed to meet full unrestricted service criteria. The owner must operate within the limits in the operating manual. It is not used for site-specific installations that already name their site.
• OHCM (Offshore Hull Construction Monitoring) — A mobile offshore unit or floating installation built under the ABS construction monitoring requirements.
• SLE (XX) — Service Life Enhancement for ship-type floating offshore units, with an extra slop tank (ST), extended underdeck coating in cargo tanks (UC) and a five-year structural review (5Y).
• Topside Modules — Optional: the topside modules of a ship-type installation or floating gas terminal comply with the ABS requirements.
• RBI(Hull), RBI(Mooring), RBI(Riser), RBI(Topsides Facility), RBI(Topsides Structure) and RBI(Fixed Offshore Platform) — An approved Risk-Based Inspection program for the named part of an offshore installation.
• BRZ and BRZ+ — Floating installations in Brazilian waters complying with the applicable Brazilian regulatory documents, listed in two columns of an ABS table (BRZ and BRZ+).

Drilling, safety, environment and well services

• ✠CDS, ✠CDS(WCS), ✠CDS(DSD), ✠CDS(DSC) and ✠CDS(DSP) — Classified drilling systems built and commissioned to the ABS drilling systems guide. The sub-designations narrow the scope: WCS well control system, DSD derrick systems (drawworks, hoisting, drilling and motion compensation), DSC drilling fluid circulation and DSP specialised pipe and tubular handling.
• ✠CSS – Production — Subsea production systems, equipment and components reviewed, built, installed and commissioned to the ABS subsea production guide.
• ✠AMS-NP — Machinery and systems of non-self-propelled offshore units built as for self-propelled ones, including thrusters for short field moves.
• ✠SM1 and ✠SM2 — Offshore mobile mining units. SM1 covers the subsea mining systems in Sections 5 and 7 of the ABS requirements; SM2 adds the additional systems in Section 6.
• ABS MPD and ABS MPD-Ready — Managed pressure drilling, as for the drilling units noted earlier.
• DOPP and DOPP+ — Dropped Object Prevention. DOPP means an approved prevention program. DOPP+ adds equipment designs meeting primary securing, secondary retention and equipment securing requirements.
• EFP-A1, EFP-A2, EFP-A3, EFP-M1, EFP-M2 and EFP-IA — Enhanced Fire Protection for offshore units. A covers accommodation areas (A3 adds Section 7 requirements for MODUs and installations), M covers machinery spaces, and IA covers the industrial area of MODUs and floating or fixed installations.
• ENVIRO-OS, ENVIRO-OS+ and EP2020+ — Environmental notations for offshore units, floating installations and liftboats under MARPOL Annexes I, IV, V and VI. The “+” adds ABS criteria for design, management systems and discharges. EP2020+ covers refrigeration systems using a refrigerant above GWP 2000 that otherwise meet the ENVIRO-OS+ conditions.
• HAB(MODU), HAB+(MODU) and HAB++(MODU) — Habitability levels for drillships, drill barges, self-elevating and column-stabilized drilling units.
• HAB(OS), HAB+(OS) and HAB++(OS) — The same habitability levels for TLPs, FPSOs, FSOs, spars and other fixed or buoyant installations.
• ✠IMP-EXP, ✠IMP and ✠EXP — Import and export systems built in full compliance with the ABS rules, as IMP-EXP for both, IMP for the import system alone or EXP for the export system alone.
• WI, WI-READY, WIR and WIR-READY — Well intervention on mobile offshore units. WI is riserless, WIR is riser-based, and READY means designed for such a system.
• WS and WS-READY — A well stimulation system fitted or designed for later fitting.
• Well Test and WT-READY — A well test system fitted or designed for later fitting. WT-READY can also be requested after a Well Test system is removed.

What changed in the March 2025 edition, and how notations combine

The March 2025 edition adds, retires and restructures a number of notations. It also introduces Appendix 1, which shows the minimum mandatory notations for six common vessel types.

Newly added notations

Retired notations

Appendix 1: minimum mandatory notations by vessel type

ABS notes that further mandatory notations may apply depending on the specific equipment fitted.

Closing note

A notation only has meaning against the Rule or Guide it points to, so owners and charterers should check the current ABS edition before relying on any entry here. This guide summarises each notation in plain words and does not replace the Rules.

Source

American Bureau of Shipping, List of ABS Notations and Symbols, March 2025 edition