Glance at IACS UR C6: Requirements for Lashing Software

The International Association of Classification Societies (IACS) has established specific requirements for lashing software under Unified Requirement C6 (UR C6). This software is a critical tool for ensuring the safety and stability of container stacks on seagoing vessels. According to the latest guidelines, all dedicated container ships must be equipped with approved lashing software that can accurately calculate the forces on container stacks and their securing device under various loading conditions. The software should assist the ship’s Master in determining whether the ship is loaded within approved limits, with a permissible accuracy deviation.

Background

Containers carry a vast array of different goods, from consumer goods such as shoes and electronic devices to chemicals and other raw materials. At the moment, the largest container ships can carry more than 24,000 containers. Containers lost overboard can be a serious hazard to navigation and safety at sea in general, in particular to recreational sailing vessels, fishing vessels and other small craft, as well as to the marine environment.

Hundreds of containers are lost at sea every year due to worsening weather conditions and poor maintenance. On average, there are somewhere between 700 and 1000 sunken containers annually. However, according to the World Shipping Council, 1,382 containers are lost at sea every year. In the 2020 – 2021 period, 3,133 containers were lost overboard, an increase of 400% compared to the previous period. This issue is often underestimated by the industry and requires urgent intervention.

The World Shipping Council and its members have initiated projects like the MARINE Top Tier study to understand and mitigate risks such as parametric rolling in following seas, which can lead to containers being lost overboard. These efforts are part of a broader commitment to enhance safety and reduce the environmental impact of container losses, which can pose risks to marine life and shipping lanes. The ongoing research and development of new safety protocols and technologies aim to further decrease these incidents, ensuring the safe and secure transport of goods across the world’s oceans.

IACS UR C6 – Requirements for Lashing Software are also important, on a similar line, minimum requirements for ensuring the safety of containers on seagoing vessels.

What is IACS UR C6 – Requirements for Lashing Software

The International Association of Classification Societies (IACS) has established specific requirements for lashing software under Unified Requirement C6 (UR C6). This software is a critical tool for ensuring the safety and stability of container stacks on seagoing vessels. According to the latest guidelines, all dedicated container ships must be equipped with approved lashing software that can accurately calculate the forces on container stacks under various loading conditions. The software should assist the ship’s master in determining whether the ship is loaded within approved limits, with a permissible accuracy.  An operation manual must accompany the software, detailing installation, function keys, menu displays, input and output data, and instructions for testing the software with test loading conditions. It’s also required that the software reflects the parameters of the lashing system as described in the Cargo Securing Manual, which is prepared in accordance with the Administration’s requirements.

These regulations are set to be uniformly implemented for ships contracted for construction on or after 1 July 2025.

What are the functional requirements of Lashing Software?

The functional requirements for lashing software as per the International Association of Classification Societies (IACS) Unified Requirement C6 (UR C6) are quite specific. Lashing software is an essential tool used onboard container ships should be:

• capable of calculating forces on containers and containers securing equipment for any loading conditions for each container stack;
• capable of indicating the respective permissible values in order to assist the master in his/her judgement on whether the ship is loaded within the approved limits.

The following parameters are to be also presented:

• summary of ship particulars such as IMO No., length, and breadth;
• summary of loading conditions showing relevant input parameters such as draught and GM;
• stack and container positions.
• actual stack weights verified against permissible stack weights;
• relevant properties of securing devices, including permissible loads;
• accelerations and other external forces such as wind containers are exposed to;
• listing of all calculated forces on containers and container securing equipment, and evaluation of compliance of the calculated forces with the corresponding allowable values;
• Graphical representation of each bay on deck and in holds;
• Provision of clear warning is to be given on screen and in hard copy printout if any of the allowable forces are exceeded;
• It must have a user-friendly feature to avoid incorrect data like negative draught etc.

Process of approval of Lashing Software

The lashing software is subject to approval by the Society. Societies are also known as classification societies and provide classification and statutory services and assistance to the maritime industry and regulatory bodies as regards maritime safety and pollution prevention, based on the accumulation of maritime knowledge and technology.  In other words, such organisation is also known as Recognised Organisations (ROs).

The Society, as applicable, is required to verify the type of approval of lashing software. Furthermore, verification of lashing software is not to be limited to the following:

• verification that the latest ship data has been used;
• verification and approval of the test loading conditions and their results;
• verification if requirements of functional requirements as listed above are satisfied;
• checking of proper installation, and verification of the instrument on board in accordance with the approved test loading conditions;
• checking the availability of the operation manual on board;
• verified with the approved test loading conditions in the presence of the Society Surveyor;
• Reapproval of lashing software in case of changes in the ship’s design or container securing arrangement.

What are acceptable deviations?

The accuracy of the computational results from the lashing software for the particular ship, on which the lashing software will be installed, is to be determined by using reference computation results deemed appropriate by the Society.

The tolerance of the accuracy of the results from the lashing software is to be below 1.0% of the allowable values. However, deviations may be accepted subject to review by the Society provided that there is a satisfactory explanation for the deviation and that there will be no adverse effects on the safety of the ship.

What are Survey requirements?

Each society ensures a safety regime with plan approval and Survey onboard. The survey of lashing software and associated onboard is concerned, at each annual and special survey, it is to be checked that the operation manual is available on board.

The lashing software is to be checked for accuracy annually by the ship’s Master by applying the test loading conditions. If the Society surveyor is not present for the lashing software check, a copy of the test loading condition results obtained by this check is to be retained on board as documentation of satisfactory testing for the surveyor’s verification at the next scheduled survey.

At each Special survey, this checking is to be done in the presence of the surveyor.

What are the requirements for the Lashing Software Operation Manual?

The IACS Unified requirement UR C6 requires the lashing software to have an operation manual. The manual is to be appropriate for the usage of the crew in terms of the language in which it is prepared. To ensure consistency, the language of the operation manual is to be the same as the language of the approved Cargo Securing Manual. Should it be considered necessary, it is to be translated into another appropriate language as well.

There are multiple details which are to be mandatorily required in the lashing software operation manual:

• a general description of the lashing software;
• installation;
• function keys;
• menu displays;
• input and output data;
• required minimum hardware to operate the software;
• instruction on testing the lashing software with the test loading condition;
• a list of all terms, definitions, error messages and warnings likely to be encountered by the user; and
• in the case of error messages and warnings, there are to be unambiguous user instructions for subsequent action to be taken in each case.

Summary of IACS UR C6

Here are a few points summarising IACS UR C6:

• The International Association of Classification Societies (IACS) has established specific requirements for lashing software under Unified Requirement C6 (UR C6). This software is a critical tool for ensuring the safety and stability of container stacks on seagoing vessels.
• Lashing Software should be approved by the Classification Society.
• Lashing software should have definite functional requirements.
• The lashing of the Software should be provided with the Operation Manual.
• The operation manual should be in the language in which the crew generally communicate
• Lashing Software should be surveyed during Annual and Special Surveys.

FAQ on IACS UR 6

What is the purpose of IACS UR C6: Requirements for Lashing Software?

The International Association of Classification Societies (IACS) has established specific requirements for lashing software under Unified Requirement 6 (UR C6). This software is a critical tool for ensuring the safety and stability of container stacks on seagoing vessels. According to the latest guidelines, all dedicated container ships must be equipped with approved lashing software that can accurately calculate the forces on container stacks under various loading conditions.

What is a requirement for the Lashing Software Operation Manual?

An operation manual must accompany the software, detailing installation, function keys, menu displays, input and output data, and instructions for testing the software with test loading conditions. It’s also required that the software reflects the parameters of the lashing system as described in the Cargo Securing Manual, which is prepared in accordance with the Administration’s requirements.

What are acceptable tolerances for Lashing Software?

The accuracy of the computational results from the lashing software for the particular ship, on which the lashing software will be installed, is to be determined by using reference computation results deemed appropriate by the Society.

The tolerance of the accuracy of the results from the lashing software is to be below 1.0% of the allowable values. However, deviations may be accepted subject to review by the Society provided that there is a satisfactory explanation for the deviation and that there will be no adverse effects on the safety of the ship.

What is the survey requirement for Lashing Software?

Upon installation, the lashing software is to be verified with the approved test loading conditions in the presence of the Society surveyor. It is to be checked that the operation manual for the lashing software is available on board.

During the annual Survey, it is to be checked that the operation manual is available on board. Furthermore, The lashing software is to be checked for accuracy annually by the ship’s Master by applying the test loading conditions. If the Society surveyor is not present for the lashing software check, a copy of the test loading condition results obtained by this check is to be retained on board as documentation of satisfactory testing for the surveyor’s verification at the next scheduled survey.

During the special Survey, the Society Surveyor check whether the operation manual is available on board. Also, lashing software is checked in the presence of the Surveyor.

When IACS UR C6 – Requirements for Lashing Software will be enforced?

This Unified Requirement (UR C6) is to be uniformly implemented by IACS Societies on ships contracted for construction on or after 1 July 2025.

What is the definition of “Contract for Construction?”

The “contracted for construction” date means the date on which the contract to build the vessel is signed between the prospective owner and the shipbuilder.

For more details refer to Safer and Cleaner Shipping – IACS