Common tanker rules

Helping you understand their implementation

Frequently asked questions

Q. Why change a system that has been in place for more than 100 years?

A. Traditional prescriptive Rules were based on empirical experience. They tended to favour the side of caution and no explicit consistent safety goals for the rules were stated. Irrespective of this they worked well for many, many years. With the emergence of advanced structural and hydrodynamics computational methods, designers became able to improve designs significantly over the years while more precisely meeting the rule requirements. In this way designers have been able to optimise ship designs with respect to construction and operation.

In the environment of increased expectations to safety at sea, shipowners, charterers, authorities and underwriters questioned whether the class societies allowed for too much optimisation of ship designs. In particular they questioned whether the class societies were mutually consistent in approval of new ship designs considering the competitive environment between the class societies.

As the self-regulatory mechanism for the industry, class responded. In March 2001 ABS, DNV and Lloyd's Register jointly announced that they would work to establish common criteria for ship structural design, including hydrodynamic loads and corrosion margins for standard ship types, beginning with tankers. The IACS Joint Tanker Project (JTP) and the new Common Structural Rules for tankers are the culmination of that project.

The IACS Joint Bulk Carrier Project (JBP) is a comparable development, for double side skin bulk carriers, undertaken by BV, CCS, KR, NK, GL, RS and RINA. Following initial development and harmonization of these two "pilot projects", IACS Council intends to adopt the resulting Rules as IACS Common Rules for tankers and bulk carriers.

Q. When will the new Rules be available and will industry have an opportunity to comment on them?

A. The draft tanker Rules were released to industry for comment in mid-June 2004. The release was followed by a series of industry seminars in the principal shipping centres around the world to explain the new criteria in detail. The comment period was extended to December 31, 2004, in full cooperation with other members of IACS and the JBP. Consequently there is a new set of Rules, dated March 2005 incorporating all comments made by industry and changes resulting from further development. The schedule provides for printed publication of the final Rules in late 2005 with an effective date April 1, 2006. The Joint Bulk Carrier Project (JBP) Rules will follow a similar schedule.

Q. Will the tanker and bulk carrier rules be based on the same technical approaches and criteria?

A. The two projects started at different points and have followed different paths but IACS has recognized that the two projects must deliver a harmonized approach to the fundamental assumptions of hull design, particularly since the approach will also provide the foundation for possible future projects to establish common structural rules for other ships types such as containerships. They have progressed in parallel in order to proceed as quickly as possible. An ad hoc IACS Rule Technical Harmonization group has been established to address this key issue. Whilst there are distinct differences inherent between bulk carriers and tankers, some initial harmonisation between the bulk carrier and tanker rules will take place prior to publication. However, further harmonisation work and consideration of the feedback from Industry into the continuous updating of the rules will remain IACS priorities after initial implementation.

Q. Will the text of the Rules be the same for all societies and therefore will the result, i.e. the scantlings, be the same?

A. From the outset, the JTP has worked from the basic assumption that, for the new Rules to achieve their stated objective of eliminating the competitive element from the establishment of structural standards, the text must be identical and the application of the rules must result in common scantlings.

Q. Are the new Rules based on those of any one society?

A. The new tanker Rules have been developed from first principles. The experience of each of the three societies has been taken into account. The central issue was an agreement, at the outset, that no society would be required to accept a standard that would be less than that currently required under each society's existing rules.

Q. Does that mean that a tanker built to the new Rules will be heavier than existing approved designs?

A. The ships will be more robust. Whether this will be achieved through a more fatigue-resistant design, through an increase amount of steel or a combination of these will depend on the preference of the designer as well as of the ship design under consideration. Generally it is to be expected that some increase in steel will result.

Q. The new Rules are expected to take effect from April 1, 2006. Does that mean they will apply to ships that had been previously ordered but for which the keels will not have been laid? Will it apply to options for sister ships that an owner may hold with a yard that are not exercised until after the April 1 date?

A. The new Rules are expected to apply to ships contracted for construction between shipbuilder and shipowner from April 1, 2006 onward. The applicability terms are defined in IACS PR29, available from the IACS website. JTP recognizes the commercial implications for both owners and shipyards of the new Rules. These must be balanced by the need to begin designing and building ships based on the common rules as expeditiously as possible once the new standards have been agreed.

Q. Will the common Rules replace individual society's existing software systems for design evaluation such as ShipRight or RulesCalc?

A. No. There is no intention, at this time, to develop common application software. However it is emphasized that the rules behind the software will be common. Instead the individual societies will decide which tools they will use to assess future designs.

Q. How will the new common Rules be maintained in the future so that they take account of in-service experience and new technologies?

A. These details have not yet been finalized. However feedback and rule enhancement is a continuous process, individually conducted by each society. It is expected that the common Rules will be maintained and updated by IACS, based on experience and feedback obtained by all IACS Societies.

Q. Is it likely, then, that IACS will introduce common survey Rules?

A. IACS is currently developing new Unified Requirements for the survey of new construction. It is also possible, depending upon the success of the new tanker and bulk carrier common rules, that consideration could be given to other ship types and possibly to the machinery rules.

Q. It is obvious that a great deal of money has been spent to develop these new Rules. What are the principal benefits that industry can expect as a result?

A. More robust ships that should be safer and more environmentally friendly. When properly operated and maintained, they should offer reduced through-life repair and maintenance costs. Furthermore, both shipowners and shipyards will benefit from having a single, commonly recognised standard that has been developed and will be maintained using the combined research capabilities and experience of all the IACS members.
Recent experience has underscored the reality that governments, the general public and an increasing number of industry representatives are questioning the shipping industry's current safety performance. This is despite the documented, constantly improving safety record of the industry. The reality is expectation to safety at sea is increasing among the stakeholders. Tanker owners, for example, now operate within a zero tolerance environment. Bulk carrier owners are dealing with the financial and operational implications of a raft of new IACS Unified Requirements designed to improve bulk carrier safety and reduce the number of incidents that threaten these aging vessels and their crews.
The more robust ships that will be built to the new Rules, designed for a 25 year life within the North Atlantic environment, will increase that margin of safety and influence the development of future designs.

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