At the 78th session of the IMO Maritime Safety Committee (MSC 78), the proposed SOLAS CH XII as drafted by the sub-committee on Design and Equipment (DE47) in March of this year, which required future bulk carriers to be of double side skin (DSS) construction, was rejected and the IMO ditched the plans to make double hulls mandatory as from 2006.

The proposal was originally discussed at MSC 76 and further considered by the Sub-Committee on Design and Equipment (DE 47) at its 47th session when proposing consequential amendments to SOLAS Ch. XII.
The discussion at MSC 78 was very heated, with some delegations wanting the DSS bulk carriers as an alternative to single side skin (SSS) ships of this type, while other delegations strongly argued for the DSS concept. A new FSA study had been sponsored and this document was presented at the meeting. A substantial number of delegations participated in the discussion, with an almost equal number of delegations for and against mandating DSS bulk carriers. In the end, the Chairman was forced to take a vote to get a clear decision. The voting resulted in a clear majority for not mandating DSS for bulk carriers in the future.
In its efforts to amend SOLAS Ch. XII, MSC 78 maintained its previous decision to keep the minimum distance between inner and outer skin on future DSS bulk carriers at 1000 mm.
Although new rules covering DSS bulk carriers that are more than 150 m i n length and carry solid cargoes with a density of 1,000 kg per m3 will still be developed, shipowners will retain the option of sticking with ships of single-skin design.
For shipowners that want to order DSS vessels, the flooding requirements will not be mandatory until the amended SOLAS CH XII comes into force in 2006 at the earliest. In the meantime, DNV can offer DSS bulk carriers or combination carriers with lengths of 150 m and above the additional class notations ES (D, S18, S20) or ES (D, S17, S18, S20) on a voluntary basis. ES means enhanced strength, D indicates Double hull, and S17, S18 and S20 refer to IACS unified requirements: URS17, Longitudinal strength of hull girder in hold flooded condition, URS18 Transverse bulkhead strength considering hold flooding and URS20 Allowable hold loading considering flooding. This information will be a part of the vessel’s class notation.

Roald Vårheim/Arve Myklebust

Date: 12 February 2008