Lightweight Construction Applications at Sea

The LASS project – Lightweight construction applications at sea – aims at improving the efficiency of marine transport and increasing the competitiveness of shipping/offshore industry by using lightweight construction materials such as combustible composites and aluminium. A major obstacle for using lightweight materials at sea is the potential fire hazard induced by such constructions. For a long time, the use of materials other than “steel or equivalent” (i.e. non-combustible materials) have been prohibited for ship construction.

The new SOLAS regulation 17: “Alternative design and arrangements”, opens new opportunities for using other construction materials provided that equivalent safety can be demonstrated. No general methodology for proving equivalent safety exists and the development of such a methodology has been a main focus for the LASS project.

Six different objects have been studied within LASS:

• 24m troop carrying military vessel in aluminium, redesigned into a composite passenger HSC
• 88m high speed aluminium ferry redesigned with a composite superstructure
• 199m ro-ro car ferry redesigned with an aluminium deckhouse
• 188m steel ro-pax vessel redesigned with a composite superstructure
• 89m inland freighter redesigned with superstructure and hatches in composite
• 400t steel offshore living quarters redesigned using aluminium

The LASS project has been successful. New fire certified constructions have been developed and technical difficulties related to lightweight constructions have been solved. Weight reductions have been achieved in the range of 35-65%. A methodology for demonstrating safety equivalency in accordance with SOLAS has also been developed in co-operation with the EU project SAFEDOR. More advanced and lightweight materials will in most cases increase initial cost for ship construction but will also make it possible to increase pay load or reduce cost for bunker fuels. Cost analysis made within LASS for some of the studied objects has shown that the economical benefit might be substantial after only a few years of operation. On 31st October 2007, a full day seminar will take place in Borås (Sweden) and detailed project result will be given.