International Maritime Organisation (IMO) has accepted improved shipbuilding standards aimed at passenger and cargo ships. The new construction rules, designed to increase a vessel's chance of surviving an accident, were agreed at the IMO's committee on stability and load lines headed by the Australian Maritime Safety Authority (AMSA). They will come into force following final approval in November and will apply to ships with keel laying after January 2009.

The vulnerability of passenger ships was demonstrated last November when the 2,398-gt Explorer (built 1969) sank in the Antarctic hours after hitting an iceberg. There were no fatalities. The cruise industry has been pushing for better survivability rules through its "safe return to port" initiative.

Statistical analysis showed that the survivability of vessels needed to be improved. All ships will have to be built with a double bottom unless it can be proved that a comparable level of safety can be achieved. Among the new rules is one concerning lubricating-oil circulation tanks, which must be kept a minimum distance of 500 millimetres from the keel line of the vessel to prevent the oil escaping in the case of a grounding leading to engine failure.

Guidelines for the crew will also advise on how to ensure a vessel survives in an accident. Explanatory notes for shipyards and designers are now being drawn up and will be included in a revision of the Safety of Life at Sea (SOLAS) convention, available from classification societies.