With growing global interest in gas as a major energy source and an increased order book for LNG carriers in particular, the technical specifications and safety standards of gas carriers and their operations have come in for growing scrutiny. These vessels are often portrayed unfavourably in the media and are not necessarily well perceived by the public. Some administrations and port state control organisations still target them for special inspection. Yet serious accidents affecting the ships and their cargoes have been few and the safety record has been good, according to the UK P&I Club's latest issue of Carefully to Carry, published in March.
The gas trade still employs relatively few ships - just under 1,000 carriers with over 1,000m3 capacity, compared with over 16,000 oil tankers. The five main vessel types are 336 pressurised LPG, 189 semi-pressurised LPG, 103 ethylene, 185 fully refrigerated LPG and 175 LNG. Of total capacity of over 35 million cubic metres, nearly 20.7 million are accounted for by LNG carriers, the leviathans of the gas fleet, just under 18 per cent by number but 59 per cent of carrying capacity. Given that LNG ships are exceptionally carefully designed, built and maintained, the weakest link in the chain is, as usual, human error by crew and pilots. Collision and grounding claims on all vessels are caused primarily by deck officer error. However, no less than five per cent of major claims are caused by pilot error with 14 per cent of collisions due predominantly to pilots.
“Carefully to Carry” discusses the carriage of liquefied gases in detail. It sets out the characteristics, strengths and weaknesses of each type of gas carrier and summarises why they are among the safest vessels on the high seas. It covers tank and containment systems, the closed loading system which prevents venting to atmosphere, automated loading, vapour return lines, the interconnections between ship and shore emergency shutdown systems, drydock safety, the growth in vessel capacity, IMO Codes, certification and training.