INDEPENDENT TANKSThese types of tanks are completely self-supporting and do not form part of the ship’s hull and do not contribute to the hull strength. Depending mainly on design pressure, there are three different types of independent tanks for gas carriers, Types A, B and CMARVS: – Maximum Allowable Relief Valve setting on a ship’s cargo tankIndependent tanks, type A (MARVS < 0. 7 bar)Independent tanks of type A are prismatic and supported on insulation-bearing blocks and located by anti-roll chocks and anti-flotation chocks. The tanks are normally divided along their centreline by a liquid-tight bulkhead; by this feature, together with the chamfered upper part of the tank, the free liquid surface is reduced and the stability is increased. When these cargo tanks are designed to carry LPG (at -50°C), the tank is constructed of fine-grained low-carbon manganese steel.The Conch design has been developed for carriage of LNG (at-163°C). The material for these cargo tanks has to be either...
