During the dock repair, each sea valve must be disassembled, cleaned and ground well.Before it reassemble the sealing surface between the valve and the valve seat should be checked by ()

A . chief engineer B . surveyor C . the engineer D . the technique personnel of the shipyard

时间:2022-10-07 20:01:51 所属题库:船舶电气与船舶安全题库

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