单项选择题
A.Serves as a backup for the main tow hawser in case of failure
B.Provides weight and flexibility to the total tow makeup
C.Lengthens the main tow hawser to keep the tow in step
D.Distributes the towing load
单项选择题 What could cause a significant difference between actual chain tension and the tension measured by the tensiometer? （）
单项选择题 We took usual steps:sounding the depth，reversing and stopping engine，paying out anchor and 60 fathoms of chain cable in the depth of 12 fathoms．The operation above is（）.
单项选择题 Wale shores would be used when drydocking a vessel with（）.