单项选择题
A.increase the towing hawser's catenary and provide more spring
B.reduce catenary，allow operation in shallower water，and to release one barge without breaking up the entire tow
C.enable one tug and its crew without any outside assistance to make up or break down the tow
D.provide rapid delivery of logs from the northwestern United States to Hawaiian sawmills
单项选择题 An “on-load” release system on a survival craft means the cable can be released（）.
单项选择题 An “atoll cloud” forming over an island due to heating of the land during the daytime would be which type? （）
单项选择题 An “ABC” dry chemical fire extinguisher would be LEAST effective against a fire in（）.