单项选择题
Which tackle arrangement has the LEAST mechanical advantage（）.
A.Single whip B.Gun tackle C.Luff tackle D.Twofold purchase
单项选择题 Which mooring line prevents sideways motion of a vessel moored to a pier（）.
单项选择题 When lowering lifeboats in heavy seas，a good practice is to rig frapping lines（）.
单项选择题 What term indicates the line drawn at the top of the flat plate keel（）.
