单项选择题
When anchoring a vessel under normal conditions，which scope of chain is recommended? （）
A.Four times the depth of water B.Two and one-half times the depth of water C.Five to seven times the depth of water D.Fifteen times the depth of water
单项选择题 When anchored，increasing the scope of the anchor chain normally serves to（）.
单项选择题 What type of stopper would you use on a nylon mooring line? （）
单项选择题 What is the purpose of the intermediate spring?（）
