A stopper used in securing the ground tackle for sea that consists of a grab attached to a turnbuckle is a（）.

A.over the bow or stern of a vessel
B.over the flat sides of a vessel
C.over the open water
D.over the dockside

A.block used only with manila rope
B.chock roller
C.hinged block
D.strong block used for short，sharp pulls

A.lower spring buoys into the water
B.find an anchor after the buoy has been lost
C.transfer a pennant wire to the anchor handling boat
D.clean chain as it is hauled into the rig