单项选择题
A.a messenger B.a stopper for nylon line C.a U-bolt for securing a cargo whip to the winch drum D.turns of twine around a rope end
A tackle by which the outer end of a boom is raised and...
单项选择题A tackle by which the outer end of a boom is raised and lowered is the topping（）.
A.boom B.lift C.raise D.tackle
A stopper used in securing the ground tackle for sea th...
单项选择题A stopper used in securing the ground tackle for sea that consists of a grab attached to a turnbuckle is a（）.
A.riding pawl B.buckler C.devil's claw D.locking ring
A splice that can be used in running rigging，where the ...
单项选择题A splice that can be used in running rigging，where the line will pass through blocks，is a（）.
A.short splice B.long splice C.back splice D.spindle splice
