The owner or Master of a towing vessel shall ensure tha……

单项选择题The irregular black line around a charted light such as Race Rock Light indicates that it is （）.

A.unwatched
B.surrounded by riprap
C.a minor light
D.constructed on an artificial island

单项选择题The horizontal flat surfaces where the upper stock joins the rudder are the（）.

A.rudder keys
B.rudder palms
C.lifting flanges
D.shoes of the rudder

单项选择题The grip of a joint represents the（）.

A.thickness of the connected members
B.diameter of the head
C.entire length of the rivet
D.diameter of the shank

单项选择题The fluke angle of an anchor system is the angle between the（）.

A.flukes and the shank
B.shank and the sea bottom
C.mooring line and the sea bottom
D.flukes and the shackle

单项选择题The fitting that allows a boom to move freely both vertically and laterally is called the （）.

A.swivel
B.lizard
C.spider band
D.gooseneck