There is plenty of（）at this area.

The towing light is a(n)（）.

The transmission of messages respecting the dangers specified is free（）cost to the ships concerned.

What does the term TO NAVIGATE WITH CAUTION mean?（）.

The radiotelephone safety message urgently concerned with safety of a person would be prefixed by the word（）.

What is the normal length of anchor cable used to anchor a vessel?（）

What is normally used to pass a mooring line to a dock?（）

The best method to stop a vessel from dragging anchor in a sand bottom is to（）.

To develop maximum anchor holding power，the optimum angle between the anchor’s shank and the mooring lines is（）.

Which is NOT a distress signal?（）