An obstruction on a helodeck is any object that might present a hazard to the（）.

All ships（）suspected infectious disease on board should radio information to Port Health Officer.

Entries should be made in a Ro-Ro vessel’s cargo-securing device record book for（）.

A fishing vessel displaying the lights shown is（）.

A large basin cut into the shore，closed off by a caisson，and used for dry docking of ships is known as a（）.

A jack-up drilling unit elevated on the Outer Continental Shelf must have a fog horn that will sound（）.

A large valve，usually installed above the ram preventers，that forms a seal in the annular space between the pipe and wellbore or，if no pipe is present，on the wellbore itself is called the（）.

A fishing vessel casualty must be reported to the Coast Guard if it involves（）.

Please supply 200 tons of fresh water（）my ship.

An inert gas system on a tanker should be used to（）.