When the water has large or breaking waves in stormy conditions.

Fixed ports that do not open which are placed in the deck or cabin to admit light.

A boat that has rolled so that she is lying on her side or even rolled completely over (can be caused by a sudden gust or squall). A boat with appropriate ballast should right herself after being knocked down.

The inside center strand of rope.

An instrument that, once established, cannot be modified or cancelled without the agreement of all parties concerned.

To unfold or unroll a sail. The opposite of furl.

Permanent pip iron ballast specially shaped and placed along each side of keelson. Name is sometimes given to any iron ballast.

The average level of the oceans, used when finding water depths or land elevations.

To let out a line or sail slowly; to slacken or relieve tension on a line; to take pressure off.

Rolling a vessel, that is slightly ice-bound, so as to break the surface ice around her. May sometimes be done when a vessel is lightly aground, but not ice-bound.

To go aboard the vessel; to put onboard a vessel.

A freight booking made by a skipper or freight forwarder to serve space but not actually having a specific cargo at the time the booking is made. Carriers often overbook a vessel by 10 to 20 percent in recognition that "windy booking" cargo will not act ...

In sailing, to be lifted by a wind shift that allows your boat to be lifted closer to the wind where by it allows you to sail a shorter distance to the next mark, buoy or finish line

Combination minimum pressure valve and check valve.

A wind shift that forces a boat to sail below its mean wind course.

The error in a compass reading caused by the heel of a boat.

An enterprise in which there is a risk of loss.

A machine employing two or more stages.

Cargo landed in excess of the quantity on manifest.

A spar used to prevent the spinnaker guy from fouling on the stanchions.