A lit navigational aid such as a lighthouse that can be used at night or in poor visibility.

A signboard attached to a daybeacon to convey navigational information presenting one of several standard shapes (square, triangle, rectangle) and colors (red, green, orange, yellow, or black). Daymarks usually have reflective material indicating the sha ...

The operation of taking a sounding with the hand lead (to find bottom).

Atmospheric pressure as measured by a barometer.

Ice pack whose limits cannot be seen from ship.

The most common type of sail used today, a triangle-shaped mainsail defined by the mast and one horizontal boom perpendicular to the mast.

A means of purifying an air stream by using both gravitational and centrifugal forces.

(1) To adjust the sails for best advantage. (2) Fore and aft balance of a boat. If either the bow or stern is depressed, the vessel is said to be down by the bow or down by the stern. (3) To trim is to adjust. It does not just apply to sheets. You can tri ...

A keel that is narrow and deeper than a full keel.

A stream of vapor, gas or liquid coming out fast from a narrow orifice.

Nickname for a ship's cooper.

Is the property of a substance that gauges the potential or driving force for the flow of heat.

Board, bearing instructions, that comes to a wrecked ship with a life-saving rocket line.

To haul in until the line has a strain upon it.

Ribbon, yarn, or other lightweight material attached to rigging or sails to indicate wind action or direction. Proper use of the telltales can help sailors improve their sail trim.

The sudden heave of the ship.

A small free-moving submersible designed for exploring the ocean depths.

Said of wind when exactly ahead; and of another vessel when her fore and aft line coincides with observer's line of sight.

To haul in or bind something together in order to create more space.

Said of anchor when it is under ship's forefoot, and cable is nearly up and down.