Inboard
More toward the center of a vessel; inside; a motor fitted inside a boat.

Intracoastal Waterway
ICW- bays, rivers, and canals along the coasts (such as the Atlantic and Gulf of Mexico coasts), connected so that vessels may travel without going into the sea.

Jacobs Ladder
A rope ladder, lowered from the deck, as when pilots or passengers come aboard.

Jettison
To cast overboard or off. Informal. To discard (something) as unwanted or burden some.

Jetty
A structure, usually masonry, projecting out from the shore; a jetty may protect a harbor entrance.

Kedge
To use an anchor to move a boat by hauling on the anchor rode; a basic anchor type.

Keel
The centerline of a boat running fore and aft; the backbone of a vessel.

Knot
A measure of speed equal to one nautical mile (6076 feet) per hour.

Knot
A fastening made by interweaving rope to form a stopper, to enclose or bind an object, to form a loop or a noose, to tie a small rope to an object, or to tie the ends of two small ropes together.

Latitude
The distance north or south of the equator measured and expressed in degrees.

Lazerette
A storage space in a boat's stern area.

Lee
The side sheltered from the wind.

Leeward
The direction away from the wind. Opposite of windward.

Leeway
The sideways movement of the boat caused by either wind or current.

Line
Rope and cordage used aboard a vessel.

Log
A record of courses or operation. Also, a device to measure speed.

Longitude
The distance in degrees east or west of the meridian at Greenwich, England.

Lubber's Line
A mark or permanent line on a compass indicating the direction forward parallel to the keel when properly installed.