Below is a list of some useful nautical terms.
ABOARD - On or within the boat.
ADRIFT - Loose, not on moorings or towline.
AFT - Towards the stern of the boat.
AHEAD - In a forward direction.
ASTERN - In back of the boat, opposite of ahead.
BATTEN DOWN - Secure hatches and loose objects both within the hull and on deck.
BOW - The forward part of a boat.
BOWLINE - A knot used to form a temporary loop in the end of a line.
BRIDGE - The location from which a vessel is steered and its speed controlled.
FIGURE OF EIGHT -
BULKHEAD - A vertical partition separating compartments.
BUOY - An anchored float used for marking a position on the water or a hazard and for mooring.
CABIN - A compartment for passengers or crew.
CAPSIZE - To turn over.
CAST OFF - To let go.
CATAMARAN - A twin-hulled boat, with hulls side by side.
CHART - A map for use by navigators.
CLEAT - A fitting to which lines are secured.
COURSE - The direction in which a boat is steered.
CURRENT - The horizontal movement of water.
DEAD AHEAD - Directly ahead.
DEAD ASTERN - Directly aft.
DINGHY - A small open boat.
FENDER - A cushion, placed between boats, or between a boat and a pier, to prevent damage.
FLARE - A distress signal.
FLOOD - A incoming current.
FORWARD - Toward the bow of the boat.
GUNWALE - Upper edge of a boat's sides.
HATCH - An opening in a boat's deck fitted with a watertight cover.
HEAD - A toilet on a vessel.
HEADING - The direction in which a vessel's bow points at any given time.
HULL - The main body of a vessel.
KEEL - The centerline of a boat running fore and aft.
KNOT - A measure of speed equal to one nautical mile (1,852m) per hour.
LATITUDE - The distance north or south of the equator measured and expressed in degrees.
LINE - Rope used aboard a vessel.
LONGITUDE - The distance in degrees east or west of the meridian at Greenwich, England.
MARLINSPIKE - A tool for opening the strands of a rope while splicing.
NAUTICAL MILE - One minute of latitude; approximately 1,852m - about 1/8 longer than the statute mile of 1,600m.
OVERBOARD - Over the side or out of the boat.
PLANING - A boat is said to be planing when it is essentially moving over the top of the water rather than through the water.
PORT - The left-hand-side of a boat.
RUDDER - A vertical plate or board for steering a boat.
SQUALL - A sudden, violent wind often accompanied by rain.
STARBOARD - The right-hand-side of a boat when looking forward.
STERN - The rear part of the boat.
TIDE - The periodic rise and fall of water level of a body of water due to the gravitational pull of the moon.
TILLER - A bar or handle for turning a boat's rudder or an outboard motor.
TRANSOM - The stern cross-section of a square sterned boat.
TRIM - Fore and aft balance of a boat.
UNDERWAY - When a vessel is in motion i.e. not moored.
WAKE - Moving waves, track or path that a boat leaves behind it, when moving across water.
WINDWARD - Toward the direction from which the wind is coming.