Important Nautical Terms

There are many nautical terms. To ensure you remain safe and knowledgeable out on the water, the team at S.E.A. Safe Boating have listed a few terms that are commonly used among boaters. It is good practice to use the correct terms. In addition to these terms, we also offer a safe boating class for boaters across the state of Connecticut. Contact our team to learn more or to register for a course today!

Abaft - Toward the stern
Abeam - To the side of the vessel
Astern - Toward the stern
Beam - Width of the boat at the widest point.
Bearing - Direction of an object from the observer.
Berth - 1. Bed on board a boat. 2. A position where the vessel is made fast to a dock.
Bilge - Lowest portion of a vessel inside the hull.
Bollard - Large strong fitting on dock, usually iron, used to fasten mooring lines.
Bow - Forward section of the boat.
Breakwater - Structure built usually of rocks to create a protective barrier wall from heavy seas.
Bulkhead - A vertical wall in the hull.
Burgee - Small flag to indicate the identity of a club or organization
Cast Off - Remove all lines from a vessel in preparation of departure
Channel - Navigable portion of a waterway usually marked with buoys.
Chart - Detailed map of the waterway including land and buoys
Chine - The intersection of where the topsides and the bottom of the hull meet.
Chock - U-shaped fitting on the deck to position a mooring line.
Cleat - Fitting to which mooring lines are tied.
Course - Direction vessel is to be steered.
Deadrise - The angle formed by a horizontal line at the keel and the angle of the bottom of the boat as it rises upward from horizontal.
Deviation - Compass error from pointing to magnetic north.
Dolphin - Small group of piles sticking out of the water fastened together for strength.
Draft - The vertical distance from the water line to the lowest part of the boat.
Ease - Let out line slowly while in control of it.
Ebb - Outgoing (toward the sea) flow of tidal current.
Fathom - Linear measurement of 6 feet.
Forward - Toward the front or bow of the vessel.
Freeboard - The vertical distance between the waterline and the top of the deck
Galley - Kitchen on the vessel.
Ground Swells - Waves that become shorter and steeper as they approach shore or shallow water.
Ground Tackle - Rode (chain and/or line), anchor and shackles (Anchor and gear).
Gunwale - Pronounced Gun-el. The upper edge of the side of the boat.
Head - The toilet on board the vessel.
Helm - Steering gear, i.e., wheel or tiller.
Hull - Test
Keel - Main structural member beneath the hull to provide steering stability and reduce leeway.
Knot - 1. General term for a hitch or bend in a line. 2. One nautical mile per hour.
Leeway - Sideways drift of a boat caused by wind or current.
Length Overall (LOA) - Length from the tip of the bow to the end of the stern not including anything bolted to the hull.
Line - Rope used on board a vessel.
MAYDAY - Radio distress call.
Midships - Near center of the vessel.
Moored - Anchored or tied to a dock or pier.
Mooring - A permanent anchor usually marked by a round mooring buoy.
PFD - Life preserver (Personal Floatation Device)
Pile - Pole, usually wood, driven into the bottom to be used to support a dock or to aid navigation.
Pitch - 1. Rise and fall of the bow as the vessel moves through the water. 2. The theoretical distance a propeller will advance forward in one revolution.
Port - Left Side of the boat facing forward. (PORT and LEFT both have 4 Letters)
Pulpit - Forward railing structure at the bow.
Quay - A wharf or pier parallel to the water’s edge for loading and unloading cargo.
Radar - Electronic system to determine the position of objects at night and in reduced visibility.
Rode - Line and chain connected to the anchor.
Roll - Alternating motion of a boat leaning alternately from port to starboard.
Saloon - Pronounced Sal-on. The main cabin of the vessel.
Scope - The ratio of length of anchor rode in use to the vertical distance from the bow of the vessel to the bottom of the water.
Screw - Propeller
Scupper - Drain holes in the deck.
Sea Anchor - Parachute shaped device used in deep open water to keep a vessel’s bow into the wind and waves and reduce drift.
Shipshape - Vessel kept well organized and in good working order.
Starboard - Right side of the boat facing forward.
Stateroom - Sleeping quarters for guest or captain.
Stem - The forward member of the hull
Stern - Aft section of the boat.
Stow - Put in proper place.
Stuffing Box - A through hull fitting for the propeller shaft or rudder post.
Superstructure - Cabins and other structures above deck.
Swell - Long large wave.
Tides - The vertical rise and fall of water caused by gravitational forces of the sun and moon.
Topsides - The sides of the vessel above the water line.
Transom - 1. The transverse part of the stern. 2. Vertical section at the stern.
Variation - Difference between true geographic north and magnetic north.
Vessel - Any craft used for transportation on the water.
VHF Radio - Very High Frequency radio used for communication.
Wake - Waves created by the passing of another vessel.
Wharf - A structure parallel to the shore for docking.
Windage - Wind resistance.
Windlass - A rotating drum for hauling in line (like anchor line).
Windward - The direction from which the wind is blowing.
Yaw - To swing or steer off course.

Reference: Chapman Piloting
Test Your Knowledge

After looking over these terms, read the below sentence and see if you have an understanding of basic nautical verbiage.

The operator yells back to you, “cleat that line on the right side.” If you are facing aft (toward the stern) you may cleat it off on your right side which is actually the left or port side of the boat. If he had said “cleat it on the starboard side” (the right side when facing forward) there would be no confusion.