Boat Dimensions Terminology and Dictionary

Boating is an enjoyable process, but safely handling one can involve a lot of know-how. Between boat safety courses and talking with other sailors, you'll encounter plenty of terms along the way—some familiar, some not. If you're new to the game or need a quick refresher, we have the boat terminology guide for you!

Parts of a Boat

When getting to know your boat, there are plenty of different elements to learn about, each with their functions and names. First up is getting to know how to orient yourself on your boat, especially since standard everyday terms like "right" and "left" aren't in use while sailing.

  • Bow – The front of the boat
  • Stern – The rear end of the boat
  • PortSide – The left-hand side of the boat, when facing the bow
  • Starboard Side – The right-hand side of the boat, when facing the bow
  • Amidships – The central part of a vessel

"Port" and "starboard" tend to be some of the first terms that throw people off. One trick for keeping track is that "port" and "left" both have four letters and they go together. If you keep that in mind, remembering "starboard" becomes a process of elimination!

Also, it helps to remember these terms:

  • Forward – When moving forward, you are going towards the bow of the boat
  • Aft – When going aft, you are moving toward the stern
  • Topside – When moving from a lower deck of a boat to an upper one, you are going topside

Aside from orientation terms, knowing what's what on a boat will better help you understand where things are and better articulate which areas may need repairs over time. Key terms in this area are:

  • Hull – The body of the vessel
  • Gunwale – The upper edge of the vessel's side
  • Cleat – Metal fittings where you can attach ropes or cables while docking
  • Transom – The cross section of the stern, where an outboard motor can attach
  • Waterline – Where the boat's hull and the water's surface intersect
  • Keel – The lowest point in the boat's hull, which provides stability while in the water
  • Ballast – Any additional weight added to a vessel to provide stability
  • Chine – Where the hull sides intersect with the bottom of the boat
  • Helm – Area that contains the engine and steering controls of the vessel; the origin of this term is an English word that means "rudder," as that is what the helm controls
  • Mast – The vertical pole on a sailboat that supports the sails
  • Boon – On a sailboat, the horizontal pole extending from the bottom of the mast; by adjusting the boon, you move the sail to harness the wind
  • Rudder – A flat piece of wood, metal, or fiberglass at the bottom of the boat that helps steer; on a larger vessel, it may have a wheel for control, while smaller ships keep the mechanism on the aft
  • Fender – Generally a rubber tube that acts as a bumper to protect the ship from other vessels and docks
  • Anchor – An object that keeps the boat in place, either by weight or hooking to parts of the seabed
  • Outboard motor – A portable engine with its own motor attached to the outside of a vessel; used on smaller boats; it is possible to purchase used outboard motors

Locations on a boat also have different terms applied to them. Some common ones are:

  • Bilge – A compartment located in the lowest point of the hull
  • Aft – Area located by the boat's stern
  • Forward – Area located towards the bow
  • Berth – An area on a boat dedicated to sleeping
  • Casting Platform – an open deck on a fishing boat, often raised; used primarily for casting rods into the water
  • Cockpit – Recessed and semi-enclosed areas that rest lower than the surrounding decks
  • Deck – Exterior and flat surfaces means for people to walk and stand on
  • Head – The bathroom
  • Galley – Any kitchen or cooking area
  • Saloon – Social areas on larger boats; pronounced "salon," despite its spelling
  • Stateroom – Another term used to refer to bedrooms on a boat
  • Cuddy – Small, sheltered cabins on the boat

Thankfully, no matter what brand of vessel you get, be it G3 boats or otherwise, the parts will stay the same.


Boat dimensions terminology is important to learn for when you want to measure your boat and keep track of the dimensions or if you're shopping for a boat of a certain size. For the most part, length, width, and depth apply across different ranges. Important words in this category are:

  • Beam – The width of the widest point of the boat
  • Beam on the centerline (BOC) – The beam measurement as used for multihull vessels
  • Draft – The distance between the keel of the boat and the waterline; indicates the minimum depth of water the vessel needs to float
  • Air draft – The distance between the ship's waterline and the highest point of the boat; indicates the distance the vessel can safely pass under
  • Freeboard – The distance between the gunwale and the waterline
  • Complement – The full number of people necessary to operate a ship, not counting any passengers
  • Cube – A ship's cargo carrying capacity; the primary measurement is in cubic feet, hence the term; merchant ships tend to use the volume of cubic space as an indication of size
  • Length at the waterline (LWL) – The length of the ship when measured at the waterline; can differ from the maximum length of the ship
  • Ton – A unit of measurement often used to specify the size of a boat (generally larger vessels)

Nautical Terms

Aside from the parts of the boat, it's also useful to learn nautical terms for navigation reasons. Good terms to learn are:

  • Knots – The speed of one nautical mile per hour, which equals to 1.825 kilometers per hour
  • Bar – An area near the approach to a harbor or mouth of a river that is shallow and has sand, gravel, shingle, or sand near the bottom; often potentially dangerous to boats
  • Buoys – Floating containers used to mark channels, exclusion zones, moorings, and more; they use anchors hooked to the sea bottom to stay in place
  • Ebbtide – Used to describe the tide when it falls
  • Floodtide – Used to describe the tide when it rises
  • Enclosed waters – Ports or navigable waterways
  • Fairway – A navigable water channel
  • Open waters – A navigable waters that are not enclosed; also known as "ocean waters"
  • Give-way – Command to reduce speed, stop, or otherwise change course to give another vessel the right of way to navigate through an area
  • Planning – When a vessel is moving not through the water, but over the top of the water; happens when a boat picks up speed
  • Underway – A boat when it is not made fast to the shore and is also not at anchor; any time the boat is moving, whether by wind or motor
  • Astern – When a ship moves in a backward direction
  • Ahead – When a ship moves in a forward direction
  • Windward – The direction the wind is blowing
  • Leeward – The direction opposite to the way the wind is blowing; also known as simply "lee"
  • Awash – When water levels slightly cover the deck
  • Line – Sailor term of a rope
  • Course/Heading – The direction the ship is sailing
  • Bail – Throwing out water that has collected on the ship
  • Capsize – When a boat has overturned
  • Flank – The maximum speed of a ship

Getting a Grip on Terms

As you can see, sailing has enough terms to make a dictionary all its own. If you're new to boating and are looking for a vessel, the number of words can seem highly overwhelming. The good news is that you don't need to learn them all at once.

You want to start with the basics of understanding the parts of your boat and how to navigate, especially if you’re only using a personal watercraft. As you gain experience, you'll likely pick up words from other boaters and maybe even some slang.

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