Sailing Education

Parts of a Sailboat: A Visual Glossary

Hull, keel, rudder, mast, boom, mainsail, jib, halyards, sheets — labeled and explained for newer sailors.

Dmitry Shteyn
Dmitry ShteynWisconsin, USA · May 21, 2026 · 7 min read

The five parts every sailor names first

Almost every sailboat — from a dinghy to a 40-foot cruiser — shares the same essential anatomy. Learn these five parts and most other terms slot into place around them.

Hull and keel

The hull is the body of the boat that sits in the water. Underneath it, the keel (or a retractable centerboard on smaller boats) is a vertical fin that resists sideways motion when the wind pushes on the sails. Without a keel, a sailboat would slide downwind instead of moving forward.

Mast, boom, and rigging

The mast is the vertical spar that holds the sails up. The boom is the horizontal spar at the bottom of the mainsail, swinging across the boat as you tack or jibe. Standing rigging (steel wires) holds the mast up; running rigging (ropes called lines) controls the sails.

Sails

Most modern sailboats fly two sails: the mainsail behind the mast and the jib in front. Bigger boats add a spinnaker — a balloon-shaped downwind sail. The three edges of a sail are the luff (front), leech (back), and foot (bottom).

Rudder and tiller

The rudder is the underwater blade at the stern that steers the boat. It's controlled either by a tiller (a stick) on smaller boats or a wheel on larger ones. Push the tiller away from where you want to go — counterintuitive at first.

Cockpit and deck

The cockpit is where the crew sits and works lines. The deck is the walking surface. The bow is the front, the stern the back. Memorize those four and you can give directions on any boat.

Takeaways

  • Hull, keel, mast, sails, and rudder — five parts cover the whole boat.
  • Standing rigging holds the mast; running rigging controls the sails.
  • Tillers steer backwards from what feels natural; expect a learning curve.

Frequently asked questions

What's the difference between a keel and a centerboard?
A keel is a fixed, weighted fin attached to the hull. A centerboard is a retractable fin that pivots up into a slot, letting the boat float in shallow water. Big boats have keels; small dinghies usually have centerboards.
Why does the boom swing across the boat?
Because the mainsail must always sit on the leeward side of the wind to fill properly. When you tack or jibe, the boom swings to the new leeward side. Always duck.