The Main Spars

A mast is the vertical pole that holds the sails up. The boom is the horizontal pole at the base of the mainsail — it swings side to side as you change course. Watch your head around the boom during manoeuvres.

The two main sails on a typical cruising yacht:

Watch

The Three Corners of a Sail

Every sail has three corners. Learn these and you'll understand every instruction about sail trim immediately.

CornerLocation
HeadTop of the sail
TackFront bottom corner
ClewBack bottom corner

The Three Edges of a Sail

EdgeLocation
LuffFront edge (the edge closest to the wind)
LeechBack edge (the trailing edge)
FootBottom edge

When a sail starts to flap at the luff — that front edge — we say it's luffing. It means the sail is too far into the wind and not generating power. We'll use this a lot in the trim lesson.

The Control Lines

Lines (ropes, on a boat) have specific names depending on what they do. The ones you'll use most often:

On a boat, ropes only get called "ropes" when they're unattached. Once a line has a job, it has a name. You'll hear mainsheet, halyard, sheet, vang, outhaul — never just "the rope".

Further reading