What does daggerboard mean?
A daggerboard is a flat, often asymmetric board that slots vertically through a watertight casing — called a trunk or case — in the bottom of a small sailing boat. Lowered into the water, it acts like a shallow keel, resisting the sideways push of the wind so the boat can sail upwind efficiently; raised, it disappears into the hull, letting the craft float in very shallow water and reducing drag when running downwind. Unlike the hinged centreboard, which pivots up into the hull, the daggerboard is simply lifted straight out, making it simpler and cheaper to build but easier to lose overboard if not secured. The term belongs mainly to the world of dinghies, catamarans, and other small craft, where crews adjust it constantly to match wind direction and water depth. For anyone learning to sail small boats, understanding when to raise or lower the daggerboard is one of the first practical lessons on the water.
nounA movable, typically flat board inserted vertically through a slot (the trunk) in the hull of a small sailing boat, used to prevent leeway and improve upwind performance; unlike a centreboard, it is lifted out of the water rather than pivoted.
- A removable, vertical board slotted through the bottom of a small sailing craft to resist sideways drift and allow sailing closer to the wind.
"She raised the daggerboard as the dinghy ran downwind toward the shore."
"The sailing instructor reminded everyone to lower their daggerboards before tacking up the lake."
"Because the catamaran's daggerboards could be retracted, it floated in barely a foot of water."
The plural is standard for the object itself and is especially common for multihulls, which carry one daggerboard per hull.
"Both daggerboards were raised as the catamaran drifted over the sandbar."
Unlike most parts of a sailboat, a daggerboard can vanish entirely — lift it out and your dinghy skims over shallows where a keelboat would run aground.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of daggerboard
The word is a straightforward English compound of 'dagger' and 'board', describing the long, narrow, blade-like shape of the board that plunges into the water like a dagger into a sheath — the trunk being likened to a dagger's scabbard. 'Dagger' itself entered English in the Middle Ages from an uncertain Romance source, while 'board' derives from Old English 'bord', meaning plank or ship's side, a root it shares with nautical terms such as starboard and aboard. The compound arose with modern small-boat sailing, likely in the nineteenth or early twentieth century as lightweight dinghies adopted this simple alternative to the hinged centreboard.
Related word forms
How daggerboard is actually used
Primarily a technical term within dinghy sailing, small-craft design, and multihull contexts; rarely encountered outside nautical vocabulary. In American English the spelling 'centerboard' is standard for the pivoting counterpart, but the word 'daggerboard' itself is spelled identically in both regions.
Easily confused with daggerboard
A daggerboard lifts straight up and out of its slot, whereas a centreboard pivots on a hinge inside the hull.
A keel is a fixed structural fin built into a boat's hull, while a daggerboard is removable and can be raised or lowered by the crew.