Daggerboard

The shape of the daggerboard converts the forward motion into a windward lift, countering the leeward push of the sail.

[citation needed] A daggerboard is a removable vertical keel that is inserted through a "trunk" in the center of a vessel's hull, usually amidships.

Daggerboards are usually found in small sailing craft such as day sailers, which are easily handled by a single person.

The freedom of movement of dagger- and centerboards allows them to swing or slide up into the hull of the boat, which is advantageous when sailing in shallow waters.

[1] Daggerboards can be raised and lowered as needed but will generally be damaged if not retracted before impact with the bottom or with floating objects.

[2] Daggerboards also afford an opportunity to reduce drag when racing because they can be retracted when not needed (i.e. when sailing downwind or in very light winds).

[1] During a storm, daggerboards can help reduce the tendency of a small boat to tip over ("breach") due to waves.

[citation needed] If there is no wind and an outboard motor is being used, lifting the daggerboards will ensure the least drag.

The centerboard, daggerboard, or bilgeboard can be used as a platform upon which to stand, providing increased leverage, in the event the dinghy overturns via a capsize or turtle.

Daggerboards are often long and thin to reduce drag and increase effective lift, thus providing a better lift-to-drag ratio.