A boomkin, sometimes referred to as a bumkin or as a bumpkin, consists of an exceptionally strong and usually wooden spar

Spar

In sailing, a spar is a pole of wood, metal or lightweight materials such as carbon fiber used on a sailing vessel. Spars of all types In sailing, a spar is a pole of wood, metal or lightweight materials such as carbon fiber used on a sailing vessel. Spars of all types In sailing, a spar is a...

 that projects downwards and forwards over the main head rail of a traditional western sailing ship

Sailing ship

The term sailing ship is now used to refer to any large wind-powered vessel. In technical terms, a ship was a sailing vessel with a specific rig of at least three masts, square rigged on all of them, making the sailing adjective redundant. In popular usage "ship" became associated with all large...

, one on either side of the vessel. The heel of this spar is usually either butted against a knighthead or is bolted to it (bolting being more common from the end of the 18th century forwards). The outboard end of such a spar is designed with a neck to hold a single purchase block

Block (sailing)

In sailing, a block is a single or multiple pulley. One or a number of sheaves are enclosed in an assembly between cheeks or chocks. In use a block is fixed to the end of a line, to a spar or to a surface...

 through which the tack

Tack

Tack may refer to:* A type of cut nail, used in upholstery, shoe making and saddle manufacture* Horse tack, harness and equipment to allow horse-back riding* Tack , quick, temporary stitching intended to be removed...

 is passed.

History of development

From 1710 until 1850 the development of the boomkin in English sailing vessels generally proceeded thus:

• 1710-1730 CE: The first boomkins were usually square in cross section, and were generally only 6 feet (1.8 m) to 8 feet (2.4 m) in length. Their width was standardized at one inch per foot of length (a ratio of 1:12) and this was uniform throughout their length (that is, they did not taper at either end).

• 1730-1780 CE: Four changes in the shape of the boomkin took place during this time frame. It was lengthened, its inboard end was turned into an octagon in cross section rather than a square, its outboard end went from a square to a circle, and it began to taper somewhat so that it was 3/4ths its initial diameter at the tip.

• 1780-1805 CE: The only significant change during this time frame was that the boomkin often became circular in cross section from beginning to end.

• 1805 CE: From this date onward the inboard end was generally bolted to the knighthead and was made half-round in cross section. Also, an iron band was now introduced which could hold eyelets for the boomkin shrouds, usually three in number.

• 1825 CE: At around this time the boomkin regained its entirely rectangular cross section shape, and was usually one inch wider than it was high. It also gained an additional eyelet for the securing of a slip.

Over time the use of boomkins was extended to the stern

Stern

The stern is the rear or aft-most part of a ship or boat, technically defined as the area built up over the sternpost, extending upwards from the counter rail to the taffrail. The stern lies opposite of the bow, the foremost part of a ship. Originally, the term only referred to the aft port section...

 of the ship as well to provide an attachment point for a backstay

Backstay

On a sailing vessel, a backstay is the piece of standing rigging that runs from the mast to the transom of the boat, counteracting the forestay and jib...

 or the sheet

Sheet (sailing)

In sailing, a sheet is a line used to control the movable corner of a sail.- Fore-and-aft rigs:Fore-and-aft rigs comprise the vast majority of sailing vessels in use today, including effectively all dinghies and yachts. The sheet on a fore-and-aft sail controls the angle of the sail to the wind,...

 of a mizzen

Mast (sailing)

The mast of a sailing vessel is a tall, vertical, or near vertical, spar, or arrangement of spars, which supports the sails. Large ships have several masts, with the size and configuration depending on the style of ship...

.