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, but eventually came to refer to the entire back of a vessel. The stern side of a ship is indicated with a white navigation light at night.
Sterns on European and American wooden sailing ships have exist in two principal forms: the 1.) square or transom stern and the 2.) elliptical or fantail stern[1] and were developed in that order. The hull sections located before the stern are composed of a series of U-shaped rib-like frames set in a sloped or "cant" arrangement, with the last frame before the stern being called the fashion timber or fashion piece, so called for "fashioning" the after part of the ship.[2] This frame is designed to support the various beams that make up the stern. In 1817 the British naval architect Sir Robert Seppings first introduced the concept of the round or "circular" stern.[3] The square stern was an easy target for enemy ships and could not support the weight of heavy stern-chase guns. But Seppings' design left the rudder head exposed, and was regarded by many as simply ugly-- no American warships were designed with such sterns, and the round stern was quickly superseded by the elliptical stern which addressed the problems of the exposed rudder and the ungraceful shape of the round stern. The United States began building the first elliptical stern warship in 1820, a decade before the British began doing so.[3] The USS Brandywine became the first sailing ship to sport such a stern.
Transom stern edit
The term "transom" has two nautical meanings. A transom can refer to any of the individual beams that run across or "athwart" the hull at any point past the fashion timber; a transom can also refer specifically to the squarish surface that is the very back panel of a transom stern. In this sense, a transom stern is the product of the use of a series of transoms, and hence the two terms have blended.
Behind or "abaft" the fashion timber, the transom stern is composed of two kinds of timbers:
- Transoms - as previously mentioned, these timbers extend across the hull. The transom located at the base of the stern, and the uppermost of the main transoms,[4] is sometimes called the wing transom; the principal transom below this and level with the lower deck is called the deck transom; between these two are a series of filling transoms. Above the wing transom is the counter transom; next up is the window sill transom; above that, the spar deck transom.
- Stern timbers (also called stern frames) - timbers that are mounted vertically in a series, each timber typically resting or "stepping" on the wing transom and then stretching out and upward. Those not reaching all the way to the taffrail are called short stern timbers, while those that do are called long stern timbers. The two outermost of these timbers, located at the corners of the stern, are called the side-counter timbers or outer stern timbers. It is the stern timbers which give a square stern its rake.
The flat surface of any transom stern may begin either at or above the waterline of the vessel. The geometric line which stretches from the wing transom to the archboard is called the counter; a large vessel may even have two such counters, called a lower counter and a second or upper counter.[4] The lower counter stretches from directly above the wing transom to the lower counter rail, and the upper counter from the lower counter rail to the upper counter rail, immediately under the stern's lowest set of windows (called "lights"[5]).
Elliptical stern edit
In an elliptical stern, a set of straight post timbers or whiskers stretches from the keel diagonally on either side of the sternpost and rudder post, creating a sloped overhang at the back of the ship. Next, a series of cant timbers or cant frames are installed around these whiskers at a 45 degree angle until the curvature of the stern is complete. The finished stern has a continuous curved edge around the outside and is raked aft.
Other categories of stern edit
Other less-common types of stern include the canoe stern (also called a double-ended, parabolic, or cruiser-type stern) which curves from both sides of the hull out to a curved, canoe-like point; there is also the reverse stern, reverse transom stern, sugar-scoop or retroussé stern which is a kind of transom stern that is raked backwards (common on modern yachts, rare on vessels before the 20th century); the vertical transom stern or plumb stern is raked neither forward nor back but falls directly from the taffrail down to the wing transom; the rocket ship stern is a term for an extremely angled retroussé stern;
A bustle stern refers to any kind of stern (transom, elliptical, etc.) that has a large "bustle" or blister at the waterline below the stern to prevent the stern from "squatting" when getting underway.
History edit
Modern cruiseships edit
In modern cruise ships, the stern is frequently the location of the dining room, so as to provide uninterrupted views of the sea.
Modern warships edit
In modern warships, particularly cruisers and destroyers, the stern is usually where the helipad is located. The stern tends to be lower set when compared to other parts of the ship, and may contain a large caliber gun mount or missile magazines.The stern is usually subject to gunfire or cannonballs. Aircraft carriers typically use the deck space in the stern part of the ship for the recovery of incoming aircraft. Aircraft carriers may have aircraft elevators in the stern area to prevent interference of flight operations, which are launched from the bow. For submarines, both fast attack and ballistic missile, the stern is generally the location of the engine room and the motor room, if the submarine has one. If the submarine runs on nuclear power the stern may contain a heat exchanger and other parts associated with a nuclear reactor.
Gallery edit
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The transom of the Soleil Royal, by Jean Bérain the Elder -
The stern of the Dutch East India Company ship Amsterdam -
The stern of a modern sailboat (Tirion28) -
References edit
- ^ a b Estep, Harvey Cole (1918). How wooden ships are built. New York, NY: W.W. Norton. p. 59. OCLC 561361622.
- ^ Burney, William (2006) [1815], Falconer's new universal dictionary of the marine, Longon: Chatham Publishing, p. 457, ISBN 1861762046
{{citation}}:|first2=missing|last2=(help); Cite has empty unknown parameter:|lay-date=(help)CS1 maint: multiple names: authors list (link) - ^ a b Canney, Donald L. (2001), Sailing warships of the U.S. Navy, Annapolis, Maryland: Naval Institute Press, p. 66, ISBN 1537509905
{{citation}}:|first2=missing|last2=(help); Check|isbn=value: checksum (help); Cite has empty unknown parameter:|lay-date=(help)CS1 maint: multiple names: authors list (link) - ^ a b Hedderwick, Peter (1830), A treatise on marine architecture, containing the theory and practice of shipbuilding : with rules for the proportions of masts, rigging, weight of anchors, &c. including practical geometry and the principles of mechanics, observations on the strength of materials, hydrostatics, &c. With many valuable tables calculated for the use of shipwrights and seamen ; also the proportions, scantlings, construction, and propelling power of steam-vessels, Edinburgh: Published for author, p. 122, OCLC 220933246, retrieved 29 April 2011
{{citation}}:|first2=missing|last2=(help); Cite has empty unknown parameter:|lay-date=(help)CS1 maint: multiple names: authors list (link) - ^ Mondfeld, Wolfram zu (2005), Historic ship models, New York: Sterling Publishing Inc., p. 104, ISBN 1402721862
{{citation}}:|first2=missing|last2=(help); Cite has empty unknown parameter:|lay-date=(help)CS1 maint: multiple names: authors list (link)