Spritsail
Edges:Luff Head Leech Foot
Corners:Tack Throat Peak Clew
Thespritsailis a four-sided,fore-and-aft sailthat is supported at its highest points by themastand a diagonally runningsparknown as the sprit. The foot of the sail can be stretched by a boom or held loose-footed just by its sheets. A spritsail has four corners: thethroat,peak,clew,andtack.The Spritsail can also be used to describe arigthat uses a spritsail.[1]
Historically, spritsails were the first Europeanfore-and-aft rigs,appearing inGreco-Romannavigation in the 2nd century BC.[2]
The rig[edit]
The luff of the sail is bound to the mast, but unlike thegaff rigwhere theheadis bound to a spar, this rig supports theleechof the sail by means of a diagonal spar or spars named asprit(/spriːt/).[3]The forward end of thesprit sparis attached to themast,with the after end of the sprit spar attached to thepeak.The sprit is steadied and controlled from the deck by a pair of wire vangs (/wæŋ/WANG) attached to thepeakof the sail. It is said to be the ancestor of the common gaff rig that evolved in 16th-centuryHolland.The foot of the sail may be bent to a boom, or be loose-footed and just controlled by its sheets.
Barges[edit]
The spritsail was best known from its use in theThames sailing barge,which employs two similarly sized spars to form the framework for the sail area. In a barge, the mast is stepped vertically in a mast case ortabernacle,whilst the sprit is suspended by chainstanliffs(standing lifts) from the hounds at the mast head at an angle of about 30° from vertical, with sprit to the starboard side of the mast.[4]The heel of the sprit is secured to the mast, by themuzzle,which allows the sprit the freedom to move laterally, nearly as far to each side as the shrouds. This enables the vessel toreach and run.[5]The instability caused by allowing such a weighty spar to extend too far away from the vessel's centreline, however, had to be borne in mind when designing hull and rigging. The peak of the sail is permanently attached to the head of the sprit, which is steadied by two sets of vangs.[6]
The spritsail rig was normally used without aboom.(The latter was usually found on fore-and-aft rigged vessels to keep the mainsail in an aerodynamically efficient shape.) Such loose-footed sails can also be found on gaff-riggedNorfolk wherriesand thebawleyclass of vessel. The spritsail was a feature of theCromsterwhere the ability to furl the foot of the sail and raise the sheets, made gunnery much more readily possible. The sail could still be controlled using the vangs.[7]
In a commercial vessel, the rig has the advantage of allowing a high stack of deck cargo and freeing the cargo hatch of obstructions when loading and unloading. The entire sail can be quickly brailed to the mast. The overriding advantage is safety in open water. Barges are unballasted and, if overpressed, will heel excessively and must be pulled to wind. The sheet will be eased and the aft end of a boom could drag in the water making the rudder ineffective and a capsize inevitable. The sheet of loose footed boomless barge is just released and control is regained.[8]The boom does not project outboard so that the vessel can pass through a narrow gap between moored vessels. Loose footed sails suffer fromsail twistwhich reduces their aerodynamic efficiency when sailing off the wind, which usually is not a commercial issue. It can be an advantage in light air. The vangs control the head of the sail which can be set so as to make use of the air above the wind-shadow of moored ships, warehouses and so on.[9]
This fine control of the sail without need for the crew to leave the deck, is achieved bybrailing up.Rather than lowering themainsail,it is gathered up against its own luff and head by means of lines calledbrails.This technique is an effective way of stowing the mainsail and gives fine control over the power obtained from the sail. In narrow channels, and in the lee of tall buildings the mailsail and mizzen are brailed and the bowsprit topped up, and she sails on topsail and foresail alone.[10]A gaff rig was far more suitable for heavy weather and long sea passages, but when a gaff rigged vessel drops the mainsail, the topsail cannot be used. The gaff, attached to the mainsail, is required aloft to set the topsail.[11]
However, the sprit rig means that the sail is stowed aloft and unreachable from the deck. It also means that the sail cannot easily be covered when it is stowed, and thus protected from the elements. But in any case, the crews of working vessels did not trouble with such dainty ways. In keeping with the general philosophy of working boats, all sails would therefore be traditionally treated with red oxide and other substances.[12]
The problem of the inaccessibility of gear was met in the Thames barge by stepping the mast in a tabernacle and using a windlass on the foredeck to strike the whole lot, mast, sprit, sails and rigging. The crew could sail under a low bridge such as atAylesfordorRochesterwithout losing steerage way. The windlass is below the tack of the foresail and the tackle at the foot of the forestay. In striking the gear, the foresail tack tackle had to be cast off. With the bridge cleared, the skipper and an extra man (the huffler) used the windlass to raise the mast.[13]
Dinghies[edit]
Modern use of the spritsail has also become more common through its use in theOptimist (dinghy)- this uses a boomed spritsail - in the case of which the sprit is tensioned by asnotterarrangement. This much simpler implementation sees the sprit anchored higher on the mast than on barges.
Leg of mutton spritsail[edit]
This is a sprit rig that uses a triangular sail, the luff is bent to the mast, and the one spar, the sprit-boom attaches to the clew of the sail. The fore end of the boom is tensioned (pulled tight to the mast) by use of a snotter chord. It is a precursor of the wishbone rig first popularised by windsurfers. On a Bolger 59 (square foot) rig, there is a 14'3 "luff, 13'7" leech and 9'0 "foot. [14]
Local boats[edit]
The spritsail is also commonly used in afore-and-aft rig(along with astaysail) on local traditional wooden boats of the west coast of Norway, most notably thefaeringvariant of theOselvar.[15]Traditionally, up until the second half of the 1800s, these boats used to be rigged with asquare rig.[16]
Square rigged ships[edit]
In an inconvenient piece of nautical ambiguity, the term "spritsail" also refers toa sail used aboard some square-rigged vessels,typically on vessels developed prior to the middle of the 19th century CE. Unrelated to the spritsail described above, it is an evolution of the ancient Greekartemonthat was eventually made obsolete by the evolution of more efficientheadsails.In the context of square-rigged vessels, the spritsail is a square sail set under thebowsprit;a "spritsail topsail" may be set above it, though this latter element of a square-rigged sailplan fell into disuse early in the 18th century CE.[17]In this form, in addition to carrying the spritsail itself the spritsailyard,mounted under the bowsprit abaft thedolphin striker,also often provided some lateral support for thejibboomand flying jibboom via theguyssupporting those spars.
See also[edit]
References[edit]
- ^Underhill, Harold (1938). "Glossary".Sailing Ship Rigs and Rigging(Second, 1958 ed.). Glasgow: Brown, Son and Ferguson. p. 114.
- ^abCasson, Lionel(1995): "Ships and Seamanship in the Ancient World", Johns Hopkins University Press,ISBN978-0-8018-5130-8,pp. 243–245
- ^Keegan, John(1989).The Price of Admiralty.New York: Viking. p.280.ISBN0-670-81416-4.
- ^March 1948,p. 224.
- ^March 1948,p. 234.
- ^March 1948,pp. 225, 234.
- ^"Duckworks - Boomed Vs Boomless".duckworksmagazine.Retrieved12 May2017.
- ^Lillistone, Ross."Duckworks - Boomed Vs Boomless".duckworksmagazine.Retrieved11 May2018.
- ^March, Edgar (1948).Spritsail Barges of Thames and Medway.London: Percival Marshall. p. 7.
- ^March 1948,p. 24.
- ^Roberts, Bob (2000).Coasting bargemaster: illustrated.Woodbridge: Seafarer Books. pp. 20, 21.ISBN0953818012.
- ^March 1948,p. 116.
- ^March 1948,p. 129.
- ^Routh, David (Shorty)."My favorite sail, the Leg-o-Mutton Sprit".duckworksmagazine.Archived fromthe originalon 2 November 2019.Retrieved5 May2017.
- ^no:Fil:Oselver.jpg
- ^Google Translate
- ^Anderson, R. C. (1927). "Peface". The Rigging of Ships in the Days of the Spritsail Topmast 1600-1720 (First, 1927 ed.). Portland, Maine: The Southworth Press. p. vii.
External links[edit]
- Web articleArchived2019-11-02 at theWayback Machineabout triangular 'Leg-o-Mutton' sprit sail rig.
- Video of sailing the OselvarA spritsail-rigged Norwegian traditional wooden boat.
- "The amazing Spritsail, a forgotten jewel".christinedemerchant.Retrieved23 April2018.