Gaff rig
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This article needs additional citations for verification. (September 2012) |
Gaff rig[1] is a sailing rig (configuration of sails) in which the sail is four-cornered, fore-and-aft rigged, controlled at its peak and, usually, its entire head by a spar (pole) called the gaff. The gaff enables a fore and aft sail to be four sided, rather than triangular, and as much as doubles the sail area that can be carried by that mast and boom (if a boom is used in the particular rig). Additionally, for any given area of sail, the gaff rig will have a lower heeling moment than a triangular sail.[citation needed]
A sail hoisted from a gaff is called a gaff-rigged (or, less commonly, gaff rigged or gaffrigged) sail.[2][3]
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Description [edit]
Gaff rig remains the most popular rig for schooner and barquentine mainsails[citation needed] and other course sails, and spanker sails on a square rigged vessel are always gaff rigged. On other rigs, particularly the sloop, ketch and yawl, gaff rigged sails were once common but have now been largely replaced by the bermuda rig sail,[citation needed] which, in addition to being simpler than the gaff rig, usually allows boats to sail closer to the direction the wind is coming from.[citation needed]
The gaff is hoisted by two halyards:
- The throat halyard hoists the throat of the sail (the end closer to the mast) at the forward end of the gaff and bears the main weight of the sail and the tension of the luff[4].
- The peak halyard lifts aft end of the gaff and bears the leech tension. Small craft attach the peak halyard to the gaff with a wire span with eyes at both ends looped around the gaff and held in place with small wooden chocks, larger craft have more than one span. Peak halyards pull upwards, approaching the gaff at right angles[5].
Additionally, a gaff vang may be fitted. It is a line attached to the end of the gaff which prevents the gaff from sagging downwind. Gaff vangs are difficult to rig on the aft-most sail, so are typically only found on schooners or ketches, and then only on the foresail or mainsail.[citation needed]
A triangular fore-and-aft sail called a jib-headed topsail may be carried between the gaff and the mast[6].
Gunter-rigged boats are similar, smaller vessels on which a spar popularly but incorrectly called the gaff is raised until it is nearly vertical, parallel to the mast and close adjacent to it. More correctly the spar is called a yard, because historically the gunter rig is derived from lug rigs - where the spar from which the sail hangs is always called the yard - rather than from gaff rig; this is despite the similarity between a high peaked gaff rig and a gunter rig. On these rigs a topsail is never carried. Some gunter rigged boats use a single halyard to hoist the yard, but others use two; a throat halyard as in gaff rig, and a peak halyard running on a wire or rod gunter: one method of hoisting the latter type is to haul up the peak halyard first, so that the yard comes up to the mast but is not yet raised high enough vertically, then haul up the throat halyard, so that the yard slides upwards until the luff of the sail is taut.
Reefing a gunter rigged boat with a single halyard requires the sail to be fully lowered into the boat and (usually) the halyard repositioned on the yard or (rarely) the sail to be moved downwards along the yard. However some gunter rigged boats, certainly amongst dinghies, have an additional halyard from the end of the yard, to hoist the sail once the yard is hoisted; these are still technically gunter rigged but have borrowed some of the characteristics of the bermudian rig; essentially the yard is hosted fully and then left in position and regarded as a semi-permanent topmast, with the sail raised up or down it as required.
Another four-sided sail uses a spar with no halyard. One end of the spar, here called a sprit, is attached to the peak of the sail and the sprit is hoist until it tensions the head and leach and then the other end is secured to the mast near the tack with a Snotter. Such a rig is called Spritsails rig, and is considered a totally different rig.[citation needed]
Sailing characteristics (small craft) [edit]
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This section is written like a personal reflection or opinion essay rather than an encyclopedic description of the subject. (September 2012) |
The gaff rig generally has a lower Centre-of-Effort (CE) compared to a Bermuda rig,[citation needed] however, just as significantly, the CE is much further away from the mast.[citation needed] Often, gaff rigged boats have unusually long booms,[clarification needed] and this CE to mast distance is further increased. The effects of this distance can be quite dramatic, and dependent on the point of sail.
- Reaching with Gaff Sails
Whilst reaching, the CE being set further back, will encourage a small craft to bear up into the wind, i.e. strong weather helm. The boat builder can compensate for this at design stage, e.g. by shifting the keel slightly aft, or having two jibs to counter the effect. The Gaff-Cutter, is in fact a very popular sailplan for small craft. The helmsman, can reduce weather helm significantly, simply by sheeting out the mainsail. Sheeting out may appear to create an inefficient belly in the sail, but it is often a pragmatic alternative to having a heavy helm. A swing keel lifted halfway is the perfect treatment for weather helm on a gaffer. The usual adjustments to mast rake, or even bowsprit length may be made to a gaffer with persistent heavy weather (or lee) helm.
- Running with Gaff Sails
Running with a gaff-rig often requires a firm hand on the tiller. The CE of the mainsail may actually be overboard of the hull, in a stiff wind the craft may want to broach. Running goose winged with a jib boom would be ideal in moderate winds, but dropping the main entirely and running with jib alone may be prudent in stronger winds.
Gallery [edit]
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Gaff rigged schooner J. & E. Riggin. Her sails, from left to right, are: jib, staysail, gaff foresail, gaff mainsail, and, above that, a main gaff topsail
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A near-vertical gaff allows this Gunter-rigged boat to carry a triangular sail that is similar to the Bermuda rig
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Gaffelaar, by Johannes Christiaan Schotel, depicting both gaff and square-rigged boats
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Gaff rigged yachts race on Sydney Harbour, circa 1900
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Carmita, racing cutter
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Governor Ames, five-masted schooner
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Victory Chimes, National Historic Landmark
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Zaca, owned by Errol Flynn
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Traditional Dutch sailing barge
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The yacht of the VOC-Chamber of Rotterdam, by Jacob van Strij
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The schooner Rose Dorothea in 1907
See also [edit]
References [edit]
- ^ "The Gaff Rig Page". Retrieved 2008-10-05.
- ^ "N-gram comparison of 'gaff-rigged', 'gaff rigged', 'gaffrigged', 1900–2008". Google books Ngram Viewer. Google Inc. Retrieved 17 February 2013.
- ^ Michel, Jean-Baptiste; Shen, Yuan Kui; Aiden, Aviva Presser; Veres, Adrian; Gray, Matthew K.; Brockman, William; The Google Books Team; Pickett,, Joseph P. et al. (16 December 2010). "Quantitative Analysis of Culture Using Millions of Digitized Books". Science 331 (6014): 176–182. doi:10.1126/science.1199644.
- ^ Leather, John (2001). The Gaff Rig Handbook (second ed.). Woodenboat Books. p. 32. ISBN 0-937822-67-1.
- ^ Leather, John (2001). The Gaff Rig Handbook (second ed.). Woodenboat Books. p. 33. ISBN 0-937822-67-1.
- ^ Leather, John (2001). The Gaff Rig Handbook (second ed.). Woodenboat Books. p. 54. ISBN 0-937822-67-1.
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