A canting keel is a form of sailing ballast, suspended from a rigid canting strut beneath the boat, which can be swung to windward of a boat under sail, in order to counteract the heeling force of the sail. The canting keel must be able to pivot to either port or starboard, depending on the current tack.
The traditional yacht keel performs four functions:
The traditional fin keel, pointing straight down from the boat, provides no righting moment when the boat is level. The heeling force of the wind on the sails is therefore not counteracted until the boat has heeled over by a certain amount, moving the fixed keel to windward of the centerline. The purpose of the canting keel is to allow the boat to sail closer to level which generates maximum speed, by swinging the keel to windward and developing an adequate righting moment to keep the boat's angle of heel closer to level.
With the canting keel handling the ballast functions, lateral resistance and steering can be managed separately with a foil (or pair of foils, either on each side or fore and aft), such as daggerboards. This allows for much quicker maneuverability than traditional keelboats, with about half the weight usually required for ballast.
The first patent for a canting keel device was granted by Douglas Beardy on May 8, 1900. [1]
The first yacht to have a canting keel was the "Fiery Cross" designed by Jim Young (New Zealand) in 1959. In this canting keel device, the lever was mounted inside the fin at an angle and at the top it was connected to a vertical shaft. When the shaft was twisted around its axis, a curved lever pressed against the inner walls of the fin and tilted it. [2]
A version of the technology was invented and patented by CBF Technology in the 1990s. The canting keel's first use in an offshore race was the 1991 Mini Transat on number 29 Fouesnant la Foret and then in the Vendee Globe of 1996-7 which Pete Goss completed in a 50 ft, Adrian Thompson-designed yacht named Aqua Quorum. Development of the yacht and the events of the Race are described in detail in Pete's subsequent book Close to the Wind. Subsequent use in major competition was in September 2004, when five boats using the canting keel in the Maxi Yacht Rolex Cup placed ahead of the previously unbeaten world champion Alfa Romeo. Alfa Romeo II , designed by Reichel/Pugh features a canting keel and fore-and-aft twin foils (CBTF).
A variation of the canting keel is the 3d keel invented by François Lucas in 1998, which allows movement in three directions (side to side, forward and aft, and side to side).
Originally used in large maxi yachts such as the maxZ86, canting keels are now beginning to appear in smaller boats such as the Open 60, and the VO70 and Volvo Ocean 65 [3] (Volvo Ocean 65) ocean racing classes, and the even smaller Schock 40 and Classe Mini. The Schock 40 owned by Tom Schock famously lost its keel and capsized, illustrating the fundamental problem with complicated keel design: without a keel, most boats cannot float upright.
The Volvo Open 70 class boats in the 2006 around-the-world Volvo Ocean Race are perhaps the most well known boats to use canting keels for ballast. While previous years' boats showed a few percent improvement in speed each race (the race is held every three years) the VO70 class are showing a 30% improvement in speed. The 6.5 ton ballast bulb, hanging over 16 feet (5 meters) below the water and capable of canting up to 40 degrees, produces a tremendous amount of righting moment (over 130,000 ft·lbf, or 176,000 N·m with the hull level), allowing the boat to reach speeds of over 30 knots.
The current canting keel technology is far from perfect. At least three of the seven boats in the 2006 Volvo Ocean Race, one of the first major long term races allowing canting keels, had problems with the keels.[ citation needed ] One area in particular, the plates sealing the opening through which the keel passes, are prone to leaks. Unlike a centerboard or daggerboard trunk, the opening for a canting keel must allow significant lateral motion, which requires sliding seals.
The boat movistar had problems on Leg 4 of the Volvo Ocean Race, 200 miles off Cape Horn, during the night on 2 March 2006. It sprung a significant leak when the sliding plates that covered the keel opening fell off in the middle of the night. This was a problem that had occurred earlier. movistar's aft keel pivot broke loose and began flooding the boat. They made repairs in Ushuaia on the Beagle Channel. [4] Later on, in Leg 7 the same problem occurred in the north Atlantic. This time the decision was made to abandon ship, and the crew transferred to ABN AMRO TWO. movistar continued to broadcast its position for several days, but an aerial search failed to find the vessel, and it was lost.
In the 2006/2007 Velux 5 Oceans Race (a single-handed, round the world race), the Open 60 yacht Hugo Boss, skippered by Alex Thomson, had to be abandoned in the Southern Ocean due to the snapping of the hydraulic rams that controlled the keel, which caused the catastrophic failure of the keel. When this failure caused the yacht to nearly capsize, the boat was abandoned; Thomson was rescued by fellow competitor Mike Golding. On 25 November 2006, the boat's Sat C transponder stopped transmitting. The abandoned hull was found washed up on the shores of Patagonia 9 years later. [5]
In December 2016, Wild Oats XI has retired from the 72nd Sydney to Hobart yacht race, citing a broken hydraulic ram. Race spokesman Bruce Montgomery said Wild Oats XI was unable to move its keel after a hydraulic ram broke. "It's the gear that operates its canting keel, which is the keel that swings under the boat," he said. [6]
There were rumors that the 2007 International America's Cup Class yacht Alinghi might have had a canting keel. This would have given Alinghi an advantage over its challenger for the 2007 America's Cup, unless the challenger, Emirates Team New Zealand, also had a swinging keel. The America's Cup Class Committee, chaired by Ken McAlpine, issued a ruling on 8 May 2007 which stated that canting keels and other movable appendages were specifically prohibited.
In recent years, canting keel devices have been proposed in which the drive is not a lever, as it was before, but something else. One of these devices is a canting keel with a chain drive, which is able to tilt the fin 90 degrees or more. The author of this invention is Boris Kuchukov. [7] The fin and ballast keel must be in the air when a yacht equipped with such a device is moving. In theory, this should increase the speed of the yacht.
Sailing employs the wind—acting on sails, wingsails or kites—to propel a craft on the surface of the water, on ice (iceboat) or on land over a chosen course, which is often part of a larger plan of navigation.
A sailboat or sailing boat is a boat propelled partly or entirely by sails and is smaller than a sailing ship. Distinctions in what constitutes a sailing boat and ship vary by region and maritime culture.
The keel is the bottom-most longitudinal structural element on a vessel. On some sailboats, it may have a hydrodynamic and counterbalancing purpose, as well. As the laying down of the keel is the initial step in the construction of a ship, in British and American shipbuilding traditions the construction is dated from this event.
A point of sail is a sailing craft's direction of travel under sail in relation to the true wind direction over the surface.
A centreboard or centerboard (US) is a retractable keel which pivots out of a slot in the hull of a sailboat, known as a centreboard trunk (UK) or centerboard case (US). The retractability allows the centreboard to be raised to operate in shallow waters, to move the centre of lateral resistance, to reduce drag when the full area of the centreboard is not needed, or when removing the boat from the water, as when trailering. A centreboard which consists of solely a pivoting metal plate is called a centerplate. A daggerboard is similar but slides vertically rather than pivoting.
Proas are various types of multi-hull outrigger sailboats of the Austronesian peoples. The terms were used for native Austronesian ships in European records during the Colonial era indiscriminately, and thus can confusingly refer to the double-ended single-outrigger boats of Oceania, the double-outrigger boats of Island Southeast Asia, and sometimes ships with no outriggers or sails at all.
A bilgeboard is a lifting foil used in a sailboat, which resembles a cross between a centerboard and a leeboard. Bilgeboards are mounted between the centerline of the boat and the sides, and are almost always asymmetric foils mounted at an angle to maximize lateral lift while minimizing drag. They are most often found on racing scows.
Ballast is used in ships to provide moment to resist the lateral forces on the hull. Insufficiently ballasted boats tend to tip or heel excessively in high winds. Too much heel may result in the vessel capsizing. If a sailing vessel needs to voyage without cargo, then ballast of little or no value will be loaded to keep the vessel upright. Some or all of this ballast will then be discarded when cargo is loaded.
The winged keel is a sailboat keel layout first fitted on the 12-metre class yacht Australia II, 1983 America's Cup winner.
A bulb keel is a keel, usually made with a high aspect ratio foil, that contains a ballast-filled bulb at the bottom, usually teardrop shaped. The purpose of the bulb keel is to place the ballast as low as possible, therefore gaining the maximum possible amount of leverage and thus the most righting moment. An example of a class of boats that use a bulb keel is the International 110 racing class, which uses a 300 lb (136 kg) cast iron bulb keel on a boat whose minimum racing weight is 910 lb (414 kg).
The International Offshore Rule (IOR) was a measurement rule for racing sailboats. The IOR evolved from the Cruising Club of America (CCA) rule for racer/cruisers and the Royal Ocean Racing Club (RORC) rule.
The Volvo Open 70 is the former class of racing yachts designed for the Volvo Ocean Race. It was first used in the 2005–06 race.
A sailing hydrofoil, hydrofoil sailboat, or hydrosail is a sailboat with wing-like foils mounted under the hull. As the craft increases its speed the hydrofoils lift the hull up and out of the water, greatly reducing wetted area, resulting in decreased drag and increased speed. A sailing hydrofoil can achieve speeds exceeding double and in some cases triple the wind speed.
A sailing yacht, is a leisure craft that uses sails as its primary means of propulsion. A yacht may be a sail or power vessel used for pleasure, cruising, or racing. There is no standard definition, so the term applies here to sailing vessels that have a cabin with amenities that accommodate overnight use. To be termed a "yacht", as opposed to a "boat", such a vessel is likely to be at least 33 feet (10 m) in length and have been judged to have good aesthetic qualities. Sailboats that do not accommodate overnight use or are smaller than 30 feet (9.1 m) are not universally called yachts. Sailing yachts in excess of 130 feet (40 m) are generally considered to be superyachts.
The 2005–06 Volvo Ocean Race was held between 5 November 2005 and 17 June 2006. Seven boats took part in the race and made ten stops in nine countries.
Wild Oats XI is a maxi yacht, most famous for being the former race record holder and a nine-times line honours winner of the Sydney to Hobart Yacht Race. Launched in 2005, she was owned by Bob Oatley and skippered by New South Wales Mark Richards, who founded Palm Beach Yachts Australia.
Forces on sails result from movement of air that interacts with sails and gives them motive power for sailing craft, including sailing ships, sailboats, windsurfers, ice boats, and sail-powered land vehicles. Similar principles in a rotating frame of reference apply to wind mill sails and wind turbine blades, which are also wind-driven. They are differentiated from forces on wings, and propeller blades, the actions of which are not adjusted to the wind. Kites also power certain sailing craft, but do not employ a mast to support the airfoil and are beyond the scope of this article.
The Ultimate 20 is a trailerable sailboat that was designed by Jim Antrim as a sportsboat first built by Ultimate Sailboats in 1995. It is a one-design racing keelboat recognized by the International Sailing Federation.
ICAP Leopard 3 is a 30-metre IRC maxi yacht owned and skippered by Helical Bar plc CEO Michael Slade, who has owned maxi yachts for over 22 years. She features a canting keel, water ballast and twin daggerboards amidships.
The Schock 23 is an American trailerable sailboat, that was designed by Steven Schock, with a wing keel designed by Finnish engineer Reijo Salminen and first built in 1999.
{{cite web}}: CS1 maint: archived copy as title (link)