This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. Find sources: "Bulb keel" – news · newspapers · books · scholar · JSTOR(October 2016) (Learn how and when to remove this message)
Flat Keel bulb
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.[1] 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).
Since bulb keels work best on long, thin keels or daggerboards, they are generally not used on sailboats intended for shallow waters, but are most often found on offshore racing craft. Daggerboards built like bulb keels are often referred to as "lifting keels", and they can be retracted into the boat to reduce the draft, and to allow the boat to be loaded onto a trailer. Lifting keels are also more likely to be found on craft built for speed, as a winch or a set of pulleys is required to provide purchase to lift the heavy keel.
Some boats with lifting keels go so far as to allow the keel to be canted side to side, allowing the bulb to be placed to windward to reduce heel in high winds; this type of keel is called a canting keel, and is used in the newest Volvo Ocean Race's Volvo Open 70 class yachts. It is also possible to shape the bulb into a horizontal foil, called a winged keel.
When the bulb protrudes past the leading edge of the keel, it is called a "T-bulb". It offers better performance (like required for racing), but is prone to hook into flotsam (like kelp or discarded fishing nets).
^Mayne, Richard (2016-09-15). The Language of Sailing. Taylor & Francis. ISBN 9781579582784. Retrieved 2016-10-11.
A bulbkeel 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...
Much modified by Mark Mills with new low V.C.G. lead keel without a bulb, and with laminar flow keel section with hollow trailing edge, swept back fractional...
68 m) with the standard fin and weighted bulbkeel. It was also sold with a shoal draft bulbkeel and lifting keel with twin rudders. The boat is fitted...
masthead sloop rig, an internally-mounted spade-type rudder and a fixed fin bulbkeel. It displaces 11,300 lb (5,126 kg) and carries 4,000 lb (1,814 kg) of...
controlled by a carbon tiller and a fixed carbon fibre fin keel with a weighted lead bulb. It displaces 3,902.18 lb (1,770 kg) and carries 1,565.28 lb...
and lays against the side of the hull. There is a 250 kg bulb, or weight, at the end of each keel that is shaped such that it remains hydrodynamic when lifted...
Southern Spars of Auckland, New Zealand, built her mast. She has a fixed bulbkeel. Launched in July 2002, she won the 2003 Giraglia Rolex Cup regatta, one...
mounted spade-type rudder controlled by a wheel and a fixed fin keel with a weighted bulb. It displaces 13,779 lb (6,250 kg) and carries 4,497 lb (2,040 kg)...
some cutting-edge boats use a bulb of ballast on a long, thin keel that can tilt from side to side to create a canting keel. This lets the ballast be placed...
a fractional sloop rig, a transom-hung rudder and a fixed fin keel with a weighted bulb. It displaces 1,950 lb (885 kg) and carries 900 lb (408 kg) of...
island. The Cape Fear monohull is believed to have lost its 6 feet (1.8 m) bulbkeel jeopardized[clarification needed] by a fluctuating sea state in the night...
fore and aft) keel with a 47,000 lb lead, squished ellipsoid bulb (known as the "geek") on the tip - instead of a classic or winged keel. While, the bow-rudder...
its smaller size and (except for A. fuegianus) by the less developed bulbkeels. Male: total length 7.9 millimetres (0.31 in); cephalothorax length 3...
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 a bulb at the bottom of an eight foot fin keel, the other could have a heavy hull with 20% ballast in a 2-foot-deep (0.61 m) full-length keel. The...
a skeg-mounted rudder controlled by a tiller and a swept, fixed fin bulbkeel. It displaces 2,300 lb (1,043 kg) and carries 1,145 lb (519 kg) of iron...
00 ft (2.13 m) with the keel extended and 2.42 ft (0.74 m) with it retracted, allowing operation in shallow water. The bulbkeel fully retracts into a recess...
2 ft) Engine type Outboard Hull appendages General BulbedKeel / Single Rudder Keel/board type Lifting Keel Rig General Sloop Sails Mainsail area 16.2 m2 (174 sq ft)...
retractable bulb fin keel. It displaces 1,600 lb (726 kg) and carries 600 lb (272 kg) of ballast. The boat has a draft of 5.67 ft (1.73 m) with the bulbkeel down...
Weetamoe was substantially modified, being given new hull contours and a bulbkeel. These modifications were not successful and were eventually reversed...
Allium carinatum, the keeled garlic or witch's garlic, is a bulbous perennial flowering plant in the family Amaryllidaceae. It is widespread across central...
Tranter wrote, "as the wind builds she heels initially, then the cast-iron bulbkeel stiffens her up. And just when you think you may need to reach for the...
Max. 1,000 mm (39 in) LWL Max. 1,000 mm (39 in) Hull appendages Keel/board type Bulbkeel Ballast Max 2.50 kg (5.5 lb) Rudder(s) Single Rig Rig type Sloop...
Global Information
