Posts Tagged ‘boat design’

PostHeaderIcon Dual-groove Head Foil

a slotted headstay system that contains two luff grooves to accommodate and provide continuous support for jibs or genoas that use boltrope. Usually made from aerodynamically shaped extruded aluminum or plastic and fitted over the headstay or forestay. A headsail is secured at the luff by sliding its luff tape/boltrope through a pre-feeder and then into the head foil feeder and up a groove. A dual-groove head foil allows for hoisting a second headsail in the second groove before dousing the first, so a boat can avoid running bare headed and losing performance. Harken’s brand is called Carbo Racing Foil. Schaefer Marine’s brand name is Tuff Luff. See also: jib peel.

PostHeaderIcon Spinnaker Pole Car

a device that allows a spinnaker pole’s inboard end to be raised or lowered to match wind and sailing conditions. The car travels on a vertically oriented track attached to the mast’s forward face. Either a pin stop or purchase system is used to control the car’s height. Also referred to as a mast car or pole slide.

PostHeaderIcon IMOCA

an acronym for the “International 60-foot Monohull Open Class Association.” Established in 1991 and recognized by ISAF since 1998, it is the governing body for the Ocean Racing World Championships, which include the Vendée Globe, the Route du Rhum, and the Transat Jacques Vabre. IMOCA is an open class, so anything is permitted unless the rules specifically prohibit it. See also: Equipment Rules of Sailing for 2013-2016 C.2.3. For more information, browse to

PostHeaderIcon DynaRig

a rig designed comprised of one or more masts, each with multiple isosceles trapeziodal-shaped sails supported by transverse horizontal spars or yards. The masts do not use shrouds or stays for support and the sails are not trimmed using sheets. Instead, the entire rig, including mast, yards and sails rotate to position the sails in the proper relation to the wind to generate lift. The DynaRig concept was originally developed by Wilhelm Prolss, a West German civil engineer. It was further refined by Dutch naval designer Gerry Dijkstra for the superyacht Maltese Falcon. Compare to: wingmast.

PostHeaderIcon Foil

any shaped surface designed to maximize lift while minimizing drag in a given range of conditions. Examples include centerboards, daggerboards, keels and rudders. A foil may be designed to operate in any fluid, such as air or water, though generally in yacht racing, only surfaces that operate in water are referred to as foils. Surfaces directed into airflow are referred to as sails. The exception is a head foil.

PostHeaderIcon Rudderpost

the vertically-oriented shaft on which a rudder is mounted. A tiller is attached directly to the rudderpost or a wheel is attached by means of cables or chains and pulleys. When a wheel is used, the rudderpost’s top is often accessible through a deck opening in the cockpit so an emergency tiller can be fitted in the case of wheel failure.

PostHeaderIcon Envelope

describes how sensitive boat performance is to helm movement; the amount you are able to steer to either side of a boat’s current optimal sailing angle without negatively affecting velocity made good (VMG). Depending on the conditions and sail shape, the envelope upwind can be as narrow as one or two degrees, or as wide as five degrees. Downwind, the envelope can be as wide as 25 degrees. Flatter headsails and spinnakers create a narrower steering envelope. A headsail with a rounder entry (from more headstay sag or more halyard tension) makes the steering envelope wider, but at the expense of pointing ability. The steering envelope is wider, and a boat has more “feel,” when heeled over. Also called the groove or steering groove.

About the author:
Bob Roitblat is an avid sailor, writer and professional speaker. If you have any comments about this blog, or you are interested in having Bob to speak at your club, contact the author here:

You may also be interested in Bob’s other blog, At The Helm, that is focused on the owners of small-to-medium sized closely-held businesses.

PostHeaderIcon Bermuda Rig

a mast and rigging configuration featuring a tall, triangular mainsail and a raked mast. The mainsail is set aft of the mast with its head raised to the top of the mast; its luff runs down the mast and is normally attached for its entire length; its tack is secured at the base of the mast; its foot controlled by a boom; and its clew attached to the aft end of the boom, which is controlled by a mainsheet. Also known as a Bermudian rig or Marconi rig. The later in reference to the inventor, Gulielmo Marconi, whose wireless radio masts the Bermuda rigs are said to resemble. The vast majority of racing monohull yachts are Bermuda-rigged sloops. See also: aspect ratio, B & R rig, fractional rig, and masthead rig.

PostHeaderIcon Cabin Sole

the bottom surface of the enclosed space under a boat’s deck. The cabin or saloon floor.

PostHeaderIcon Carbon Fiber

bundles of carbon-based filaments woven into sheets or tubes. When this fabric is embedded within plastic resin (i.e., epoxy) and formed into strong, lightweight material for such things as spars, structural members or hulls, the material is known formally as carbon-fiber-reinforced plastic (CFRP), but is often commonly referred to as carbon fiber. Carbon bundles may also be sandwiched between polyester film, such as Mylar, and formed into sails. See also: string sail. Compare to GRP.


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