Basic Philosophy of the Design

The Sunhawk family of boats is intended to expand the sport of sailing for kids of all ages, 8 to 80.  In recent years interest in sailing has diminished in some parts of the country as other sports have become more attractive to youngsters.  Modern children increasingly play sports which are faster and higher scoring than previously, but little progress has been made on high performance boats for kids. 

In the sailing world, games such as sailball and sailing frisbee are receiving more attention as interest in racing has fallen off.  However, the boats generally used by kids such as the Sunfish, Laser, Hobie Wave and others, lack the go-fast features which have been developed for high performance boats.  Thus even though the games are potentially fast and exciting, the boats used do not provide the performance needed. The Sunhawk technology can be used to convert such boats into ones which are much faster at low winds and more stable in high winds. 

Description

The Sunhawk anti-heeler apparatus is a product which improves the performance of single-handed and double-handed sailboats by providing an anti-heeling action so that larger sail areas and taller masts can be utilized, enabling higher speeds.  The apparatus can be mounted on a variety of small single-handed and double-handed monohulls and catamarans as well as some larger boats. 

The product consists of two outward canted, surface piercing hydrofoils, usually curved, and a pair of hydrofoil holders, one on the starboard side of the boat and one on port.  Each holder has at least two positions in which the hydrofoil can be set.  In one position the hydrofoil produces negative lift, and in the other lift is positive.  When on starboard tack, the starboard hydrofoil is set for negative life. Thus, when viewed from aft, the boat rotates clockwise, which counters the heeling force of the sail.  The port hydrofoil is set for positive lift which also rotates the boat counter-clockwise, thereby increasing the anti-heeling effect.  When on port tack, the settings are reversed.

Typical Operation

Normally the field of play in sailball is set so a boat traveling from one goal to the other is on a reach.  A Sunhawk sailboat is thus designed to perform optimally at this point of sail. The Sunhawk14SS has about twice the sail area as an ordinary Sunfish but uses a Sunfish hull.  It is therefore oversailed by ordinary standards and will go much faster than a Sunfish.  There are several modes of operation.  In very light winds, the hydrofoils are totally retracted, and the daggerboard is fully immersed.  In light winds, the hydrofoils are also not used, and the boat is kept nearly upright by the crew hiking to windward.  In moderate breezes, the crew hikes out, and the leeward hydrofoil is pushed down as far as is needed to prevent heeling.  In addition to providing anti-heeling action, the leeward hydrofoil provides lift, thereby lowering the apparent weight of the boat, reducing form drag and inducing planing .  In stronger winds, the leeward foil is further down, and the windward one is partly submerged, and in very strong winds the windward hydrofoil is even further down.  The hydrofoil positions are set at the leeway angle for the tack being used so conflict between leeway forces and lifting forces are avoided.  In very high winds the hydrofoils favor stability over minimizing drag.