Ships – Sail or control means therefor – Reefing and furling
Patent
1995-04-11
1996-07-16
Swinehart, Edwin L.
Ships
Sail or control means therefor
Reefing and furling
B63H 904
Patent
active
055356931
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to the field of sail-boats.
More specifically, the invention relates to the rigging of sail-boats and especially spinnakers.
Spinnakers are well known in the field of sailing and are used to increase the sail surface area of boats in order to increase their speed under certain wind directions. Spinnakers take the shape of a light, very hollow triangular sail with a very large area. There are thus many shapes of spinnaker. Known spinnakers notably include radial, tri-radial and asymmetrical spinnakers. Radial and tri-radial spinnakers have a symmetrical shape along the longitudinal axis while asymmetrical spinnakers have a shape without a longitudinal axis of symmetry.
Spinnakers are generally made out of a very light synthetic fabric that enables them to:
be easily rigged,
be easily filled with wind,
occupy a relatively small volume when they are stowed.
Their domed shape when they are filled with wind furthermore enables them to pull the boat very efficiently.
Spinnakers are used essentially in downwind or quarterwind sailing conditions, but experienced helmsmen are capable of using them under less favorable wind directions.
However, it is relatively difficult to handle spinnakers. Indeed, their great surface area and shape prevents them being unfurled when the sail-boat is still. They can only be sent up when the boat is on the move.
Furthermore, the size of their surface area makes them unusable in heavy weather. Their large surface area indeed may prove to be dangerous in a strong gale.
The spinnaker therefore can only be used when weather conditions permit it. In this case, it is unfurled in front of the sail-boat with its halyard point being fixed to a spinnaker halyard brought to the end of the mast, with its tack being kept away solely by the force of the wind that sweeps into it in fixing it to a boom (which may also be used for a Genoa-sail) fixed to the front mast of the sail-boat, and by tautening its free end by means of a sheet.
One of the problems raised by spinnakers lies in their flimsiness. Indeed, they are made of a light and relatively flimsy material as compared with other sails and can therefore easily get torn in a gale.
Another problem inherent in sails of this type lies in the fact that they can easily get wound around the stay, especially in light weather during a failed maneuver or when the helmsman lets down a little too much and takes the wind out of the spinnaker with the main-sail. A stay such as this is formed by a cable designed to stiffen the mast in the frontward direction in an essentially longitudinal direction. This type of cable, which may be tensioned by means of a rigging device, is also used as a support either for the jib or possibly for a Genoa-sail. Thus, when the spinnaker is wound about this stay, it is relatively difficult to release it. For this, speedy action is needed before the cloth of the spinnaker gets torn in chafing against the stay. At the same time, care has to be taken not to luff or jibe in placing the spanker-boom manually over the false position and holding it in this position until the turns of the spinnaker get unwound by themselves. If such an operation proves to be fruitless, then a crew member must be sent to the top of the mast to unhook the halyard from the spinnaker and climb down along the stay, undoing the turns as he goes along. If despite such an operation, the spinnaker cannot be unfurled, then it must be decided to cut it with a knife.
Yet another problem raised by spinnakers lies in the fact that they have to be lowered as soon as weather conditions change and that, to do this, a crew member has to be sent to the front of the boat. Once the spinnaker has been hauled down, it has to be folded and stowed in a bag except when it has to be brought out again when conditions permit it. It will therefore be understood that the maneuvering of a spinnaker with a small crew or a single crew member is not easy.
2. Description of the Prior Art
In order to resolve th
REFERENCES:
patent: 113983 (1871-04-01), Crossman
patent: 3310018 (1967-03-01), Roberts, Jr. et al.
patent: 3789790 (1974-02-01), Crall
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