US3911845A - Sailing hydrofoil craft - Google Patents

Sailing hydrofoil craft Download PDF

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Publication number
US3911845A
US3911845A US254190A US25419072A US3911845A US 3911845 A US3911845 A US 3911845A US 254190 A US254190 A US 254190A US 25419072 A US25419072 A US 25419072A US 3911845 A US3911845 A US 3911845A
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Prior art keywords
craft
hydrofoils
sailing
hydrofoil
fore
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Expired - Lifetime
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US254190A
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English (en)
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Gerald Herbert Holtom
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
    • B63B1/00—Hydrodynamic or hydrostatic features of hulls or of hydrofoils
    • B63B1/16—Hydrodynamic or hydrostatic features of hulls or of hydrofoils deriving additional lift from hydrodynamic forces
    • B63B1/24—Hydrodynamic or hydrostatic features of hulls or of hydrofoils deriving additional lift from hydrodynamic forces of hydrofoil type
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
    • B63B35/00—Vessels or similar floating structures specially adapted for specific purposes and not otherwise provided for
    • B63B2035/009—Wind propelled vessels comprising arrangements, installations or devices specially adapted therefor, other than wind propulsion arrangements, installations, or devices, such as sails, running rigging, or the like, and other than sailboards or the like or related equipment

Definitions

  • the present invention relates to sailing hydrofoil craft.
  • the design is such as to attempt to maintain the craft in as upright a condition as possible in order to achieve the best aerodynamic conditions for the sail or sails and to reduce the hull resistance to a minimum.
  • a craft uses a keel and/or ballast and a small craft may be assisted by the crew sitting out on the windward side, in order to obtain the best sailing condition.
  • the problem therefore was to provide a stable and practical craft which used hydrofoils in such a way as to attempt to maintain a sailing craft in a near upright condition whilst reducing immersed surfaces, ballast and weight to a minimum.
  • Those immersed surfaces which existed should present as low a beam or width in proportion to their length and the unnecessary provision of floats or bouyant hydrofoils on outriggers which only added to the bulk weight and drag should be avoided.
  • Retention meanwhile of well tried and conventional methods of manoeuvring when sailing into the wind would be retained and the craft tacked in a normal manner.
  • the present invention consists in a monohull sailing hydrofoil craft having hydrofoils mounted rigidly on outriggers either side of the craft at such a height above the load water line so that on a reach or tack the windward hydrofoil or hydrofoils is or are lifted clear of the water.
  • Such a craft has the advantage that the windward hydrofoil or hydrofoils do not counteract the effect of the leeward foils and that when the craft is tacked or wears the non-engaged hydrofoil hydrofoils are heeled into an active condition whilst the former leeward hydrofoil are lifted clear of the water.
  • the helmsman meanwhile can ignore the hydrofoils and concentrate on obtaining a correct trim of the sails or sails.
  • the craft may have the centre of pressure of the hydrofoils in substantially the same plane as the centre of effort of the sail or sails. This ensures that the craft is stable as regards steering and it may be possible with careful triming of the sail or sails for the craft to steer itself.
  • the hydrofoils may be formed with a substantially triangular shape mounted so that the apex of the triangle is downward, the side of the triangle opposite the apex being substantially parallel with the fore and aft designed water line. the two remaining sides being equal, and the apex angle being between and 1l0 and preferably
  • These triangular hydrofoils ensure that the greater the immersion, the proportionally greater the area of area of hydrofoil is engaged with the water and this helps to achieve a stable opposing moment to the heeling force due to the wind pressure on the sail or sails.
  • the hull may have a semi-circular cross-section below the water line and the curve of the semi-circle may extend above the water line to meet a deck.
  • This feature ensures that the immersed surface of the hull remains substantially constant with a variation of heel.
  • the hydrofoils are preferably shaped so that the leading edge is parallel with a fore and aft line of the craft, whilst the trailing edge is turned outboard at an angle of 5 to 2 /z to the fore and aft line. This feature assists stability in steering.
  • the outriggers may be slidably mounted in the hull of the craft, so that when the craft is moored or being transported the overall beam is reduced.
  • the hydrofoil area may be between 4 /2% and 10% of the sail area.
  • FIG. 1 is an elevation taken from the port side of a craft according to the invention
  • FIG. 2 is a cross-sectional view taken across the craft of FIG. 1, and
  • FIG. 3 is a plan of the craft shown in FIG. 2.
  • the drawings show a hydrofoil sailing craft having a hull 1 of length of 52 feet and a beam of 8 feet 9 inches being a scaled up version of a 20 feet 5 inches X 2 feet I 1 inches prototype.
  • On either side of the hull 1 are hydrofoils 2 mounted on outriggers 3.
  • the hydrofoil area is about 35 square feet.
  • the boat has a single bermudan main sail and foresail 5 and a conventional mast 6.
  • the hydrofoils 2 are mounted with a dihedral of 45 to 55 and maintained at that angle by struts 7 and 7a.
  • Struts 7 act from a point near the centres of area of the foils to a cross bar 7b between the outriggers 3.
  • the shape of the foils is triangular with the apex A downward and the side opposite the apex, being the upper side, mounted so as to be substantially parallel with the designed water line W;W,,.
  • the triangular shape of the foil has a leading edge 10 and trailing edge 11 of approximately equal length and the angle at the apex A is preferably about 100 but optionally between 90 and
  • the shape of the foil can be changed from a triangular shape which from experiment would seem to be necessarily isosceles in shape, to a right curved shape such as a semicircle.
  • the foils are slightly dished so that the leading edge 10 cuts the water at an angle parallel to the fore and aft line FA, whilst the trailing edge 11 trails at an angle of approximately 2 /z away from the fore and aft line FA, the prototype using an angle of about 5.
  • the centre of effort C of the sail 5 is in the same substantially vertical plane as the centre of pressure C of the port or leeward hydrofoil.
  • FIG. 2 it can be seen that the starboard or windward foil is out of the water so that it has no effect apart from its weight on the transverse stability of the craft. An angle of heel of 12 is obtained before the windward foil enters the designed water line.
  • the transverse stability is in the main due to a balance of the horizontal component P,,, of the hydrofoil righting force P,, acting in opposition to the horizontal transverse component F of the pressure acting on the sail through the centre of effect C,,, the components P,,, and F acting about the axis of rotation X.
  • the triangular shape of the foils ensures that with a greater value of F,,., a greater area of immersion of the foil is caused which proportionally increases the value of P,,, until equilibrium is again achieved.
  • the effect of the foils is such that listing angle (1) is small and the mast of the craft is maintained in a fairly upright condition, thus ensuring a good performance from the sail.
  • the bow foil 15 is arranged to be retractable for stowage and use in shallow water.
  • the rudder l7 and stem foil 16 is mounted on a horizontal pivot 18 so as to ensure that it may also be retracted or rather lifted clear of the water.
  • a snap pin 19 is provided so that if an obstruction is hit the rudder l7 and foil 16 may lift and not be damaged.
  • the rudder 17 is stearable about a vertical pivot 20 in a conventional way by means of a tiller 21 and wires 22 connected is a steering wheel 23 in the cockpit 24.
  • a forward steering position 25 is provided.
  • FIG. 2 there can be seen the arrangement for slidably mounting the outriggers 3 in the hull.
  • the hull is provided with glass reinforced plastic tubes laid up into the hull and a bulkhead so that the Outriggers 3 can slide 10 feet right through the hull so as to projectS feet 9 inches on the opposite side, thereby reducing the overall beam from 40 feet to approximately 20 feet.
  • a bracing wire 31 and stainless steel strip 32 are provided to strengthen the outriggers.
  • Sails for the 52 feet craft are anticipated as being approximately 380 square feet for the mainsail, l 10 square feet for the foresail with the addition of a further foresail area 90 square feet if required.
  • the hull is manufactured from glass fibre reinforced plastics material with P.V.C. rigid foam bulkheads.
  • a sailing craft comprising: a monohull with accommodation for a helmsman, outrigger means extending in an athwartships direction either side of the monohull, at least one port and starboard hydrofoil having a negative buoyancy characteristic mounted rigidly on the outboard end of the outrigger means, the leading edge of the port and starboard hydrofoils being shaped so as to be parallel with the fore and aft line of the craft, the entire lower surface of at least the trailing portion of each hydrofoil being disposed at an angle outwardly turned with respect to a fore and aft line, divergent in plan and downwardly convergent in an athwartships vertical plane to exert a righting moment on the craft when submerged during forward movement having a horizontal component acting in opposition to the horizontal component of the force of the wind on the sail, said hydrofoils being slightly dished between said leading edge said trailing portion, and said hydrofoils being mounted to position the lowermost extremities of both said hydrofoils substantially no lower
  • the sailing craft of claim 1 wherein the port and starboard hydrofoils are of a substantially triangular shape mounted so that the apex of the triangle downward, the side of the triangle opposite the apex being substantially parallel with the fore and aft designed water line, the two remaining sides being equal and the apex angle being between and 1 10 and preferably 4.
  • the sailing craft of claim 1 wherein the hull has a semi-circular cross-section at least amidships and below the water line.
  • outrigger means comprise port and starboard Outriggers slidably mounted in the hull of the craft, whereby the beam of the craft can be reduced when the craft is not sailing.

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  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • Ocean & Marine Engineering (AREA)
  • Jib Cranes (AREA)
  • Wind Motors (AREA)
US254190A 1971-05-17 1972-05-17 Sailing hydrofoil craft Expired - Lifetime US3911845A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB1522871 1971-05-17

Publications (1)

Publication Number Publication Date
US3911845A true US3911845A (en) 1975-10-14

Family

ID=10055328

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Application Number Title Priority Date Filing Date
US254190A Expired - Lifetime US3911845A (en) 1971-05-17 1972-05-17 Sailing hydrofoil craft

Country Status (6)

Country Link
US (1) US3911845A (de)
CA (1) CA959351A (de)
DE (1) DE2224059C3 (de)
FR (1) FR2138062B1 (de)
GB (1) GB1348698A (de)
NL (1) NL7206692A (de)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3987982A (en) * 1974-12-06 1976-10-26 Amick James L Wind-powered flying boat
US4164909A (en) * 1975-11-19 1979-08-21 Ballard James S Wind driven hydrofoil watercraft
US4556005A (en) * 1984-11-28 1985-12-03 Jackson Gregg B Boat with auxiliary steering apparatus
AU643424B2 (en) * 1988-09-16 1993-11-18 Deutsche Airbus Gmbh Yacht
US6210242B1 (en) 1999-10-13 2001-04-03 Harry Howard Pedal-powered watercraft
US20060163428A1 (en) * 2005-01-25 2006-07-27 Nattinger John R Flying sailboat

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IT1189741B (it) * 1986-04-04 1988-02-04 Rodriguez Spa Aliscafo a geometria controllabile
GB2220170A (en) * 1988-06-03 1990-01-04 Robert John Webster High speed sailboat
FR2659287A1 (fr) * 1990-03-09 1991-09-13 Launay Claude Vehicule nautique type trimarant.
FR2703975B1 (fr) * 1993-04-13 1995-06-30 Bergh De Alain Henri Jean Hydroptere a voile.
WO2016123639A2 (en) * 2015-01-28 2016-08-04 Bullock Norman Cyril Rex Sailing watercraft

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1356300A (en) * 1920-05-25 1920-10-19 Mcintyre Malcolm Sailing-craft
US1709219A (en) * 1927-10-12 1929-04-16 Hille Carl Sailboat
US2255046A (en) * 1939-10-16 1941-09-09 Walter S Diehl Seaplane wing float
US3295487A (en) * 1965-09-23 1967-01-03 Smith Bernard Hydrofoil sailboat
US3696772A (en) * 1970-10-06 1972-10-10 Allen O Sundelin Boat stabilizer-sailing rig

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1356300A (en) * 1920-05-25 1920-10-19 Mcintyre Malcolm Sailing-craft
US1709219A (en) * 1927-10-12 1929-04-16 Hille Carl Sailboat
US2255046A (en) * 1939-10-16 1941-09-09 Walter S Diehl Seaplane wing float
US3295487A (en) * 1965-09-23 1967-01-03 Smith Bernard Hydrofoil sailboat
US3696772A (en) * 1970-10-06 1972-10-10 Allen O Sundelin Boat stabilizer-sailing rig

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3987982A (en) * 1974-12-06 1976-10-26 Amick James L Wind-powered flying boat
US4164909A (en) * 1975-11-19 1979-08-21 Ballard James S Wind driven hydrofoil watercraft
US4556005A (en) * 1984-11-28 1985-12-03 Jackson Gregg B Boat with auxiliary steering apparatus
AU643424B2 (en) * 1988-09-16 1993-11-18 Deutsche Airbus Gmbh Yacht
US6210242B1 (en) 1999-10-13 2001-04-03 Harry Howard Pedal-powered watercraft
US20060163428A1 (en) * 2005-01-25 2006-07-27 Nattinger John R Flying sailboat
US7252264B2 (en) 2005-01-25 2007-08-07 John Ross Nattinger Flying sailboat

Also Published As

Publication number Publication date
GB1348698A (en) 1974-03-20
DE2224059B2 (de) 1974-08-15
DE2224059A1 (de) 1972-12-14
DE2224059C3 (de) 1975-04-10
NL7206692A (de) 1972-11-21
CA959351A (en) 1974-12-17
FR2138062B1 (de) 1973-07-13
FR2138062A1 (de) 1972-12-29

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