Recent Applications of Hydrofoil-Supported- Catamarans - Boat ...

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6With the foil system installed is e p = 0,229 at FnD = 3,82, which means animprovement of 33,8% in performance and a 26,8% speed improvement.A tandem Hysucat hydrofoil system was developed for the 22m Ferry “Sea Princess”for Waterfront Charters in Cape Town, RSA. The hulls were designed by “Bob vanNiekerk” for the former company T-Craft. Model tests were conducted in the towingtank at the University of Stellenbosch with various foil systems. The tandem foil systemgave the best result at the top speed of 34 knots and in the middle speed range around25 knots which is mainly used for sightseeing operations and allows most economicalcruising.The craft weighs fully laden (120 Passengers) nearly 60t and reached a top speed of 32knots. However, the propellers only absorbed 80% of the MTU Diesel engines of1000kW in the initial seatrials and the power ratio is e p = 0,19 at the Froude NumberFnD = 2,50 and a slenderness ratio L /? 0.33 = 5,27, (? being the volumetricdisplacement) making the Sea Princess a very efficient hull.The photograph of Figure 3. shows the Sea Princess during sightseeing trips around theCape Peninsula off Cape Town harbour.Figure 3: The Sea Princess
7A hydrodynamic stabilizer system was developed for the 21m Yacht “Kingcat” built byKingcat SA Shipyard in France on the basis of the Hysucat principle. The Kingcat hassymmetrical planing demi-hulls of the wave piercing type with moderate deep-V andextremely fine bows for reduced pitching in rough water. The hydrofoil system consistsof a mainfoil slightly forward the LCG position and a full beam sternfoil with attack anglecontrol spanning the tunnel width near the transom.With extensive mechanisation and computer control of all essential functions of the shipit weighs about 72t and therefore has a very low slenderness ratio L /? 0.33 = 5,13(heavily loaded hull !).It was found in the Kingcat model tests at the University of Stellenbosch, RSA, that thetandem foil system gives considerably improved resistance in the medium speed rangecompared to the Hysucat foil system with two rear struts, especially if the rear foil attackangle can be adjusted for optimised resistance at the hump resistance speed. Thehelmsman has total control over the trim angle at speed and can choose the best trimfor the top speed. The four MAN D2842 Diesel engines of 4 x 880kW driving 4 Lipswaterjets L J 43DL give the Kingcat a topspeed of 46 knots and fully laden 44 knots.It was a design condition that the frontfoil was not to be connected to the hulls belowthe waterline and the lift at speed is transmitted by two vertical struts fixed to thetunnel ceiling. The rearfoil is fixed on two shaft struts carried by the flange. The shaftstruts do not penetrate the hulls and even in a collision damage the watertight integrityof the ship is not affected. Figure 4. shows the Kingcat in the initial trial runs off SableD’Olonne on the French Atlantic coast.Figure 4: The Kingcat
Page 1 and 2: Newsletterwww.tsbp.state.tx.us FALL
Page 3 and 4: 3Making use of the so-called hydrof
Page 5: 5The avion type Hysucat foil system
Page 9 and 10: 9tunnel between the demi-hulls give
Page 11 and 12: 11Figure 6: The E-Cat foil at speed
Page 13 and 14: 13Another foil system was developed
Page 15 and 16: 15However, the trials in Chile only
Page 17 and 18: 173. CONCLUSIONThe hybrid of a cata
Page 19: 19Stumbo S. (2000), Wake Measuremen

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