PROSPECTS FOR VERY-HIGH-SPEED HYDROFOILS

Severe hydrodynamic problems remain to be solved before hydrofoils can be designed to operate on the open ocean at speeds between 50 and 80 knots. These problems stem from two sources, cavitation and the free-water surface, complicated by the action of waves. Recently, a natural air venting phenomenon has been investigated which shows promise of being a very satisfactory mode for the operation of high-speed hydrofoils up to speeds at least as high as 80 knots. "Hyperventilation" is the complete breaking open to the atmosphere of a vapor or partially air-filled cavity, giving rise to an underwater planing condition. What was previously though of as a transient, extremely shallow submergence phenomenon has been shown to be a stable and predictable operating condition with a wide "window" encompassing speed, depth, angle of attack, foil section, and planform geometry. Model experiments also showed that the discovery explains a problem that has been encountered with present-generation subcavitating hydrofoil boats; that is, if a non-surface-piercing foil broaches the water surface and then reenters, it fails to pick up lift immediately and the hull consequently impacts the water heavily.

  • Availability:
  • Supplemental Notes:
    • Presented at the November 20, 1974 meeting of the San Diego Section of the Society of Naval Architects and Marine Engineers.
  • Corporate Authors:

    Society of Naval Architects and Marine Engineers

    601 Pavonia Avenue
    Jersey City, NJ  United States  07306-2907
  • Authors:
    • Conolly, A C
  • Publication Date: 1975-10

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Subject/Index Terms

Filing Info

  • Accession Number: 00127594
  • Record Type: Publication
  • Source Agency: Society of Naval Architects and Marine Engineers
  • Files: TRIS
  • Created Date: Dec 3 1975 12:00AM