MODERN MARINE JET PROPULSION

After outlining the history, over the past 25 years, of water-jet propulsion for small craft, with particular reference to the Hamilton system and its developments, the Author briefly discusses some of the fundamentals of good design for water-jet units. A modern jet unit of good design, with appropriate velocity/volume matching and applied within the scope of its design, will perform as well as the equivalent screw-propeller and have the advantage of absence of underwater appendages; it also offers excellent control at high speeds and during low-speed manoeuvring. High-speed craft of up to about 20 m will increasingly use water-jet propulsion as a natural choice, and its efficient employment is also exemplified in the somewhat larger Boeing Jetfoils and American Enterprise; both of these have Rocket-dyne Powerjet propulsion units. Water-jet propulsion may be advantageously used for patrol boats and high-speed craft and for many working boats and launches, but experienced advice should always be sought in the early stages of the project. The article includes some of the basic diagrams needed at the planning stages for a jet-propelled boat; the diagrams, which are briefly discussed, show (i) propulsive efficiency plotted against water-intake efficiency, (ii) optimum jet are plotted against water hp for different boat-speeds, and (iii) loss of propulsive-efficiency when the boat is operated at non-optimum conditions.

  • Availability:
  • Corporate Authors:

    Royal Institution of Naval Architects

    10 Upper Belgrave Street
    ,   United States 
  • Authors:
    • Davison, G H
  • Publication Date: 1979-11

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Filing Info

  • Accession Number: 00310889
  • Record Type: Publication
  • Source Agency: British Ship Research Association
  • Report/Paper Numbers: Technical Papers
  • Files: TRIS
  • Created Date: May 7 1980 12:00AM