A new type of ship propeller, to be known as the Pinnate and claimed to eliminate cavitation and noise, is being developed at the University of Stockholm. The propeller is characterised by an even number of blades and opposed blades are assembled in pairs on axles passing through the hub. These axles may be turned so that blade pairs are given a rotary reciprocating motion for each propeller revolution. The intention is to adjust pitch to the different inflow conditions occurring at the different blade positions throughout the revolution of the screw. Close to the top of the circle, where inflow is extremely shaded by the hull, pitch should be reduced to avoid the load increase that occurs in this position and gives rise to shock waves and cavitation. The opposite blade, simultaneously at the bottom of the circle, is given increased pitch through the action of the linking axle. A model with four blades has been tested in the cavitation laboratory at Kristinehamn by Karlstads Mekaniska Werkstad (KaMeWa). The results were satisfactory, cavitation being almost entirely eliminated. The prototype is now being tested at the National Swedish Shipbuilding Experimental Tank and first results have shown efficiency gains of approximately 5%. Order from: BSRA as No. 48,339.

  • Corporate Authors:

    Reed (Thomas) Industrial Press Limited

    36/37 Cock Lane, Saracen's Head Building
    London EC1A 9BY,   England 
  • Publication Date: 1978-1

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00178203
  • Record Type: Publication
  • Source Agency: British Ship Research Association
  • Files: TRIS
  • Created Date: Jul 19 1978 12:00AM