Because it is simpler, the Model XL controllable-pitch propeller is claimed to be more reliable and durable than any of its predecessors. It is also lighter, which means that it places less strain on the stern bearing, thus lengthening the bearing's life. The propeller will be manufactured in a range of sizes for medium to large merchant vessels of 3,000 hp upwards - from large trawlers and tugs to the largest tankers and bulk carriers. Its design is also said to be suitable for warship propulsion. High-pressure rotating seals are avoided in the Model XL by using main high-pressure gear-type pumps mounted externally on the mainshaft. Rotating with the mainshaft, they are driven by pinions rolling around a stationary internally toothed gear ring inside the oil transfer box. The pumps supply oil from the oil transfer box to the pitch-changing mechanism in the hub via a hollow valve rod in the mainshaft. In this way, high-pressure oil doesn't have to be fed across mainshaft seals. A higher-pressure hydraulic system operates the pitch-changing mechanism. The oil flow rate of this system is about 25 percent of that for medium-pressure systems, and therefore components sizes are reduced, pipe diameters halved. The single-acting moving-cylinder servo-motor can be fitted conveniently in the hub between the blades. While the response of the Model XL to bridge control is reported to be sensitive and immediate, giving the high degree of maneuverability needed in confined waters, a load control system automatically changes the blades' pitch in open waters so that optimum power is obtained for the selected engine speed to suit prevailing conditions.

  • Corporate Authors:

    Transportation Development Agency Centre

    800 rene-Leveque Boulevard West, Suite 600
    Montreal, Quebec H3B 1X9,   Canada 
  • Publication Date: 1976

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00142639
  • Record Type: Publication
  • Source Agency: Transportation Development Agency Centre
  • Files: TRIS
  • Created Date: Dec 15 1976 12:00AM