Power performance of planing boats with the effect of propeller selection and propeller guard design Public Deposited

http://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/47429c58j

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  • One of the unique problems associated with salmon gillnet fishing is of preventing the fouling of the boat's propeller in the net and associated fishing gear. Presently, the solution to this problem has been the addition of a basket type propeller guard which may produce a drag increase of 50 percent on small planing boats. Recognizing the need for a greater understanding of the interrelationship of boat drag and engine power to the effect of propeller selection and propeller guard design, this study analytically models planing boat power performance including the experimentally determined effects of nozzle type propeller guard design. The model predicts the drag forces acting on a prismatic planing hull and existing data on marine propeller performance is incorporated in the model such that the propeller shaft speed and shaft power for a particular boat propeller combination can be predicted. The model will also optimize propeller diameter. Three variations of nozzle type propeller guards were tested on a 16 ft. planing boat. The guards were a commercially produced outboard motor propeller weed guard, a short (1/D = 0.275) flow accelerating nozzle and the nozzle equipped with prerotation vanes. Computer modeling the effect of the three nozzle guards on the performance of a hypothetical 11500 lb. planing boat with a 265 Hp engine predicted that the top speed of the boat (with an optimum diameter propeller) would be 34.6 knots, with the weed guard 25.5 knots (a speed loss of 26 percent), with the flow accelerating nozzle 32.3 knots (seven percent loss) and the nozzle with vanes 27.4 knots (21 percent loss). The validity of the model is demonstrated by a comparison of the predicted values of propeller shaft speed and boat top speed, with an open propeller and the weed guard, to the actual values observed in operation of the 16 ft. test boat. Shaft speed predictions were within five percent and boat top speed predictions were within about ten percent of actual observations.
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  • description.provenance : Submitted by Madison Medley (mmscannerosu@gmail.com) on 2013-11-07T23:05:58Z No. of bitstreams: 1 LaddDanielM1976.pdf: 2503244 bytes, checksum: 3a51f6e015fe2ad4e18bc897b557945e (MD5)
  • description.provenance : Approved for entry into archive by Patricia Black(patricia.black@oregonstate.edu) on 2013-11-08T17:06:03Z (GMT) No. of bitstreams: 1 LaddDanielM1976.pdf: 2503244 bytes, checksum: 3a51f6e015fe2ad4e18bc897b557945e (MD5)
  • description.provenance : Made available in DSpace on 2013-11-08T21:45:02Z (GMT). No. of bitstreams: 1 LaddDanielM1976.pdf: 2503244 bytes, checksum: 3a51f6e015fe2ad4e18bc897b557945e (MD5) Previous issue date: 1975-08-15
  • description.provenance : Approved for entry into archive by Kirsten Clark(kcscannerosu@gmail.com) on 2013-11-08T21:45:02Z (GMT) No. of bitstreams: 1 LaddDanielM1976.pdf: 2503244 bytes, checksum: 3a51f6e015fe2ad4e18bc897b557945e (MD5)

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