A Simplified Method of Calculating Propeller Parameters for Small Trawlers
It is quite common to encounter a propeller installed on a trawl that does not develop adaquate thrust to pull the trawl at a specified trawling speed. The immediate actions usually taken are to reduce the size of a trawl, change to a new propeller or install a higher powered engine. All these alt...
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| Main Authors: | , |
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| Format: | Article |
| Language: | English English |
| Published: |
1984
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| Online Access: | http://psasir.upm.edu.my/id/eprint/2230/1/A_Simplified_Method_of_Calculating_Propeller.pdf http://psasir.upm.edu.my/id/eprint/2230/ |
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| Summary: | It is quite common to encounter a propeller installed on a trawl that does not develop adaquate
thrust to pull the trawl at a specified trawling speed. The immediate actions usually taken are to reduce
the size of a trawl, change to a new propeller or install a higher powered engine. All these alternatives will
impose a financial strain on the fishermen. Therefore, a simple method of calculation is being suggested
to obtain a spectrum of propeller parameters such as diameter, pitch- diameter ratio, speed, quasipropulsive
coefficient and propeller performance coefficient for a given engine model. The best combination
of parameters can be obtained in order to satisfy a specific trawling requirement. Usually the requirement
is stated in the form of thrust of propeller to overcome total gear drag at a specific trawling speed.
Total gear drag can be determined by a model test or mathematical modelling. Three engine models have
been studied and for each model values of thrusts, propeller performance coefficients and quasi- propulsive
coefficient were calculated. Having known the values of torque coefficient (J.l) and advance coefficient
(¢) the values of pitch- diameter ratios were obtained from propeller performance curve. |
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