Is a 17x13.25 prop roughly equivalent to a 19x13

8

88HP

Cadet
Joined
Nov 2, 2008
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10
I have a 17 ft. runabout with a 1988 Johnson 88hp. The 17x13.25 prop that is currently on the boat seems about right in that I get about 5000 rpm WOT with four adults in the boat. I have another prop that came with the boat as a spare (which needs repair) that is a 19x13. Would this prop give similar rpm? On one hand it is steeper pitch but I expect the smaller diameter to offset the pitch to some extent. If the rpm won?t be in the right range I?d rather just buy another 17x13.25 and trash the 19x13. Thanks.
 
Boss Hawg

Boss Hawg

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Apr 9, 2009
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Re: Is a 17x13.25 prop roughly equivalent to a 19x13

88HP said:
I have a 17 ft. runabout with a 1988 Johnson 88hp. The 17x13.25 prop that is currently on the boat seems about right in that I get about 5000 rpm WOT with four adults in the boat. I have another prop that came with the boat as a spare (which needs repair) that is a 19x13. Would this prop give similar rpm? On one hand it is steeper pitch but I expect the smaller diameter to offset the pitch to some extent. If the rpm won?t be in the right range I?d rather just buy another 17x13.25 and trash the 19x13. Thanks.
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I belive ( you can write a novel on what i don't know about props :confused:) it will lower your RPMs but dont trash it - I need it :eek:;)
 
F

F_R

Supreme Mariner
Joined
Jul 7, 2006
Messages
28,195
Re: Is a 17x13.25 prop roughly equivalent to a 19x13

88HP said:
I have a 17 ft. runabout with a 1988 Johnson 88hp. The 17x13.25 prop that is currently on the boat seems about right in that I get about 5000 rpm WOT with four adults in the boat. I have another prop that came with the boat as a spare (which needs repair) that is a 19x13. Would this prop give similar rpm? On one hand it is steeper pitch but I expect the smaller diameter to offset the pitch to some extent. If the rpm won?t be in the right range I?d rather just buy another 17x13.25 and trash the 19x13. Thanks.
Click to expand...

I couldn't make sense out of that till I realized you have the numbers backwards, don't you? It is traditional to list them as diameter x pitch. Anyhoo, you should see a lower full-throttle RPM with the 19". I wouldn't go there except in an emergency.
 
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