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Old 26 May 2010, 16:05   #1
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prop sizing help

hi all im looking for some advice on prop sizing i have a 18ft bwm with a johnson v4 85 hp engine i use the boat for a bit of dohnuting and fast crusing what you recomend?
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Old 26 May 2010, 16:09   #2
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Quote:
Originally Posted by steveplumber View Post
what you recomend?
I recommend you post the following info so the prop gurus can help you:

Maximum recommended engine revs (or range)
Current maximum revs at wide open throttle (WOT)
Current maximum speed at WOT
Gear box ratio for your engine
Current prop size DIAM x PITCH, plus no of blades and Ali or S/S

If you are happy with speed / hole-shot etc?
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Old 26 May 2010, 17:53   #3
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I had a BWM Deepsea 17 with an 80 Yam and then a 90 Merc on the back and the best prop that I found was 13.75X17" alloy for general purpose with a 15" spare that I could also use if I had a heavy payload and needed some grunt.

I did a lot of experimenting with Stainless V's Alloy props and found virtually no difference in performance between the two. At the end of the day I chose the Alloy ones because they're cheaper to buy and if you hit an underwater obstruction then the prop is likely to take the impact protecting the gearbox a little.
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Old 03 June 2010, 06:00   #4
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Assuming johnson and evinrude props are the same (downhilldai please advise) I have a 15'' and a couple of 16.5'' plus a 17'' all in stainless ,one of which may be suitable.
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Old 09 June 2010, 08:30   #5
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props

Hello Bosun
are you looking to sell the props you mentioned?
If so what diameter and spline size are they please?
Cheers
RR
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