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Old 19 May 2008, 10:13   #1
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Stainless steel Prop Any Good

Hi
I have a 4 metre Rib with a 40 hp Yamaha engine goes fairly well 30 mph right conditions, but sometimes on take off or turning at above 10mph it loses drive in water, slow down start again and away i go, fitted trim tabs to stop bow raising too much and is now stable on the plane, but i wonder if a stainless prop would give me something more.
Ideas thoughts where from how much

Thanks Stuart
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Old 19 May 2008, 13:34   #2
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Have you got power trim?
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Old 19 May 2008, 17:12   #3
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Thanks for reply
No just manual bar setting
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Old 19 May 2008, 17:35   #4
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I have a similar set-up as you with a Yamaha 40HP, 3 cylinder, Autolube, 2-stroke engine to power a 4.2m Zodiac 7-Man Pro. Has a steering console and bench seat, and back-up 3.5 Tohatsu auxilliary.

I looked at Yamaha Performance stainless steel propellers, which would give the boat more grip from standing start, but it is difficult to justify given the likely cost (+ 300). I don't think you're going to see a dramatic difference in performance from such a relatively small engine. Possibly 3-4 knots extra at WOT.

Think the standard aluminium prop is 11 3/8 diameter x 12 pitch (G).

What I looked at was the possibility of up-rating the engine to a 50HP by replacing exhaust manifold and carbs, as effectively the 40/50HP is the same engine. Still doing my research on this though.
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Old 19 May 2008, 17:43   #5
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Since you've got the planing issue all worked out, you might want to see about a higher pitched stainless prop with cup like the Powertech REB series props. You will loose a small bit of hole shot power, but could potentially gain more speed and loose some of those caviation issues. Shoot them an email, they are very helpful
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Old 19 May 2008, 17:45   #6
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Quote:
Originally Posted by stul View Post
Hi
I have a 4 metre Rib with a 40 hp Yamaha engine goes fairly well 30 mph right conditions, but sometimes on take off or turning at above 10mph it loses drive in water, slow down start again and away i go, fitted trim tabs to stop bow raising too much and is now stable on the plane, but i wonder if a stainless prop would give me something more.
It would give you a tad more top end speed but wont stop you losing drive on cornering as thats a cavitation issue,..a trade off with your trim tabs perhaps ... unless you were serious about your knots I wouldn't bother given the cost.. plus if you hit a rock with your stainless .. your gearbox will not thank you
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Old 20 May 2008, 18:50   #7
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Thanks for all replies
Stainless prop 300 might or might not sort problems out, thinking of trying doel fins to get water around the prop a lot cheaper, any thoughts?anyone tried them?
stuart
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