props

[Micky]

Hi guys, can anyone explain the differance between a normal prop and a sail prop and what advantage are they, would it be better to change my mercury 8hp to a sail prop??? cheers.

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[gonfishing]

Hi
Welcome to the forum.
leave the prop as it is, there is no benefit in changing to a sail prop as the name implies it is for sail boats the blades collapse so that it creates less drag when under sail, they only open when the engine is running in gear.

Julian

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[Wiggo]

unless he's talking about a sail prop for an outboard. In which case, it's designed to give more push at low speed while sacrificing all out power - i.e. it is meant to push heavy sailboats along without overloading the motor, rather than blamming a little tender around.

<hr width=100% size=1><A target="_blank" HREF=http://homepage.ntlworld.com/graham.wignall/boats/eulimene600x800.jpg>The old and the new</A>

 

[Talbot]

A sail prop, is normally known as a hi-thrust prop. It is designed to have a much larger blade area than a normal outboard prop, although the pitch of the prop will probably be smaller - thus reducing cavitation, and also allowing outboard to develop max revs. These props are very effective on sail boats. I suspect that you will be able to change to a hi-thrust prop, but will not get all the benefits that an engine designed for it will achieve. The Yam 8 and 9.9 are the best known of the engines designed as high thrust units, and I expect that their power curve is very different from that on a normal outboard.

I fitted a high thrust prop to a 30 hp yamaha, and the biggest improvement was to astern power (massive differennce)

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[Micky]

Hi chaps, guess i should have given more details. I have got a 8hp Mercury fitted to a 21ft Vivacity sailing yacht, the engine has a standard prop. Have been told that a sail prop would be much better to use??also it would use a lot less fuel and push the boat along much quicker with less revs. Cheers

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