cavitation

[mr angry]

Hi, I have a 6m Zodiac RIB with a 175 Mariner V6 which cavitates like hell when turning even slightly with the engine trimed down. It has one of those adjustable pitch plastic props on it and was wondering whether to ditch this for a 3 blade metal one but here the dillema begins.
Which prop do I go for as Im not well versed at all on prop sizing.

 

[Dhadley]

Re: cavitation

If you top (straight line) rpm's are where you want them, then go with the same pitch when going to stainless. We'd have to know a bit more about your set up to offer much more than that. What's your top rpm?

 

[mr angry]

Re: cavitation

Going out tomorrow will check out wot rpm but not sure what manufacturers figure is as cant find it on tinternet.
Noticed adjustable prop set at max pitch at 18.
Does anyone have any experience of these plastic props as they seem quite flexible?

 

[mr angry]

Re: cavitation

At wot rpm reads 5500 , but I am now thinking my problem lies with the outboard having too short a leg for the boat. It was an e bay purchase a few weeks ago and seemed like a bargain but I think I will have to be looking for a longer shafted engine now:'(

 

[RCAF_FB_FHDOG]

Re: cavitation

You might consider using a 4 blade prop. It is less likely to blow-out in turns. The guys in the Mercury website just finished coaching me to a Revolution 4 prop, and I gained 12 mph on top end with better hole shot and mid-range cruising capability..

 

[walleyehed]

Re: cavitation

Measure the transom in the center from the very bottom of keel of boat up to where the engine would hang.....Then, give us the MODEL # of your engine.

 

[Texasmark]

Re: cavitation

Did you do that on Grapevine? If so, what's the water level there.

I'm fixing to trade my boat for a WWII surplus DUCK. That way I can drive down to the water to launch. :%

Nearest lake is Lavon and is in Drought stage 3 putting it between 11 and 14 ft low.

Don't want to run on it at all because at that level it's stump city.

Mark