20" or 25" shaft lenght for my 4,7m Searider?

[dodl]

Hello,

A very competent forum, you have here! Found it today, and there are even some Avon Searider owners...great.

I own a Avon SR470 and think there is a problem with the outboard shaft lenght. I mounted a "long-shaft" '76 Mercury 500 with 20" shaft. But it seems i can't get the anti-cavitation plate down enough. All i can get is about 2" above the keel. Mercury recommends anti-cavitation plate and keel at the same height. I also get some water into the boat from behind when planing. I cannot mount the motor down any more.

Is it possible i need a 25"?? I could not believe that. Do i have just a bad boat-outboard combination? Or is it normal with the searider to have the motor that high on the transom?

many thanks
martin

[Pete7]

Martin, can't believe you need an extra long shaft engine on a 4.7m Avon. Measure your transom, it should be 20" - 21" in height. Have you got a short shaft engine by chance ?

Pete

[dodl]

Hello Pete,

It is definitely a long shaft. I will measure the transom on monday. Next week my digital camera should arrive, so i will make a photo too.

I also could not believe that i need a 25" on a RIB of this size
On the other side, to me it seems impossible to get the Mercury down any further.

thanks
martin