Trim level for max speed

[Bigmuz7]

Originally Posted by TNDB

I think you are right in what you are saying, but because I had exactly the same boat/engine package then I guess the engine would sit at the same height on his boat as mine hole for hole ?
The top hole did put the cavitation plate right level with the bottom of the V

Depends on the hull form is the answer. Mine has a semi rounded bottom and not a deep vee at the stern, and my cav plate is a good 3 inches above the base of the hull, and its the correct setting for this hull/engine config, I've had engines that were too low before and the difference in correcting their height is amazing

[bigal]

About an hour ago, I was out at sea explaining exactly what has been described above. The sea was flat calm, we are in the middle of a heat-wave, and we were trying the various tilt angles wrt speed.
I have a 17foot BWA RIB fitted with a 70HP 2-stroke (1995), fitted with standard prop. We were doing 35 knots at 5500revs, and by tilting up we were doing just under 39 knots, but as explained, the boat is very 'nervous' so please be careful in that situation...
regards to all, ALAN- GOZO, MALTA.

[9D280]

Chris,

Thanks for that enlightenment. Facilities like that don't seem to appear on 15 year old engines at the small end of the scale - if I wanted to raise mine up the transom I'd have to go fetch my drill........ Now the conversation makes a LOT more sense!

You learn something new every day - having done so I can now go back to sleep.......