Originally Posted by memo
I've been reading the previous posts about the engine height and the element of cavitation. I've been running without cavitation with an alu prop for almost 6 months now and recently i've added doelfins to my setup. What i've read is, they say doelfins reduce cavitation.
so do you think i can increase my engine by one hole? and does the engine height effects the trim response? (I put hydrofoils mainly to drop down the bow in bad weather and so far it is successful.)
Thanks for your help,
Doel fins are good for planning faster and staying on plane with less throttle engine rpm compared to standard engines, the up-down bow issue is a matter of trim angle. Doel fins will keep you in that running position unless you change the trim angle. A hole position near the transom will make the bow go down, the farther away will rise the bow. The best is a 90% angle between engine and boat's bottom, seek a hole trim position to match angle, distribute passengers accordingly to the middle/front to balance better the boat. Doel fin might help on cavitaion issues specially on choppy waters. Other important performance factor issue is the engine height of the anticav plate to the boats bottom, a theme treated previously on the forums and recommended by engine manufacturers.
Don't confuse engine height transom/boat's bottom issues with trim angle issues. Trim angle will definitely change boats response cruise behaviour once on plane.