On Mon, 22 Nov 2004 13:13:13 GMT, "Eisboch"
wrote:
Many boats that are
under or marginally powered benefit from lowering the tabs to help get on
plane, but it is a balance of lifting the stern and generating more drag.

I went through this exercise with my previous boat (Bertram 33
sportfish). With a full load of fuel and a lot of gear on board it
was difficult to get the bow down to the correct attitude. The boat
was planing but cruising speed was a knot or two short of what it
should have been and the boat didn't feel quite right. The folks at
Bennet tabs were helpful in recommending the correct size:

http://www.bennetttrimtabs.com/

If the OP's boat is underpowered, my guess would be that larger tabs might
help lift the stern to get on plane which will the significantly reduce
overall hull drag. Once on plane, he should slowly raise the tabs back up,
while watching his tach until he finds the "sweet spot" of max RPM for a
fixed throttle setting.

That's about right. I would start by setting my throttles at correct
cruising RPMs and then adjust the tabs for best speed. That usually
causes RPMs to increase so I would then throttle back slightly and
readjust.

Whether or not a particular boat will be helped by larger tabs is
somewhat problematic. It depends on the boat, how it is powered, how
heavily it is loaded, and weight distribution.