How about the automatic trim tabs controller sold by bennett? Is this a
reasonable option or can they be dangerous should they fail at the wrong time?
There is no doubt that the trim tabs drag, but they can reduce the amont of
drag that the hull creates and this will often be the dominant factor.

On many boats the trim tabs are essential for getting on plane. After
that, the trim tabs can be adjusted to provide the best ride and/or speed
(which usually is an indication of reduced drag and increased efficiency).

If you over extend the trim tabs you will force the bow down into the water
and increase the drag. If you retract the trim tabs, many boats will go
into a bow up position, which also increases drag. It isn't necessary to
understand which forces are acting against each other, just watch the
speedometer as you adjust the trim tabs.

Rod McInnis