It's possible I need another coffee, but I think the two answers from Joe
and RichG are actually incorrect. I'll try not to screw this up, but here's
what I think I know.

1/ The tab isn't for low speed use, it's for planing speeds.
2/ You move it the "wrong" way to make it do the right thing. The reason
for this is that it steers the outdrive, not the whole boat. So, if your
boat, on plane, steers to port, you want it to steer more to starboard (to
go straight), so that means the outdrive has to turn to starboard, but that
means the front of the outdrive is now aiming more to port (because you push
the stern to port to turn the boat to starboard...), so to use to the little
trim tab "rudder" to steer the outdrive that way, and because that little
"rudder" steers the "stern" of the outdrive the same as a big rudder steers
the stern of a boat, the trim tab's trailing edge is turned to port to make
the outdrive aim more towards port (which we call turning the outdrive to
starboard).

There, that wasn't so hard. A few points:

Turning the outdrive to port would be clockwise, from above. That's the
opposite of what Joe said. (Awfully sorry, and I hope I'm getting this
right.)

If your boat turns to port, turning the trim tab to port initially looks
wrong. That's because, as said, it's to turn to the outdrive, not the whole
boat.

Turning the trim tab to port is actually making it aim to starboard, but the
nomenclature of rudder usage dictates that we use the side towards which we
swing the trailing edge. (Dontcha' just love this?)

====

Charles T. Low
- remove "UN"
www.boatdocking.com/BDPhoto.html - Photo Contest
www.boatdocking.com
www.ctlow.ca/Trojan26 - my boat

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"RB" wrote in message
...
'77 Johnson 115hp.

How do I set the trim tab vane on the lower unit?
It's easy to physically loosen, set, and tighten. However, what I'm asking
is where to set it, how to know if it's the right setting, etc. I seem to
remember it's some kind of trial and error thing, but I don't know what to
look for. Please give me a quick crash course in the care and feeding of
that thingee.