Posts: 3480
Location: Elk River, Minnesota | Hi esox and company,
Trimming is a constantly changing thing...it all depends on what you are doing with the boat, the conditions you are faced with, and the weight distribution of the boat as well.
When trimming, the most efficient position is found when the boat either starts to porpoise, or you continue to trim up and you start to lose speed and RPM's jump. The latter is definitely one you will notice...especially if you put the boat into a slight turn.
Also of note, if you are not trimming up while on plane, you have a huge amount of "wetted" surface which, with more boat in the water eats speed...and boat efficiency. And...as guest said, if you keep it trimmed down while at speed, there can be as much as 1000 RPM difference from optimum trim angle. As an example, my rig (tin with a 90hp yamaha) would run at 4500 trimmed down when calm, but would turn 5350 while trimmed to optimum. So...lots of room to go if you are trimmed down. If you were trimmed down, I would guess you might have found the steering to be a little stiffer? I would assume you have hydraulic, and having not run a hydraulic steering, I'm guessing there....definitely not sure on that one. I would bet, though that if you turned it would turn on a dime if you cranked the wheel hard enough and that front end would whip around. THAT is a good thing... But...not so good if you are running a straight line.
Trim is constantly changing...when cornering, trimming down allows the bow to help carve the turn. When straight, optimum trim is getting the bow to begin to porpoise, then back down just a touch to settle the bow. Once there, it will need to continually be adjusted for the conditions...more waves and into the wind, trim down accordingly to smooth out the ride. Much of what you do with trim is a "feel" thing...get it to what you are most comfortable with and continue to adjust as conditions do to stay with your comfort zone.
A good way to see the use of trim is to watch some of small outboard racing...not the drag racing, rather the course racing... When they do the helicopter thing along side the boat, and the boat goes into a turn, you can see them trim down, then on the straight, you can see the bow come right up/
Boy...just thinking about all this has got me antsy...I'd love to get in that boat and take a ride!! It's a sweet looking rig and to be honest, I bet it makes an awesome fishing platform.
Steve
Edited by VMS 12/18/2008 9:53 PM
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