How to Use Trim on a Boat to Improve Performance
One little control on your boat can offer all kinds of benefits: higher speeds, a smoother ride, and better fuel economy. That control is called the trim, and there are ways to manipulate it to improve your boat rides.
All it takes is knowing how to correctly use your boat’s trim to help it run its best in the water. Here are some tips on how to use trim to improve comfort and speed on a boat.
How to Increase Speed on a Boat with the Trim
If you feel like you’re not getting everything you can out of your boat, it may simply be a matter of friction between the bottom of your boat and the water. The easiest way to beat this problem is to get more of the surface area of the bottom of the boat up out of the water.
Start from a dead stop with the trim all the way down. Once you get up to top speed, press the “up” side of your boat’s trim switch for a half-second at a time. You’ll notice the speed pick up, and you'll feel the sensation of riding higher above the water. As you continue to add up-trim, you’ll eventually see the bow of the boat start to drop, and then rise again. It’s a phenomenon known as “porpoising.”
It tells you that you’ve stepped just past the line of the maximum trim you can use to get speed out of your boat. What happens is the bow up pressure you’ve added through the trim switch is no longer enough to lift the bow any higher off the water. Simply hit the “down” side of the trim switch for about a second and the porpoising should stop. At this point, the hull of your boat will glide efficiently over the water.
How to Get a Smoother Ride Using Your Boat’s Trim Switch
When the water is glassy, the boat will almost always run smoothly. But all it takes is a little chop to make the ride bumpy. Shorter boats are more susceptible to bumpy rides, so the smaller your boat, the more important it is to use trim to even out the ride.
To begin with, there’s an important relationship between speed and chop. Slowing down helps mitigate a bumpy ride, but speeding up can also beat the bumps by getting the hull up out of the water. Adding some “up” trim to a slightly lower speed can also help smooth out your ride. But if it doesn’t, try going the other way with the trim. It often takes some experimenting to get the right balance between throttle and trim for the most comfortable ride.
How to Increase Fuel Economy with a Trim Adjustment
Friction is the key to the relationship between a boat’s fuel economy and trim. The point of adding up trim is to decrease the amount of the boat’s hull in contact with the water.
This in turn reduces friction, and that allows your engine to work a little less to maintain a given RPM or speed. Just as you would to get the best speed out of your boat, add trim “up” a little at a time until you reach the tipping point where the bow of the boat stops rising and starts porpoising. Then, simply back off a little by pressing down on the trim.
In every case, what you’re doing with the trim is decreasing the interaction between the hull and the water. This can offer a faster, smoother, more efficient ride.