Power boats skim the surface on planing hulls; sailboats have displacement hulls.
Once, a freighter captain said, "Going fast gets you in trouble quicker." Going fast may cost more money as well, because higher engine speeds consume fuel more quickly. Your motor's speed is only part of saving fuel money, though. The way your boat meets the resistance of the water -- when moving fast, its hull design causes it to rise and skim the surface -- affects fuel consumption, too. When you have no arrival deadline, operating your outboard at half speed will save fuel, as long as you optimize your boat's trim.
Instructions
1. Turn your GPS unit on and push your throttle handle forward to the "half-throttle" position. Take note of the boat's speed-over-ground, indicated on marine GPS receivers as "SOG."
2. Trigger the trim switch to tilt the motor down until the boat's SOG begins to drop. Slowly tilt the motor up.
3. Watch the SOG and note that the boat's speed increases as you tilt the motor up. When the speed begins to decrease, note the trim angle on the trim/tilt indicator: that's the upper limit for the best trim.
4. Tilt the motor down in small increments, noting the trim angle each time you change the tilt, until the SOG begins to drop once more: that's the lower limit for the best trim. Calculate the difference between the upper-limit trim angle and the lower-limit trim angle
5. Divide the difference between the upper and lower trim angles by two. For example, if the upper-limit trim is 16 degrees and the lower-limit trim is 14 degrees, divide the difference, 2 degrees, by 2. Add the answer, 1, to the lower-limit trim angle, 14 degrees, to determine the optimum trim angle, 15 degrees. Set your motor's trim angle at 15 degrees, using the trim switch.
Tags: trim angle, angle degrees, lower-limit trim, trim angle degrees, begins drop, best trim