Learned something new about trim tabs...

jeffk · 05-24-2017, 10:01 AM

In a similar vein, the trim tabs can also be used to reduce or eliminate porpoising. When the wave spacing and current running characteristics of the boat cause the bow to bounce up and down continually, using the trim tabs to force down the bow can be very effective. As noted, there is more drag from the tabs and probably pushing through the waves makes the engine work harder but I just push the RPMs up to compensate and enjoy the smoother ride. Yes, you will burn more gas. C'est la vie.

However, just thinking this through further, when the pounding caused by porpoising would cause me to drop speed to just about planning (18 MPH), it's fuel inefficient. Using the tabs allows me to get closer to the "sweet spot" of fuel efficiency around 25 - 35 MPH as the boat lifts further out of the water. The fuel cost of using the tabs may not be all that much?

05-24-2017, 10:01 AM	#3
jeffk Senior Member Join Date: Feb 2004 Location: Center Harbor Posts: 1,173 Thanks: 206 Thanked 437 Times in 253 Posts	In a similar vein, the trim tabs can also be used to reduce or eliminate porpoising. When the wave spacing and current running characteristics of the boat cause the bow to bounce up and down continually, using the trim tabs to force down the bow can be very effective. As noted, there is more drag from the tabs and probably pushing through the waves makes the engine work harder but I just push the RPMs up to compensate and enjoy the smoother ride. Yes, you will burn more gas. C'est la vie. However, just thinking this through further, when the pounding caused by porpoising would cause me to drop speed to just about planning (18 MPH), it's fuel inefficient. Using the tabs allows me to get closer to the "sweet spot" of fuel efficiency around 25 - 35 MPH as the boat lifts further out of the water. The fuel cost of using the tabs may not be all that much?