Learned something new about trim tabs...

[Broken Glass]

Originally Posted by Dave R

I learned a new new technique for smoothing the ride on rough water last year and have been experimenting with it this year with excellent results. Until recently, I only used my trim tabs to reduce my time to plane, lower my planing speed, and level the boat, which they excel at. I also discovered that that do a phenomenal job of smoothing out the ride at speed.

In the past when I was approaching an oncoming wake that was big enough to cause discomfort, I'd throttle back, ride over the wake at 10-15 MPH below my cruising speed, then throttle up to get back to my cruising speed. It was effective but wasted fuel. Now I just leave the throttle alone and put both tabs way down before I hit the wake. This lifts the stern and forces the bow down rather hard which makes it slice through the wake smoothly rather than ride over it. I only lose 2-3 MPH when the tabs are down, but the ride is remarkably smooth.

If it's choppy, I just leave them down and have found that I can often make the ride even smoother by throttling up, which seems counter-intuitive, but really works. My fuel consumption in MPG is substantially lower at 35 MPH than it is at 20 MPH, so not only do I make better time and enjoy a smoother ride, I save money too.

If you have trim tabs, try this technique out. If you have a planing-hull boat, but don't have trim tabs, put them on near or at the top of your wish list if you plan to spend any time on Winnipesaukee. They are worth every cent

When I am approaching a large wake, or if I am riding across and into a chop, I trim the boat OUT of level, and position the bottom of the boat so that it takes the wake or chop evenly across the shape of the bottom of the boat. ("present your bottom") This procedure prevents the hard contact with just one side of your boat bottom which is essentially slamming the flat side of your hull against the rough water. After crossing the wake, or changing the course direction, the out of trim attitude is no longer needed and I return the boat to a level running attitude.
I also installed auto trim tab controls. This makes returning to a level efficient running attitude as simple as pushing a button!

[persistence]

Just be careful not to bow steer. If in a following sea and the tabs are set with bow down to far, the bow can bury into the back of the next wave and 'steer'. You can lose control that way. It can get scary fast.

[Dave R]

Originally Posted by persistence

Just be careful not to bow steer. If in a following sea and the tabs are set with bow down to far, the bow can bury into the back of the next wave and 'steer'. You can lose control that way. It can get scary fast.

The ride is typically smooth enough in following seas that I don't need to bother with tabs and if it's bad enough for bow steer to be an issue, I'm usually going slow enough to surf. Also, my hull has laminar flow disruptors that seem to do a great job of preventing bow steer. They make a really cool noise when they are working too... You can see them in this picture of a boat that's like mine: