I’ve found over the years that a lot of people are confused about the best way to use the trim tabs on their boats. But using them effectively can make your ride much more comfortable, as well as fuel-efficient. After all, who wants to pound going into a head sea, or get pushed around in a following sea? Or start listing in a beam sea?
The basic idea is that you want to give your boat a good attitude. It’s really a Goldilocks issue, and it changes from boat to boat. You don’t want too much bow up, and you don’t want too much bow down. So you use your trim tabs, incrementally, to find just the right spot.
The rule with trim tabs is that tabs down equal bow down (the tabs push the stern up, which means the bow goes down). In a head sea, you’ll want to trim the bow down, so you don’t pound. In a following sea, you want to raise the tabs, so they don’t get caught in the waves and push the boat around; you also don’t want the stern down low in a following sea to begin with. Deploy the tabs gradually in all these situations, so you can make adjustments along the way. In a beam sea, it’s easiest to see the effects of tabs, since it’s just a side-to-side balance issue.
Here’s a great video from Motorboat & Yachting about how to use trim tabs in a head sea. It makes it all pretty easy to understand and remember. http://www.mby.com/videos/how-to/video-head-windward
