The Most Dangerous Trim Tabs in the World? Our Experience with Humphree on Performance Boats

At YachtWay, we don’t just list yachts—we test them, push them, and uncover what works and what doesn’t. And when something doesn’t, we say it. Especially when safety is on the line.

One of the most alarming experiences we've ever had at sea came courtesy of a system that’s supposed to make your ride smoother: Humphree trim tabs.

Let’s be clear: Humphree has made a name for itself in the world of cruiser stabilization. Their automated fins and trim systems are common on many boats—and in that category, they seem to do the job. But as the company attempts to expand into high-performance territory, things start to go sideways. Literally.

A Simple System—Until It Isn’t

The setup is typical: one trim tab on either side of the transom, controlled via a dedicated panel or integrated into Garmin MFDs. On paper, it’s a smart system—automatically adjusting to level the boat at speed.

But when you're running at 50+ mph, “smart” better mean bulletproof. What we experienced was anything but.

Out of nowhere, the boat violently leaned starboard as one of the tabs deployed mid-run. The helm yanked sideways. Cavitation exploded beneath us. Passengers behind were nearly airborne, grabbing anything they could as drinks, phones, and gear were flung across the deck.

If we hadn’t been locked onto the wheel, someone could’ve gone overboard.
We immediately reached out to Humphree. Their response? A software bug—just update the system. Fine. We did.

Same result. This time it slammed port.

We Tried Everything to Shut It Down

So we did what any experienced team would: turned off the system. Then disabled auto-mode. Still happened.

We killed power at the breaker panel. No electricity. No user input. Finally—some peace. The boat drove perfectly. Until…

Boom. Trim tab slams down. Boat jerks port like it caught a rogue wave. 

No power. No commands. It just… moved.

At that point, we literally dove into the water, checked the tabs ourselves—fully retracted. Got back in, shut down the boat completely, took off again, and it happened again.

You can’t make this up.

Our Take

We’ve tested boats at every speed, in every condition, all over the world. And this is one of the most unpredictable, uncontrollable, and frankly dangerous behaviors we’ve ever seen from an onboard system.

Unless something radically changes, we do not recommend Humphree trim tabs for performance boats.

If you’re cruising at 20 knots? Maybe it’s a different story.

But when lives are on the line at 70 mph? There’s no margin for “maybe.”

We’ll gladly update this article if Humphree addresses the issue and we can verify real-world stability. Until then, our advice is simple:

Don’t install them. Don’t run them. Not on a fast boat.

Safety first. Always.