Detachable Fins

Hello All. A couple years ago, I mounted a detachable fin to the stern of my kayak and it greatly improved tracking. The problem is that this thing measures 9” deep and works well at bringing back weeds and sludge, not to mention limiting shallow water paddling.

My question is this: Just how long does a fin need to be to affect the tracking of a kayak? I’m seriously thinking of trimming it down with a jig saw. Your thoughts and thanks.

Boats with retractable skegs are adjustable because the amount of skeg you need to deploy depends on the conditions. In general, the more downwind you are going, the further down you need to deploy the skeg.

The size of the skeg also varies based on how much the boat naturally tracks.

Guess I am saying that there is no one set answer.

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Correct. But this is a marine-glued mount with a detachable slide-in fin. It’s fixed to one size and one position.

You could pick up a smaller fin for use in shallower water. The ability to swap out fins for different conditions on my SUP has been very helpful. And/or you could grind the one you have into more of a so-called “weedless” shape. The trouble is that most weedless fins aren’t so weedless in my experience - they all hold onto various detritus. I can feel it when it happens since it effects my glide, and I can move to the back of my board, reach down, and scoop it off. This would be tough to do in a kayak.

If it is a surfboard fin box ( and you installed it right) there are a bunch of fins that would fit. You can even paddle it without a fin, like it was designed for.

Skegs and fins are usually for big water, where waves and tides affect everything. In flatwater it should not be necessary.

The rule of thumb for SUPs is that if you can paddle on one side for more than ten strokes, without causing a turn, the fin is too long.

I don’t have a ruler w me, but pretty sure that neither of the skegs on my primary boats deploy quite that low. 7, maybe 8 inches at most? One is boat sized for an average paddler, other is a shrimp sea kayak.

Point taken above, of course both are retractable. And virtually never get used in calmer water,

My first kayak was a whitewater crossover boat, 9 feet long with a fair amount of rocker (LiquidLogic XP9). I loved that boat, but outgrew it in skills. It was great in whitewater, but I also paddled it in flat water locally. It didn’t track at all, until I engaged the drop skeg. So I can absolutely see that if someone has a short squirrelly boat where a fin might come in handy. It’s certainly cheaper than buying a new boat.