Tracking Fins?

[NCSUmoomba]

Can someone that is better with hydro dynamics than me explain the function of tracking fins? Also, my 2001 Outback only has two, yet the new ones have three. Why is that? I pull pretty hard on it when wakeboarding and was wondering if I can benefit from adding a third (or fourth...) fin? Any thoughts?

[Razzman]

Tracking fins are meant to help a tournament boat hold a line against lateral forces while pulling a rider. Also take into account the intended purpose of a boat dictates hull design, number of fins and placement. In 2001 the Outbacks intended purpose was skiing and slalom.

The amount of fins a particular boat has is based on hull design. I've seen many boats with only two. I've seen some late model Nautiques and Mastercrafts that only have two. In fact the Moomba XLV only has two if i remember right. I doubt you'd notice any difference, in fact you might actually make it worse.

Besides it would be a lot of glass work to accomplish as you'd have to work an area to accept it, make sure the hull inside is appropriate strengthened, and be darn sure that where you place it won't adversely affect the handling. Tracking fins aren't just placed anywhere, they are where they are for a reason.

[bjames]

The LSV has 3, so does that mean it can hanlel more lateral forces?

[Razzman]

No, it just means that hull design in that length with less surface mass works better with three. The XLV being bigger and having more surface mass probably works just fine with two is all.

[dtlaine]

My neighbors' X-15 has none. I haven't seen it on the trailer, and their lift barely gets the hull out of the water, so I can't verify it. I have no reason to think that they're not correct.

[NCSUmoomba]

Okay, sounds good. So if my boat is getting pulled sideways a bit when a heavy rider is cutting out hard, can I do anything about this? Do the fins help at all when the rider is edging out hard and the boat rolls over to the side? I assume that is what a keel is for on a sailboat, so do the fins on our boats act as mini keels or are they too smal to make much difference?

[Razzman]

NSCU, there's nothing you can do about it. Like i said earlier that particular hull was designed for skiing which doesn't see the increased lateral forces that wakeboarding produces. The fins are designed to help keep the boat tracking straight, period. Many older ski specific boats have that problem, i had one so i know. My brother in law has an older Ski Sanger that does it. Nature of the beast is all. Try keeping weight balanced in the boat, that does help a bit.

[snowboardcorey]

Tracking fins help give the boat directional stability. Ski boats in general usally have a fairly flat hull which is great for creating a wake that is symetrical on both sides, it is not good for tracking when a skier or boarder cuts against it. Tracking fins were originally designed to track straight through a slalom course, they carried over on a bunch of the wakeboard boats as a lot of wakeboard boats mimicked the flat hull design create wakes that were a very even from side to side.

The flat bottom can lead to a rough ride through choppy water so some boats like the X-15 developed a modifed V hull which uses the V of the hull for tracking ability. Typically the V flattens out a bit as you near the end of the boat, but some boats carry a good amount of V all the way through. This V provides a smoother ride in rough water.