Deep Turn Stainless Fin . . .
Topic: Many types have been made over the years (incl. the x-wing looking one).
Here's one that WBBrian and I came up with. I did a run of 10 - and after they were all done, Brian suggested that the next batch be made a little wider. The idea is to get them to be wide enough that they line-up with the edge of the center section of the ski. Mine lined-up with the ski I measured them for, but were a bit narrow for his custom skis.
They are a great replacement for a stocker though - and I think they add a tiny amount of strength too.
What Do THey Look Like?
Here's a few pics . . .
How Do You Mount Them?
When using a stock ski, you need to either cut the vertical fins off of a stock skeg - or - make a spacer plate to fill-in the cavity left from the stock skeg.
Then position the new skeg properly and drill the holes. NOTE: Do not push really hard when completing the hole - that way you won't have a nasty exit hole on the top of the ski. Push too hard and the hole will look like an old broom.
When mounting, I use a liberal amount of 5200 to seal all of the way around the skeg.
I also use what's called "sidewalk bolts" to mount the ski (http://www.mcmaster.com/#sidewalk-bolts/=eg1ztri). They're low profile and very strong. I use stainless washers and a nylok nut on top - with the length just long enough to make it through the nylon. If the threads stick up a tad - I put on bit of the "liquid electrical tape" so that the rider won't get poked.
One last thing to consider - do you take the time to "round" all of the leading edges of the fin? Well, I do cleanup the leading edges of the vertical fin, but don't really bother with the edge that sits flush with the ski to much. Why? Well, it's running in what I call "dirty water" so it wouldn't help much. That means, it's behind the scoop running in the "soup" so it really wouldn't help much to smooth out that edge.
If we were running over 80mph, then I'd have all of the edges perfectly square. Have you ever seen the skeg on a hydroplane? Square edge. Why? To create a "cavitating" effect and reduce drag.