So I’ve been experimenting with different types of fins lately. These are Four way fins.
Notice the missing box…now deep in the green Pacific.
Two questions; Anyone else have any similar experience with 4wfs? I don’t remember any major impacts, but I could have missed something. It was wobbly at first, so I probably could have saved myself from losing the box…probably not re-installable though. The cost of being lazy.
Secondly, I’m a big board denter, so the deck over the fins is usually crushed within a few weeks. I’m wondering if fin boxes with lots of surface area might actually suffer more damage than narrower, shallower options. What I’m getting at is this: is it possible I just pushed the box out with pressure from my foot? The foam is pretty whacked all around the installation, any ideas on how to do a good repair? I suppose I could Qcell the whole thing and start over.
In reference to pushing a box out, I’d have to say definitely (but it was a different system). I have the proof from several boards I made for one of our team riders. He is an excellent surfer, but he CRUSHES boards by brute force. On the first few boards I was at wits’ end trying to figure out how he was doing it because the fin and box were gone. Then I got one of the boards that was in mid-failure.
He was able to drive the deck area over the fin down to the point that the fin box was sticking out of the bottom of the board about 1/4". This particular fin system in question which goes through to the deck is very robust. It is excellent; I swear by it, but it is just this exceptional rider.
I finally found a solution by adding glass-overs. After the fin system is installed and the board sanded, I lam 18 oz of staggered patches (3x6oz) both top and bottom. There is the added hassle of sanding the area and cutting the box holes out again but the system becomes bullet-proof…
…as far as fixing, I’d jam a chunk of foam in the hole and glass it over and hotcoat it. Then I’d re-install the box. Finally, I’d do the glass-overs. Good Luck.
LeeDD, I know, I know, I was just hoping to get one more session out of it before I did the repair. As for the board being ready for the dumpster…not even close. The yellow cast is a combination of garage lighting and the acrylic sealer I use instead of a hot coat. Other than the fin problem, this board is still in pretty good shape and I love the way it surfs.
PlusOne, Three 6 oz lams per side? Wow, doesn’t that make a pronounced high spot? How big are the patches? And you’re actually laminating over the installed fin box? So you mask the box off, then xacto the opening for the fins? Hmmm. Thanks, I’ll have to try something like this if I stick with deep set fin systems.
OregonPeter, Yes it sounds brutal/overkill but for that particular rider, that’s what it took! We call him the Hulk and it is an earned nickname. In his shapes I try to anticipate the rise in cloth by using sanding screen. When done carefully, there should be no high spot, not even when looking for a reflection of one.
These layups are done on the sanded hotcoat and I no longer use any tape to protect any of the installed hardware (I used to sprinkle baby powder into the box holes to take up the drips). I’ve gotten to the point where I just have a super careful approach and they come out just fine. This concept of finbox capture is borrowed from the sailboard industry.
The size of the largest outer layer is about 1" out past the edge of the fin box. The hotcoat extends about 2" to allow for some fairing. On a retro fit, I would hotcoat out about 3", sand the outer perimeter of the patch until its’ weave shows to blend the patches with the boards’ surface. I would just barely sand the area where the box actually it however. I might even re-hotcoat to get rid of any weave showing. Then I use a Dremel tool to open the holes back up and to taper any holes that need to come out the deck for safety.
Lee mentioned duck dives and I just had a customer come in last week with that exact problem. His knee was driving the finbox out of the bottom of his board. His knee strikes the deck. The rider has not been able to consciously stop the behavior so we are going to try some patchwork with the lamination.
I’d mask around the damage and reinstall new plug with resin/chopped fiber mix. Have the fin in the plug and mask around the base so you can eyeball the toe and cant before taping it rail to rail across the top of the fin as resin sets. Grind away any excess and do as LeeDD suggests… glass over the seam where the edge of the plug meets the board. Yes, mask the fin slot and cut away with razor blade or x-acto after gelled.
When installed according to directions, most of the plug sets should have patches on the deck above the plugs and around the plugs on the bottom. It’s an easy cost saver and weight saver to skip those steps and plenty of guys don’t bother. Then they blame the plug manufacturers.
