Been here lurking for years and making several boards, greetings to all the old school people who post here on a regular basis and share the stoke of surfing and making boards for it.
Recently shaped a few boards, and one ot these is a light 8’ kinda longboard. 20" x 2 1/2 or so.
I have seen that on many longboards, Sunova for example, 3 regular fins are placed instead of a big center and side small fins. It seem that they are located more forward than usual, by looking at the photos and comparing with the table of fin placement I use as a guide.
Mckee guide for shortboards and guns says for 8 feet board:
Center fin at 3" 13/16 (16.3 cm)
Side fins at 13" 3/8 (9.7 cm)
I know fin placement still depends on rocker curve and tail area, my board is fairly flat, not much rocker, tail widht at 12" is 14".
I am using E4 FCS compatible fins, have these enough area to fit this board?
Thanks for you advice, any help would be appreciated.
Just go with 13" and 3". With a 14" tail width you’ll be in the ballpark. You can get a bit of extra control by placing the side fins a little closer to the rail than normal… like trailing edges 1" inboard from rail and with a bit less toe-in. It kind of depends on what size waves you expect to ride and what kind of performance you are looking for.
If anything, you are more likely to run in to trouble pushing the board in to the upper wave size ranges. With that in mind, a larger center fin to fit the FCS plugs might be an option for you(?) The FCS website lists single replacement fins as being available. I don’t know what size your current fins are based on your post so you’re on your own there.
I’ve always been an advocate of the standard Bahne/FU type of center box plus side bites for a good all around one-board quiver. With a couple of different center fins moved around in the box you can really cover some size range.
4.5" center and 14" sides. John gives great advice. Put a 7" center box for lots of fin choices and extreme adjustability. A long board to me has a rounder nose. A picture would help.
Thank you, a few photos of the hotcoated board and the fins
They are placed at 13 and 3" in the picture, but seems to me a little backwards, maybe i will go with 4 and 14, wish i could test the difference. Sunova longboard, the picture of the first comment of this post, looks like its placed more forward, like 6" or more the center fin. Bert Burger could tell us more about that, read a lot from him, good fin knowledge. Also Bill Thrailkill, a lot of wisdom in this area, as important as the board itself. Really enjoy posts from them and lot of more.
Hi -
Another option might be to place a row of FCS plugs in the center line to allow shifting of the center fin from one set to another. That would be assuming that you’re using individual plugs and not the Fusion or FCS II type.
FCS plug installations are much stronger when the outer perimeter of the circle is extended to the deck so a column of resin can attach there. Relying solely on the foam and the hull lamination will not last very long. I liked to put an extra Oval patch of cloth on the deck where the circles met the deck from below. I broke many an FCS fin but never a plug. I also avoided using pigment when setting the plugs.
The original fcs installation kit had a hand tool for gouging out the foam below the drilled hole until it met the deck. Many installers skipped this step as the rings on the deck were fugly, or just an extra step, or added weight, or all of the above, and they did not care about strength.
If Using epoxy consider its exotherm when setting the plugs, use a slower epoxy or cool it, or do it in a few stages
Yes, i extend that column and the inside of the column all under the plug to the deck and fill with pure resin, not much weight in exchange of bombproof plugs.
This board is high density foam, and the plugs i use are oversized and epoxy compatible
If you really want to do some fine tuning, collect some fiberglass scraps, lay up some fin panels and position your tabs fore/aft for minor position changes. There are lots of ‘how-to’ threads on fin building around here someplace.
One thing you can do when you install fin boxes, especially those FCS plugs is to use fiberglass cloth scraps to make a slurry. I cut the left over glass from laminating boards into pieces large enough to make fins. I cut the sections that go along the rail that are narrow into small chopped up pieces, about 1/8" in length. Just take scissors and cut the glass up. Then I add that chopped glass to the resin to fill the void where the holes meet the deck. Use a small stick or toothpick to push it down. The glass slurry will be much stronger than just using resin, or resin with micro-balloon filler.
I use to make an entire patch of wetted fiberglass around the plug, press home and fill with resin, but others prefer milled fiber or similar. Somewhere I read that filling only with resin without fiberglass is more resistant, maybe because of the elastic nature of epoxy without hardening with the reinforcement. Never did test panels or similar but never broke a plug, leash or fin installed this way. By the way I dont like very much removable fin systems, like the feeling of a one piece board.
FCS makes an adapter that fits either the 10 1/2" or 7" longboard box… The adapter allows you to use a standard FCS two tab fin in your longboard center box. These measurements that are getting thrown out are all over the map. I set a standard/normal thruster at 3 or 3 1/2" center and 11 or 11 1/2" side. I tow in at 1/8 or 1/4" depending on the length of the board. I set longboard 10 1/2" center boxes at 4,5, 5 1/2. Or six inches. Depending on length and type of board. Performance long board or Classic. My side bites are generally at 16, 16 1/2" or 17" based on type of board and the wave to be ridden. Lowel
