After hitting a few logs while sailing and frustrated with blowing through the bottom of slot boxes, and the lack of unavailability, I decided to upgrade my Starboard Kode Wave Twin board to US boxes.

This repair took me way to long, mostly because of the colder winter than usual and not wanting to keep my shop heated on the cold days. Here’s the basics of what I did, I’m by no means a pro, but I’ve repaired a few boards for myself, and at windsurfing centers as an instructor.

Step 1: Measuring and Removing the old slot boxes.

First thing I did was take some measurements, so I could line up the fins later, and can’t forget to measure cant, 0 degrees.

Measuring the slot boxes on a starboard kode
Measuring the slot boxes on a starboard kode

The I sanded the paint and glass just until I could see the edge of the slot boxes. Fiberglass, ohh soo itchy!

Slot box sanded down in Starboard Kode
The box sanded down to find the edge. You can also see where the fin punched through the bottom of the box.

Then I used a little oscillating tool to cut in as close to the slot boxes as I could. After I was down the dept of the slot boxes, a little encouragement with a hammer and flat head screw driver to pry them out.

Starboard Kode with slot box removed.
The slot box popped out of the board.

Step 2: Gluing up the boxes

First I had to shorten the US boxes, I felt I didn’t need the full range, I removed 30cm, from the front of each box and glued them back together with jb weld. Next each box I glued into divinycell with a mix of epoxy and microballoons, mixed to the consistency of peanut butter. A note here, I would maybe put old fins in the boxes, as clamping them crushed them a bit, and I had to sand like crazy for the new fins to fit.

US box shortened to replace slot box
The shortened US fin box vs the original

Sorry I don’t have a picture of the box glued into the divinycell, I used 1/4″ on all 5 sides.

Step 3: Cleaning up the boxes

Multiple passes with the router cleaned up the box nicely. Was very careful on the first pass to follow my markings as close as possible, then the glass worked as a template to cut the full depth. After I tested fitted the boxes, and sanded the boxes so they would fit tightly and evenly.

The slot for the fin box routed out.
The slot for the fin box routed out.

Step 4: Gluing the boxes in

There was some debate over whether to just glue the box in, or wrap it in glass. From the factory it had a layer of glass around the a foam. In the end I opted not to use a layer of glass, so let see how long it lasts. I mixed up a big batch of epoxy and thickened it with micro balloons to a peanut butter consistency. I spread the mix liberally around the inside of the opening in the board, and then on the boxes. It took some force to fit the boxes in, which was a tight fit.

The fin boxes glued in.
The fin boxes glued in.

After the glue set, I sanded the boxes down flush and the surrounding area to get ready for glass. The result pictured above. I also filled in the old US center slot, because I never run the board as single fin.

Step 5: Glassing

I glassed the fins in with two layers of 4oz E-glass. Two small patches over each fin box, and one large patch over the tail.

New fin boxes glassed in
New fin boxes glassed in, and cut out

After the glass set, I sanded down the edges, applied a filler coat, and more sanding to get a sexy smooth finish.

Step 6: Paint

A layer of sandable auto primer, followed by black and white to match the original finish.


All done and ready to shred! Lets hope it’s windy soon.