Flying Scot Centerboard Repair

If you own a boat somewhere along the way you will have to do some epoxy and fiber glass work. It is not hard but it does require some planning and patience. For a while I had known that the centerboard in my Flying Scot was a mess. It got to the point that I did not even sweat it when I heard it banging on rocks. Last fall I decided that it was time to make the necessary repairs on the board during the winter. In the following text I describe what it takes to repair the end of a Flying Scot centerboard but these techniques can be used for almost any small repair. This repair is probably one of the tougher ones I have ever had to do because it required some shaping. Flat surfaces are a lot easer to fix because you can just lay down glass, sand it out, and that is pretty much it. This repair does require some basic tools, supplies, and a bit of skill. If you do not feel confident with any of the following procedures contact a professional.

The following is a general list of supplies:

  • West Systems 105 Epoxy
  • West Systems 407 Low-Density Filler
  • West Systems 205 Fast Hardener
  • Fiber Glass Fabric
  • Card Board

You will also need the following tools

  • Scissors
  • Carpenters Knife
  • Foam Paint Brushes 1”
  • Rubber Gloves
  • Mixing Sticks
  • Plastic Spreader
  • Mixing container
  • Mixing Sticks
  • Flat File
  • Sand Paper
  • Grinder (optional)

The first thing to do is pull the board out of the boat. The Flying Scot has an extremely heavy centerboard weighing almost 100 pounds so be very careful handling it. For most cases the boat has to be in the water to get the centerboard in and out. So with the boat in the water put the centerboard down to release the tension on the winch cable. Release the winch cable by unscrewing the shackle that holds the end of the winch cable to the keel in front of the centerboard. Do not remove the bolt that holds the rollers and pulley on the centerboard. If you do you will most likely lose your centerboard. Use a strong piece of rope to make a loop through the centerboard pulley. Connect the Main halyard onto it the loop. Using the main halyard winch lift the center board out of the centerboard well. You might need an extra set of hands to help guide the board as it comes out.

When you get the board home put it on a large flat work space. Make sure that it will not fall because it could severely injure you or anything around it on its way down. Spend some time and think carefully about how to do the repair correctly. My centerboard was damaged to the point that the lead in the tip was exposed and even a little bent out of shape. The Flying Scot has a weighted centerboard but other boats may be made from other materials like wood or foam. I gently tapped the lead back into shape with an auto-body hammer and dolly. I like the auto body hammer because it is light but any old hammer will do. When hitting the lead very gentle because the lead is very soft and does not need much coaxing. You do not need to put your back into bending it back.

Before mixing any epoxy I thought about how the lay up would go and where epoxy and glass would be applied. When I looked at the board I was having a hard time figuring how I was going to apply the epoxy and fiber glass. There was very little surface area to apply epoxy making the repair weaker than I wanted. To make a repair like this you need as much surface are as possible for the epoxy to bond to. I decided that the best thing to do was cut back the fiberglass to expose more of the lead. I used a utility knife to score the gel coat and an old worn out chisel to carefully remove the fiberglass down to the lead.

I also peeled off about an extra half inch of gel coat and some layers of glass, about half way down to the lead, to have a large flat area. I figured that the peeling away some extra glass would allow for more surface area that the epoxy could bond too. Removing away some layers of glass would also provide a less severe transition between the new and old fiberglass making the new glass easier to blend into the old during sanding.

I also needed to find out what the correct shape and profile of the centerboard was. I spoke with Harry Carpenter, the builder, to get the details about what it should look like. I was hoping that he would say that I just need to slap a layer of glass on it and that would be enough. However, he said that the leading edge and trailing edge had the same profile and shape. At that point I knew that I needed to put a lot of material back on the tip board. He gave me some ideas about how to make the repair that were very helpful.

Harry told me that one thing I should do is glue the tip back together.

The outer shell of the board can easily become a place where water can seep into around the lead and weaken the two halves. I wanted to put as much epoxy between the fiberglass and lead as possible so I decided to separate the outer shell of the board from the lead by gently placing two old flathead screwdrivers between the lead and fiberglass. Anything wedge shaped will work just as long as you can pull it out. Do not use a hammer to drive the wedges deep under the glass. The goal is to create enough space to be able to get epoxy in the cavity… …not split the board in half. You should be able to create a gap large enough working the wedges by hand. An eight of an inch is all that you need.

It is time to start mixing epoxy. There are several different manufacturers of epoxy. My personal preference for this type of job is West System epoxy. It is durable and very easy to work with. It seems to be very popular for marine repairs. Stick with epoxy and avoid polyester resins which can be very noxious and extremely flammable. Most importantly do not use auto body polyester resins like Bondo. Only use marine grade epoxy or, if you insist, polyester resin. Be careful using any epoxy or polyester resins, read the labels carefully and follow the directions. The chemical reaction for both materials can cause extreme heat and cause a fire.

For gluing the sides together I used West 205 Hardener and 105 Epoxy. I mixed it up and put it in a syringe to squirt epoxy between the outer shell of the centerboard and the lead. I shot in as much epoxy as possible. Then I took a large piece of wax paper and wrapped it over the end of the board. I clamped the tip of the board together using two blocks of wood to apply pressure more evenly. The wax paper keeps the wood and clamp from sticking to the epoxy. Then I waited for it to cure overnight.

Harry said that since the center board is the same profile on the front and trailing edges to use a piece of stiff cardboard to support the glass as it was built up. I decided that to trace out the trailing edge onto the cardboard that I would use as a gauge when rebuilding the centerboard profile. I took the cardboard and clamped it onto the leading edge with wax paper over it so that the epoxy would not stick to it. Through the wax paper I could also see the traced profile that I needed to build up to drawn on the cardboard.

I cut up 1 inch square pieces of fiberglass to build up the tip. Looking back I could have used longer strips which probably would have been stronger but this will also work fine for now. I mixed up a batch of 205 Hardener and 105 epoxy and wet out the centerboard using a foam brush.

You do not need to ladle the epoxy onto the area you want to build up. Just get it wet. Put the fiberglass in the epoxy and work the glass into the epoxy. The glass should be wet but epoxy should not be dripping all over. Keep applying glass and adding epoxy as needed until you go a bit beyond the profile and shape drawn on the cardboard. You will need to do some sanding later to get the shape. The next day the epoxy should be rock hard. Be careful touching it thought because it can be very sharp.

After removing the cardboard and turning the board over I was able to get a better look at the other side of the repair. A puddle of epoxy had formed between the lead and cardboard. I carefully removed the excess epoxy with a grinder being careful not to grind into the lead creating harmful dust. A file or Dremel tool of some sort could have also worked here. I also cut off all of the loose pieces of glass close to the profile of the board to clean it up a bit

After cleaning up the epoxy and loose glass I laid down fiberglass and epoxy in much the same way I did on the other side but without the cardboard support. This time I also created long strips that went over the front of the board and along the repair seam for more strength. Then I let it cure over night.

Now it was time to shape the patch to match the profile and shape of the centerboard. Using the grinder I was able to quickly (Maybe a bit too quickly) remove material. While grinding I exposed air bubbles that I knew that I had to fill in. Using West Systems 407 Low Density Filler I thickened a batch of epoxy and applied it to the surface of the repair covering all the small air bubbles and other imperfections. The filler also provides a nice layer of epoxy that would protect the glass matte underneath from being directly exposed to the elements. Once the epoxy cured I was able to finish out the board with a file and sandpaper.