Replacement of the Centerboard Gasket

By Rolf Zeisler 7378 and Barney Harris 6701 & 8011

Why this article? Barney made me write it as the price for the loaner boat I used at the WRSC Azalea Cup. He is also the technical reviewer and co-author of this note. Anyway, a small price to pay considering the couple of rub marks 7526 has suffered and which Barney will make invisible again; and Sue and I had a good time sailing with some really great moments, until we got bitten by the foreign layout of the lines in the boats. What does this all have to do with the centerboard gasket on Cool Runnings? A lot, when the boat was not ready for the regatta.

In early April, Barney held a class at his house on boat maintenance, with the subject of demonstration and active participation being “Replacement of the Centreboard Gasket”. An easy project if you are prepared as Barney was. In fact, it all worked like in one of those cooking shows where a 2-hour preparation time is compressed into 10 minutes. That’s about the ratio I found between the demonstration and the actual performance of the tasks. Now, I hope that the reader will not be scared away from a beneficial maintenance project by the time frame. I hope that this article will help to keep control over the total project time and encourage use of “Barney’s Rule”, which requires that you spend at least 30 minutes with your boat every day as long as the project takes, even if you only stand there with a beer and think about the project for the 30 minutes.

Now to the project. It helps if you can get rid of all the stuff in your garage and reserve the space for your boat, where she will be upside down, nice and dry.


To be set, get the following materials:

  • 1 pair of gaskets (HAPCO)
  • 1 (better 2) tubes of 3M 5200 fast cure marine sealant (West Marine)
  • Sand paper (120 grade)
  • Acetone
  • Zinc-chromate spray paint
  • Epoxy filler


  • screwdrivers
  • utility knife
  • razor blade

Step 1: Removal of old gasket

Did you already take out your centerboard? Yes! Good, we continue with removing the Aluminum strips that hold the gaskets in place. This is probably an easier task with all Phillips head screws. In my case, one of the slit screw heads was damaged. I got the screw out a day later after carefully re-grooving the head with a newly-purchased Dremel tool flex shaft extension. Save the screws. Make sure that you don’t bend the metal strips, and keep track of where they came from, i.e., port/starboard & bow/aft end, since the fasteners are not necessarily positioned symmetrically.

Step 2: Clean-up

Sand the aluminum strips to the base metal. Spray paint with Zn/Cr for corrosion protection. Set aside to let dry. Remove all the grit and old sealant from the groove in the centerboard capping. Repair any cracks in the groove with epoxy filler. Clean all with acetone.

Step 3: Set the new gasket

Put a bead of marine sealant in the corner of the groove around the centerboard slot. Lay in one gasket strip with its stiffened edge flush to the outboard edge of the groove. The strip should extend a couple of inches beyond the centerboard slot on both sides. Tape it in place on the ends. Lay in the painted aluminum strip and start fastening it in the middle. Dip the screw into marine sealant and press it through its hole in the strip and the gasket material into its original hole, and tighten. From this, work your way to the front and to the back. Make sure that the gasket maintains contact with the outboard edge of the slot. Repeat this on the opposite side. When both strips are set, trim the front straight across to fit into the front of the slot. Cap with its short aluminum strip. On the aft end, use a 45 ° cut to achieve a 1 inch long V-shaped opening into the actual centerboard slot. Cap with the short strip or leave open. This all happens well within the working time of the sealant. Go away now and have a beer.

Step 4: Finishing up

Barney didn’t demo this. After all is cured, remove excess sealant with the utility knife or razor blade. I found this to be a much easier task in the areas where I took action the day before and removed most of the excess before curing. Re-insert the centerboard and be amazed how smoothly the new gasket hugs your board.

While you are doing this project, you have plenty of opportunity to look at your boat. Go by Barney’s Rule, spend some time with her and extend your maintenance plan to other needy areas or make this long-deferred adjustment to your running rigging – and do a little every day, or you might miss the next regatta!

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