Batboat Rebuild; Sanding, sanding and more sanding.

In May I began to strip the household paint off the Batboat hull to prepare it for repairs and repainting. June I started sanding only to find that the majority of the bottom and stern had sever damage to the gelcoat.

I figured that this craft sat out on the ground for a number of years allowing moisture to seep into the gelcoat and expand during the winter.

All of the really bad blistering damage to the gelcoat is consentrated in one area (outlined in yellow). Looking closer, this is mostly where white gelcoat is on top of a blue layer of gelcoat and where blue is on top of white and blue.

To fix this I had to sand the gelcoat needs to be sanded down to reveal all the blisters and cracks. This was a huge pain in the you know what and its all I did nearly all summer.

Sanding, sanding and more sanding.

Above are sanded blisters. This was an unpleasant time for me and still don't like talking about it.

One of the purposes of sanding gelcoat is also to smooth out surface imperfections. Here I could start to see the weave of the original fiberglass cloth. The white areas indicate high spots and the black is low.

When these fiberglass boats were made it started with a mold. A mold release was sprayed into it then polyester resin gelcoat was sprayed on top followed by layers of fiberglass cloth.

Polyester resin shrinks slightly as it cures revealing a slight weave pattern. It isn't visible in the final result as it leaves the factory unless one is looking for it.


This is a lot of hard work. I work out and excercise regularly, however, the odd many positions I was sanding causing a lot of severe, painful muscle cramps. There were days where I couldn't stand living in my own body. Not even stretching before and after sanding were much help.

Sanding the hull was the most miserable and painful experience I've had in recent memory.

This work continued all month into July.


I devoted all of July 4th to getting all of the latex paint sanded off. I used a flexable longboard with 60 and 80 grit sandpaper then switched over to a palm sander.

The next day the muscle soreness was so intense I spent that and the next day in bed with bottles of beer and hard liquor. Hated to do that but it was last resort. The cramping and spasms were unbearable.

These are "spider cracked" areas. It happens where the gelcoat is flexed beyond capacity. Water gets in and expands from winter freezing causing more and more delamination. The best fix is to take a grinder and remove the gelcoat down to the fiberglass and fill with epoxy or polyester filler.

The original Ocean Blue and Sand gelcoat.

Finally, finished!

Now to pop the heads off all the blisters. :(


The gelcoat was in poor shape in most of the rear half bottom of the boat.








These are at several point in the trihull bow and eventually I ground the gelcoat down to the fiberglass and filled in epoxy filler.

The work place I picked in the back yard was a spot with with no trees to dropping stuff. One thing I didn't count on was this maple tree that had developed a bad infestation of scales. The scales bugs excrete honeydew which I now discovered is airborn. My car parked over 80 feet away on the other side of the house was even coated with the sticky goo each morning. And so was the Batboat.

I found that a wipedown with mineral spirits dissolves it quickly.


The back yard.