2020.07.12 - The Next Major Job I
It's been a while since I did anything on Naiad and I have to confess that I have been putting off the next part. Mainly because it will involve taking apart some of the cockpit to be able to do the job properly and it does need to be done properly or I'll be doing it again next off-season. Initially it was because I was so fat that I couldn't bend down to get to the places in which the work needs to be done but since I lost a whole heap of weight, I no longer have that excuse. Recently it has been because the work is tedious. Occasionally it has been because the temperature has been too hot and the epoxy just would not be useable long enough.
Still, it has to be done and right now I'm in the mood to get it sorted out.
The task is to seal the join between the hull and the bulkhead separating the cockpit from the cabin. I should have done this whilst the cockpit was being constructed and I don't know why it didn't get done but it has proved to be troublesome and so it has to be rectified.
This is where the trouble is most obvious. The white bit on the right is the centreboard case, on the left is the side of the port cockpit locker and in front is the bulkhead to be sealed, or the port side of it. I have already scrapped off the sealant I'd used to try and stop the problem and sanded the paint back to bare wood.
The problem is that gap at the bottom, it lets water in the cockpit flow into the cabin bilge. I had tried to seal it up but I had put a coat of paint over the epoxy paint that the previous owner had applied and the paint I used did not stick to the previous coat. Very quickly the two paint layers separated and that allowed the rain water in the cockpit to leak into the cabin bilges despite the sealant.
I took off the covering piece that I'd stuck across this joint using sealant and I had to destroy the wood in order to get it off. The sealant was not going to let it go. I'll have to think a bit before replacing this part with sealant when the job is being finished up.
This is the inside of the locker and when I looked at this I decided that there was nothing for it, the whole thing had to come out. It was the only way I was going to be able to scrape the paint and other detritus off the hull to allow the epoxy to adhere properly to the wood.
This is the next bulkhead forward and this one was sealed properly so I don't need to go beyond this point. Frankly, If I get water in here then I have more to worry about than water getting into the cabin.
Where I did not glue things together I used screws and the two screws holding the locker side in place were inside the battery compartment. If you look carefully you can see a water stain on the plywood that bisects the upper screw hole. This is how far up the wood the rainwater has soaked.
I had to take out the battery, of course, but knowing that this might be necessary I made the leads long enough to do so without having to disconnect them.
And here you can see the second and more insidious problem caused by not properly sealing this joint. The water has wicked up into the plywood and if I had not done this task, the the plywood would have eventually rotted.
Now this is not cheap plywood, it is BS1088 certified Marine Ply and whilst that means that it is completely waterproof and has a set resistance to fungal attack, it does not mean that if you soak the wood in fresh water and dry it repeatedly that the wood will not eventually rot as it most certainly will.
Being certified as waterproof in this instance means is that the glue used to stick the veneers together will not dissolve in boiling water.
Back to the outside again and the side of the locker has been removed and put aside.
The bulkhead could then be taken out...
...and the side bulkhead as well. The photo was taken after I had scraped and sanded back to bare wood and cleaned up the mess.
Since this job has to be done properly, I brushed epoxy on to the bare wood and then used peel ply over the wet epoxy.
One of the disadvantages of this particular epoxy formulation is the curing process leaves an amine product on the surface of the cured epoxy known as amine blush. This is a waxy substance and once it has formed you have to remove it either by washing it off using warm water as it is water soluble, or by sanding it off. Neither of those two options is particularly attractive so I used the peel ply.
This is a glass fibre mat that is laid on the wet epoxy and then more epoxy brushed over the top. When the epoxy is cured you pull the peel off and it removes the top layer of epoxy and the amine blush with it, leaving a surface that is immediately ready to be painted or more epoxy applied.
You don't have to do this if you put more epoxy on top before the epoxy has fully cured since the amine blush is only produced in the final stages of the curing process.
For this job the epoxy will cure way too fast to avoid the amine blush, it is 20 Celsius and the pot life of the epoxy is only about 10 minutes. It would take much more time than this to reassemble the bulkhead and then to start the next epoxy stage so leaving it to cure is the only option.
A better view of the section that has been removed. I took off the cockpit locker lid as well for ease of access.
Right early on in the restoration project I had debated whether or not to use plugs over the screw heads and decided against it. Whilst they look nice, hiding the screw heads away from view, the wood invariably gets damaged when removing the plug to get at the screw in cases such as this. I have to say that I have not regretted this decision.
This is the bulkhead with the bottom and starboard edges scraped back to bare wood and the epoxy brushed on. Again I have use the peel ply.
And here is the side bulkhead with the bottom batten similarly epoxied.
Now I have to wait for the epoxy to fully cure, not long in the current temperature, at which time the peel ply can be removed and the bulkhead put back into position and a fillet of thickened epoxy put over the join between the bulkhead and the hull.
Then it will be the turn of the starboard side which should be a lot easier since the bulkhead is made in one piece and not two.
We shall see.
Time for a cup of tea.