It looks like the source is where the outboard motor control cables pass through
in the cockpit foot well wall. There was just an open hole there and the rain was getting in.
That ought to be easy to fix. It just needs a cover that will keep the rain out instead of funneling it into the locker.
But where would that come from?
Who has the right size and shape in stock?
I couldn't find exactly what I thought I needed, so I decided to bite the bullet and make it instead.
This picture is the end result. Just a small cover to divert the rain water away from the hole in the wall.
This was made in one afternoon and evening - hand laid fiberglass...
Use your imagination!
This one is a soda bottle (filled with water to hold shape)
Three layers of glass cloth were laid on and wet out with West epoxy.
West System has a lot of information on how to mix and use their resins
as well as safety precautions.
Read the books and follow the directions.
It's not complicated, but mix ratios are important - so get it right!
Several short pieces of glass cloth (small scraps) were used to form the flange.
Then a couple more layers of cloth were added over the whole thing to cover all the edges
Wet out the covering layers and cover the layup with plastic wrap (epoxy won't stick to it).
The wood pieces press the flanges to make it nice and flat.
If I were going to make several parts like this, I'd probably cut a piece of plywood
into a "U" shape for this step, but for a one-off, just a couple of pieces of wood worked fine.
Then put some weight on the wood parts to compress the flange a bit while it cures.
pretty ugly surface.
We are not done yet.
Dremel tool with a 1/2" sanding drum.
Or just a stick with 60 grit sandpaper glued on one side?
Health warning - breathing fiberglass dust is not a good idea.
Wear a mask - and keep others away while grinding.
Also - vacuum up either while grinding (!) or immediately after.
Looks a little better now, doesn't it?
Gel coat is thick, heavy and brittle, so it doesn't take a lot of it.
But it provides excellent protection against UV damage from the sun.
It goes on like thick paint, and cures in a few minutes.
Once WELL cured, it can be sanded smooth (start about 220 grit for shaping
and 400 for smoothing.
Lastly a touch of polishing compound on the buffer and - it's ready to go to work.