The diesel engine exhaust went through the hull just on the water line, and had no sea cock on it. The sea cocks for the cockpit sewage was also on the waterline and were the originals from 1976.
I wanted to replace these, but also to move them up a bit, so that I could leave the sea cocks open when Matilda is in the home port. (I do close the sea cocks that are under the water line when I leave the boat unattended).
The first problem was the access. On the starboard side, there were 4 batteries that had to be removed in order to access the floor. This was rutten:
and the silencer from the diesel engine exhaust was bolted to it (the holes can be seen to the left). I cut the old seacocks and built a shelf for the silencer.
I used epoxi and glass fibre/carbon fibre to cover the old holes. The new ones were drilled some 15 cm higher. (The picture below is from the exhaust)
I bought stainless sea cocks and the end result looks like this on the outside (before painting the water line):
On the inside, like this:
Yes, I did replace the other sea cocks too, moving the sea water intake from below the gear box to the front of the engine for better access…
Magnuskrampell's Blog 
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