When we started the boat there were 13 holes of various sizes drilled through the hull, mostly below the water line. From memory 6 were inlets of various purposes.
We have filled them all. We are hoping to have only one inlet hole in the hull. To make it possible the boatyard constructed a ‘manifold’ of stainless steel so that a single through hull inlet feeds the manifold which has 4 outlets.
A single 25mm inlet to supply all sea water needs.
The manifold is located under the floor just aft of the engine box. Each outlet from the manifold is separately controlled via a sea cock.
The sea water inlet manifold. Three outlets on top and one on the end.
The water lock for the engine exhaust is mounted just across the keel from the sea water inlet manifold. The boat yard experts advised us that the muffler should be located below the level of the engine exhaust manifold.
Water lock muffler for the engine