Hi emmo. Well firstly to the hole. Two ways you can do this. You can use a diamond hole saw. This cuts a very nice clean hole, but is the most expensive approach for a one off hole. Or you can use a small masonry drill and drill through a series of holes in the area the one big one will take up. Then simply chip away the concrete and use side cutters to cut the steel
. Ummm, that would be BIG side cutters.
For the sounder transducer, you most likely will need a block to level the trany. Shape it like a boat hull
. Infact the trany will most likely be that shape anyway, so copy it with the wood. The wooden block is cut one side to fit against the hull, so as the bottom side is level for the trany to fit against.
Another way to do this is to find away to hold the trany level and then build around it with epoxy
mortar. The epoxy mortar will also do the sealing job as well. But the trany is in there for keeps if you do it this way. Or you can apply a grease around the trany to act as a release agent so as you can remove it when the epoxy has cured. Then use a mastic sealant
to seal it back in to the hole.
And that brings me to the sealant
, use a mastic, which is a sealant that does not harden. You can also use a Urathane Adhesive
sealant, but what ever you use, make sure it remains plyable so as it moves with expansion and contraction of the hull, and so you can remove the trany in future years.
Does that help???