In answer to the questions from Terry and Jack, it is a fiberglass hull and
it is a modified V which is a planing hull. The boat is heavy, and does get
up on plane with the help of trim tabs. I could try it on the transom (no
swim platform) or with a water filled baggy in the bilge, but once it's in
the water, it stays until it's pulled for storage in the fall. If I put it
on the transom and it doesn't work, then it will have to stay there and be
re-done next year. I don't want the cost of pulling the boat and having a
thru-hull installed and then relaunched. It would cost me over $100 just to
have the boat hauled by a marina. This is not a trailerable boat. It has
an 11' beam and a flybridge and single inboard engine.

No one (except some reading I've done from transducer sellers, and that's
the hitch) seems to be saying that transom mount is out of the question.
Several marinas have told me it's OK but when I show them the literature
that comes with the products they sell they then back off and said it
"should" work but if I have them do it ($$) they know how and would "prep"
the boat before putting a transom mount on. I.e. not much confidence is
being inspired

Chet