For gosh sakes.
Whenever a thread comes up where someone inquires about a project like this, the "Tiller People" rise up like so many zombies and, ignoring much of what the OP has said, state that they
like tillers, tillers are good
, why don't you
want a tiller? as if they and their tillers have been somehow threatened by someone wanting a wheel. Great, you tiller folks like your tillers--have an annual meeting about it. Bring your tillers
Meanwhile, some like the wheel. Or in this case, the OP's wife wants a wheel. A perfectly fine reason to get a boat with a wheel. Conversion on that boat? Maybe not.