Transducer replacement
Mr. Deutsch is right in that in most cases transducers are designed to be replaced without having to haul the boat. They usually fit inside their own specialized thru-hull so you might want to check that out.Transducers, as a rule, are not necessarily interchangeable between different units and depending upon the age of your now-deceased unit, it's like that technology has changed quite a bit and your existing 'ducer is not compatible with some of the newer units. Some modern units, too, use a transducer that can sound through the hull and don't require a thru-hull access. Some of the Garmin units, I believe, have that capability. You just glue them in place against the hull. You might want to check that out.