Maybe you can answer some 20th century questions:
- Are they available for ALL standard consumer grade FF, ie less than $1000 units?
There is nothing special or proprietary about a transducer. Airmar makes the transducers for most of the major players.
- - Given aluminum hull, do you use backer board with that transducer? Starboard epozied to the aluminum?
No backers required. You can get the units is SS, Bronze or Plastic housings
- - Is a low-cost plug available so you don't have to sell it with the boat??
No plugs. Why do you want to keep an old transducer? Good excuse for getting a better one for the new boat.
- - For a V or mod-V bottom, how do you correct for the angle?
They make ?tilted element? versions where the sensing element is mounted inside the housing at an angle. You buy the transducer that fits the deadrise of your boat
- - What is the average cost? ie is it reasonable for consumer level??
Depends on what you call consumer level. They start @ $200 and go up to a little over $1200 for the dual beam 1KW units.
- - I think it will be a while before we see flush mount Side Imaging.
Do a search on Furuno CH250 Searchlight Sonar