Trolling motor shaft lenght

[eye1]

Wondering if a 42" shaft on a transom electric is going to be long enough on a boat with a 25" transome. I wanted a 50" but they seem to be almost impossible to come by . Seems like everything out there 42" . The only 50" that would seem to be available would be the Great White by MotorGuide but with the sealed electronics I'm not sure if it would b possible to turn the head around on the shaft for backtrolling. Any suggestions ?

Thanks

[The Eyes_Have it]

If it's going on the transom, I would think 42" would be plenty. The bow would be a dif. story