Thanks for the expanded knowledge on the "sonic speed hose".  I always thought the idea of chafe protection was a bit overdone by encasing the cable in a hose, but your explanation makes perfect sense of the the Amel "belt and suspenders" type of design.

Still hope Olivier will chime in on the details of sonic speed transducer replacement as that is the only item on my boat that doesn't work to the level as the day she was built and I would like to remedy that if at all possible. 

All the best to Joel, Olivier, Bill, Kent and everyone else on this invaluable forum. 

Gary Silver

s/v Liahona,  keeping company with s/v Brava in St. Thomas