I have used that type of transducer and several other Amel owners have as well. They are made by Airmar, and are known in their catalog as a "P79".
The only difference between the various brand labels for transducers like this is the connector on the end of the cable.
They work very well on a solid fiberglass hull boat like an Amel. On a cored hull--not so much.
, wrote :
Raymarine offers depth sounder that does not require a hole in the boat. It works through a fiberglass bottom.
Did anibody used it type?