The manuals supplied are not that good and on reflection if had spent the time to have downloaded them before buying the unit I may have realised that its operability may have been compromised by the boats design. They really seem suited to a boat that has a motor on a pod or similar arrangement. I am seriously considering an underhull mount and using a wedge to get the TX parallel to the waterline to compensate for the trim by the stern with the boat at low speed.
The only advice received from Lowrance was as the LSS-2 unit is only suitable for use at low speeds (>10 kph) transom mount it and trim the motor up out the way when using the SS and DS functions. I can see where that is going – new trim/tilt unit due to excessive use at some stage.