A68 (replaced A67) and older thru hull transducer

[Chuck - Raymarine - Moderator]

Chris,

Depth sounding products are dependent upon a non-aerated flow of water across the face of the depth transducer. Conditions such as backing down the engine or transiting a heavily aerated wake will cause the symptom reported. While less likely, it is possible that the performance of the transducer may play a role in the symptom reported. Power output to the transducer is also a factor in the performance of sounding products operating under such conditions. Depth instruments transmit relatively low power via the interfaced transducer than do fishfinding products which are less correspondingly less susceptible to the conditions described ... particularly that of crossing another vessel's wake.