I doubt you can get the C80 to display the output of two transducers and differentiate them. You might ask that question on the Raymarine
forum. Obviously you could have a second dedicated transducer
and display not on the same SeaTalk
network as the C80. The C80 will display the depth
from your existing transducer
and the dedicated display will show the depth from the other transducer. Possibly a switch could be used to switch between the two transducers such that the C80 could display one or the other: however, that might cause problems for the SeaTalk
network. The Raymarine Forum is probably the best source for info of that kind.