Looking for info on narrower beam transducers for deep water bottom contour recording/mapping. The 20 degree cone that came with my HB598ci HD SI covers and averages too much bottom area. My past lake mapping has been under 100 feet, but lakes I want to do are up to 1,200 feet. At that depth, the 20 degree will miss a lot of detail. Before wasting mapping time and gas, I would like to find out what is available.
Web searches, so far, have not yielded much info.
Thanks for any help.
Lou