So I have a buddy who bought one of these boats last year (21' Bankes Goliath)....mostly for duck hunting...but wants to use it for fishing as well. He had a Lowrance Elite 7 Chirp installed with a thru hull transducer...he is complaining about lots of interference in traditional 2d and the downscan is basically unreadable. The bow of the boat is Kevlar reinforced but the stern is not (where the ducer is currently mounted). Does anyone have experience in thru hull ducer mounting/placement/operation. I told him that we could get on water and play with it, adjust the frequencies etc. (which he said he already did, with nothing working better)...but if he wanted clarity to simply switch to a traditional exterior stern mounted ducer. Thoughts?