Wonderful continent ya got there, Fish stealing bull sharks and Stealth Croc's!!! Makes me want to go diving..... Not! lol.
But seriously though, Wonderful images and as a Navy Aviation Anti Submarine Warfare Operator, with quals in accoustics and imaging radar, yes I would agree that the uneven surface kinda acts like the facits (sp?) on a stealth aircraft and scatter the Hi Freq signal. Shadows on stuff that absorb are the only clue they are there. The classic sailboat shot in the website shows a strong shadow of the forward sail but the sail itself is much less visible due to it's fabric nature.
I would assume with the lower freqs we will loose some resolution? Looking forward to my install of my 997c, Waiting for my twin Thru Hull Transducers and high speed kit to arrive at the dealer.
My new toy the 997 is going in: http://www.sonorantruck.com/detail-2003 ... 96334.html