Playing along with their heartfelt theory for a minute ... look at the "sonar target" they want to find again, and what they think it represents - our favorite Electra, pranged into the ocean floor vertically, with one wing nearby. About 200 feet nearby, according to the scale on the sonar image.
Think about that.
Assume that a wing does separate from the fuselage at the time of ditching. Or heck, even as the plane is on its way down to the seafloor. A partial wing weighs a lot less than the rest of the aircraft. Fluid physics tells you that those two pieces are going to behave quite differently on the way down, with one primarily a flat object and subject to all kinds of "planing" or "spiraling/fluttering" motions, and the other of a shape that might lend itself to some kind of "planing," or going sideways as much as it goes down. But neither one is going to fall straight down to the ocean floor 17,000 feet below.
And the odds of both pieces landing within a few hundred feet of each other at the end of their 17,000-foot journey? To steal a line from one of TIGHAR's expert witnesses, "vanishingly small."
Or so it seems to me. Everyone is free to believe what they want to believe.
LTM, who finds dry paint really interesting right now,
TIGHAR No. 2189 CER
P.S. - Their model Electra looks like the old Willams Brothers kit to me; someone didn't do a very good job filling in the centerline fuselage seam.