I am fascinated by the concept and engineering of this blind from 'Stump52' of KY, from the Refuge forums......
Here's a link to his write-up about the blind built by a guy in his 80's now.....that's been on this lake for years. You can tell the old guy had some understanding of floatation/ballast, construction, and logistics. Really amazing ideas to me, but obviously pretty routine for it's designer.
http://www.refugeforums.com/refuge/show ... ht=ballast
Here's a view on land:
It's basically a 16' x 8' x 5' x 1/2" steel box (the above view shows the 8' side of the gunner's box) with a long outrigger (everything to the left of the box in the photo).
If you think of a 'T'.......the boat bay is the stem of the 'T', and the gunner's box is the top of the 'T'.
You pull-up to the gate on the end of the outrigger section.......
open the gate.......

(view in 'dry-dock' / field)^^^
...........step-up onto a walkway (on top) that extends to the blind box.
You push the boat under the outrigger and close the gate. The area where the boat is moored appears to be lined with a rubber material - probably to protect the boat from the structure in choppy conditions and to keep any resulting splash from going into the boat. 'Stump52' says they get 2' swells on the lake sometimes.

^^^View of boat bay^^^ - catwalk on right side, above bay. I haven't figured-out what the vertical tube is, with the lid on it.........septic tank, maybe?
The concrete blocks on the front and back (16' long dimension - photos, above and below) sides of the blind box are ballast.......
.........and holds the steel box 'down' at a certain depth in the water.

^^^Front view of 16' long gunner's box ^^^
I think that's one of the motor mounts in the right foreground - there's another one on the left corner for dual motors to push this thing out onto the lake. I suspect the other box on this side of the blind is a dog box. Imagine what it took to figure-out the depths everything had to be and how much ballast would accomplish that, to make sure water didn't spill-in somewhere.....like the dog box and the tunnel under the skirt, over to the gunner's box for bird delivery.
The write-up indicates this blind is anchored by 1/2" steel galvanized cables to 5 tractor tires filled with concrete. That in itself would take some 'doing'. I've tried doing stuff from a boat.....and it's not easy. I think the lake-bed goes dry and then the water comes-up during the Winter months.
I realize this is probably more involved than most folks would attempt........but thought it worth sharing on here.
I have catalogued this in my brain for future reference.........

You can learn a lot from these old guys - I have no doubt (from this blind) he was very passionate about his waterfowling, and can just imagine some of the stories he has to tell.