3/4" thick based on what? I have seen lots of speculation about deck thickness, but no authoritative citation.
There's absolutely no doubt, and never has been, that it's a steel deck.
Below I'm re-re-posting some images that have been posted here before, both by meself and Ohsin depicting the tank divisions. These are for only the Marmac barge, not the deck extensions. I've added an approximately 12' red circle for scale but its location in the fore-aft direction is anybody's guess.And then there's the dark spot approximately 1' in diameter just inside the cones and tape (Kabloona's picture above). That is at the edge of the Marmac barge. One might just hypothesize that it too is a hole.
Six portable welders and a dude.
FCC permit for CRS-8 transmitters:https://apps.fcc.gov/oetcf/els/reports/STA_Print.cfm?mode=current&application_seq=69496&RequestTimeout=1000ASDS location is given as 30.5 degrees N, 78.5 degrees W.Permit does not guarantee an ASDS landing attempt on CRS-8, but it is apparently an option if they can get the repairs done fast enough.
Like rocket catching barges? Got some time? Try punching in "marmac 303" or "marmac 304 in this link and hitting search. http://www.eagle.org/safenet/record/record_vesselsearchAmong other things you get inspection records and the type of steel used, which is 'ABS Grade A', which itself is a search term that will send you off to some interesting reading.
I'd be willing to bet that this really dark spot is a place where the decking had been extremely thoroughly washed. Perhaps some type of fluid came out of the debris and pooled here, and either discolored the deck or required a very thorough cleaning?
what seems to be being referred to as "the second hole" is a very dark area, somewhat similarly shaped to the obvious hole, just across the barge from the obvious hole. I've circled it in red. This area was covered by debris and tarps on the earlier aerial views, and seems to be one of the foci of the tire scuffs and drag marks that result from the piling up of the debris and its subsequent removal.
First stage took out...
Hole aligns to covered bollard box on sides(3rd from stern)
I was imagining MARMAC 300 getting some timbers lashed to the top, being submerged under OCISLY, and then triumphantly refloated, lifting OCISLY, to be the new temporary work area
@Mark ... With your model what should be the length of these compartments? See if it matches to those.