Okay, I would be interested in knowing the cost of putting together such an expedition, for actual documentation, removal and renovation.
Lubliner.
No clue whatsoever!
Expensive, very expensive is all I could say for sure.
Their big coastal guns, so you'd have to have a decent size trackhoe out there, otherwise the tubes would be too heavy to pick up, which if the prices to rent one are similar to what they are here in NE Texas in New Orleans, it'd probably run between $700 and $1500 per day, (depending on size), and it'd probably take a minimum of two days. If you were to rent it after cleaning out all the foliage, it'd speed things up considerably. You'd need to use a barge to get it out there, so you'd need a big barge, not a small home made one.
(If this were six or seven years ago I could call up an uncle and get a barge from the Texas Gulf Coast, at a discount rate, and we could tow it to New Orleans as he had a factory making them, which would cut costs considerably, but he let a wife get the company in a divorce and took his remaining fortune to go gold mining in Colorado, and is still busy with lawsuits as a man got killed the first day of mining!)
Considering costs to rent a trackhoe and barge, (I've no idea the costs to rent a barge), I would guesstimate it'd take $5,000-$7,000 per day for 2 days. Plus if the number of guns left is the same as in the old photo, we'd need an 18-wheeler to haul them away from wherever in New Orleans we'd haul them to, (probably take 3 or 4 trips to get them all, all the tubes on one barge trip with the trackhoe would be risky), and for the 18-wheeler it'd be two or more trips hauling them, (too much weight to load all of them on one truck), so that would costs money, so all around.....
A lot, it'd cost a lot!
Getting them could cost around $15,000-$25,000 dollars minimum. At least that's my 5 a.m. guesstimating. If I had the connections I used to have it'd be cheaper though, but I know my dirt poor self couldn't afford it. Conceivably, it could be done for a
lot cheaper, if one abandoned the idea of backing a barge up to the battery and used a trackhoe, if we moved them the same way they did back in the 1800's, (tripod, chains ropes, and a lot of counterweights), but I'm honestly not sure how that'd be done to be honest. Maybe I'll consult my new period artillerist manual... but it'd involve a lot more backbreaking labor in snake infested waters and grounds, thus making accidents more possible if the area is anything like the legendary snake nightmare that is Fort St. Philip.
As for conservation? Going by the one modern phot, I'd say not really needed. It looks like oil, lot of cheap steel wool, gently used on the tubes to clean off the rust, (I'd be leery of using any power tools to clean rust off anything so old), and a bunch of black paint for when the rust is gone and they'd be like new. The guns look to be
remarkably well preserved for guns seemingly abandoned in such a toxic Gulf Coast region.
Sorry for the long post!