There is a great deal of misinformation about investing in treasure hunts. For example, many people have borderline accused Mel Fisher of fraud because the partnerships he formed and sold were only for 12 months. That was done to take advantage of an SEC loophole for one-year entities (otherwise, if there were more than 25 investors it had to be registered with the SEC - a very expensive proposition).
Some years ago I wrote an article for the old Treasure Quest Magazine about investing in treasure projects. I mention it because it's the only thing I've ever read on the topic, other than a chapter or two in Phil Olin's excellent Treasure; The Business & Technology (full disclosure - as always - I funded the first general printing of that landmark title).
Sunken treasure projects, in particular, are extraordinarily expensive. I've never seen the numbers, but I suggest the successful hunt for the SS John Berry lost money - despite finding at least 1,000,000 coins.
Barry Clifford's Whydah hunt was funded by a limited partnership underwritten by a Wall Street investment house. I'm sure those investors never recovered what they put into the deal.
Frank Pope's Dragon Sea touches on investing and returns. That is an excellent book in many respects.
As others have pointed out - there are generally several sides to every story. Don't be in too much of a hurry to draw conclusions until you've heard most of them.
Good luck to all,
~The Old Bookaroo