Hi! Not sure if this is where I should be posting, but I am an casting and development assistant at Lucky Dog Films, and I am wondering if anyone knows of any companies that do underwater logging. You can email me back at this address, or call me at (240) 670-8496.
Can't tell you any names. But you could go about it from the opposite end, look for adds for salvaged underwater lumber and see if they can connect you. It seems to me I've seen adds for sunken heart pine in Fine Homebuilding magazine. There has been some log salvaging done in the Great Lakes as well.
There was an outfit out here that did it for awhile. I don't remember any names but met the owner of the company at an auction a few years back. You could try a search for Oregon/Washington underwater logging. I think they tried some out in Lake Washington and again somewhere down in Oregon. Good Luck!