I don't want to cheat, it's not about getting the stuff back, it's about bad game design. If there's not going to be a reasonable way to retrieve items from deep water, then why don't all items float? And don't give me the realism argument. We grow crops in 2 days, and trees in a week, there's no seasons, and magic is very real. The game is ridiculously unrealistic in so many other ways, floating nails isn't going to be killing anyone's "immersion".

EDIT: Oh, and I can have a cargo container loaded with over 1000 pounds of metal, and that'll float. So don't tell me "muh realism" for sinking nails.