For that type of submersible barge the USS Cole is a very light weight, but awkward shape. They are normally used to transport completed top-sides modules of offshore platforms from construction yard to the offshore installation site, some have the capacity for 25,000 tonnes. For ocean passages with a heavy deck-load these barges are amazingly stable, out of yards in Korea and China, the grillage and seafastenings have to be able to withstand typhoon conditions.

If you take the upper case H and view that as the offshore platform, the barge manouevres between the upper two columns and them submerges to mate the topsides module with the structure. Depending on the design engineering, this type of installation is possible in seastates up to Hs 2m (Significant wave height of 6.6 feet, or maximum wave height of just over 11 feet).