There's no better example of an extremely specialized barge than the Seaspan Harvester, a large vessel used to port large amounts of tree trunks in Canada on their way to be processed.
Because this boat is specially designed to make quick movements and carry a heavy cargo, specialty boat insurance rates may apply that account for the duration and the use of certain industrial vehicles.
In the YouTube video posted by Vitaly Petrukhin and published in the Telegraph, you can see this ship traveling in the waters laden with a heavy cargo of trunks.
Most of the ship consists of a long, flat storage space in which it can stack up these logs before setting out on its rounds, as well as a crane that can help in the loading process.
Then, the cool part: when it's time to dump this timber, the ship is actually able to roll itself slightly on its side so that all of the logs come tumbling out.
A blog post on Core77 discusses how this mechanism works: apparently it's down to the ballast system, which gives the boat the control it needs to perform this delicate procedure. The same post also describes how this isn't the only large scale ship transport system out there.
Large-scale cargo transport like this could very easily go wrong for your fleet if the ship has anything less than complete mastery of everything it has to transport and the processes needed to release them and move on its way. Boat insurance companies may need to be specifically contacted in order to guarantee the best practices.