One has but to look toward the better parts of a movie like Waterworld or an experiment like Sealand to imagine the possibilities in a modular, mobile system capable of holding 1400 tons of cargo per barge (soil for farming operations, housing structures?) at costs incredibly far below the average island, or yacht, or WWII weapons platform off the coast of England, or custom-built waterborne structure. That these barges and towboats are already designed to house people for long periods and be modularly (dis)connectable on a large scale increases their potential utility, while every day more of these units are discarded, abandoned, fall to ravages of disrepair. Every major city along the Mississippi, the Ohio, and the Missouri rivers has a transport industry of significant size, and it is showing cracks at every stage of the process. I contend that this industry is ripe for pillaging and repurposing, and that it is only a matter of time before the river economy hits a startling bottom that, while destructive and fragmentary to the extreme for certain industries and industrial zones, could be very fruitful indeed for the intrepid seasteader.
While clearly sub-optimal from a jurisdictional and security perspective, as an economically-feasible boost-phase, it could provide invaluable learning opportunities.