I'm guessing that you're underestimating the cost of drag ... tailing a 300 sq meter "boat" would probably require more energy than it could produce. I have no data, and haven't done any back of the napkin calculations to back up my stance ... but just look at the speed difference between a monohull vs a catamaran vs a foil sailboat. Reducing the contact area with the water (and thus reducing drag) is _everything_.
Drag increases with the square of velocity [1]. Some of the ships might be able to travel much slower? I keep asking for sources because dismissals out of appeal to obviousness are so ubiquitous.
Edit: Admittedly, you may be right, but without even back-of-the-envelope calculations, and with the assumption that these boats must go as fast as possible, I don't know why.
I too freely admit that you might be right as well (if the assumption of speed can be dismissed) ... lol, this feels like it would be perfect fodder for one of those physics youtube channels that answers channels, or perhaps XKCD's https://what-if.xkcd.com/
