how much have you got?
257 million USD?
So at around 1 million NZD per barge, that would buy us around 388 barges (assuming we could buy that many at that price, which we wouldn't, but lets gloss over that). That's a total area of 721,292 sq/m. Woah, that's a lot of space for solar panels. Oh wait, we blew the budget on the barges. Darn.
Wait is that barge already leaking? Scrap the plan.
that’s conceptually adjacent to rafts
I did think of wood, and even reeds, like the ones they use to create the floating islands in lake Titicaca. I especially liked the sustainable process they have there, always adding new reeds to the top while the decaying/rotten reeds from the bottom end up fertilising the bed of the lake in a kind of circle of life