Another variant
the rubbish patch target has plenty of plastic already, mostly below, some at the surface. We can recycle it.
Imagine a factory ship. It sucks in plastic at the front, processes it on board and spits it out the back as floating mirrors.
The process steps are:
filter out the plastic from the water, dump the water.
melt the plastic
colour the plastic and add antifouling and perhaps a little air as bubbles. A floating foam.
cool the plastic, recover the heat to use in 2.
extrude the plastic as a log and cut it into handy lengths
drop it over the stern as floating mirrors.
Solving two problems in one and saving transport and other costs. Service the factory ship with fuel and materials, swap crews, using another boat. Keep going.