Last summer I bought a pair of Pro Tech rubber fins from a local rep I work with. While they look flimsy, I found I was still able to track well, even during a race.
They’re also helpful in surfing shallow beach break where I can surf into very a few inches of water without worrying about hitting the bottom or damaging the fin box. In larger surf I haven’t noticed any loss of control.
Many prefer rubber and plastic fins for river paddling as most rivers are shallow and fins can be a problem in boulder gardens and shallow areas.
Kelp Beds and Milfoil:
Yesterday I paddled the Strait of Juan de Fuca near where we surfing WA State. The Strait is lined with miles of kelp beds sometimes 300 yards wide. I had to cross one of these sections to get to a rocky point of interest. Normally with a hard fin I’d be in trouble with catching the fin whether paddling forward or even more so backyards. The rubber fin skipped over the kelp never catching once. I use a coiled leash in these coastal environments where there’s only small surf. The coiled leash stays on the board and doesn’t catch obstructions below.