When you figure it out, let me know. That is the biggest pain there is
- getting the shaft :-) I've never been able to keep the growth off.
I assume you are in FL where the thick grows thickest!

One thing I started doing that seems to help a little is sort of a
strange thing. When I clean the bottom (and the shaft) I take surfboard
wax that I melt Cyan pepper into and rub it on the shaft. It doesn't
last that long but you can put it on quickly underwater and when I come
back, the job seems a lot easier. I don't know if I am imagining it
or if I have discovered the cure but I think it helps.

If you want to try this, here is what I did. I made a tinfoil bowl
inside a pan of water and put the wax and pepper in the tinfoil bowl to
melt. I just mixed it up and it seemed to work. I think a candle would
work or any paraffin but all I had was surfboard wax. The harder the
wax is, the better it would stick, I think.