Should I paint the bottom?

[mnwnvc]

Use a good ablative bottom paint. It slowly wears away and leaves no build up. Easy to repaint.

[NoBones]

Depending on how active the marine growth is in that area
you will need to have a dive service clean it on a regular basis...

It will grow a beard with the bottom paint..

If you use it on a regular basis the beard will wear off underway to some degree...