The bottom edge on both of my hulls is very worn down. The paint is almost completely gone and at one point it has worn down to bare fiberglass. Time to do a bottom job?
Yes. When you can see exposed fiberglass, it is generally time to consider a bottom job.
If so, how does one go about doing a bottom job?
The basic process involves flipping the boat over and sanding the exposed fiberglass and worn down gelcoat and wiping with aceton. You want to rough up and clean the surface so you get good adhesion. Mask off the hull so you don't get resin drips on it. Laminate layers of 1" to 2" wide fiberglass tape to reinforce and build up any areas where the fiberglass has been worn down. Fair in the edges of the tape after the resin cures. Use putty (Bondo or Formula 27) to fill in the glass weave and any deep scratches in the existing gelcoat. Fair in the putty after it cures. Spray or brush on gelcoat (several layers as necessary) to build up the bottom. Fair in as necessary.
It is a fairly easy process but takes a while because much of your time is spent wating fairing the hull and waiting for resin to cure.