Disc pattern on hull

I've been sailing for a while now and wanted a little easy thing to drop in the water, safely push to the edge, teach some friends how to sail, etc -- so I bought this Hobie 16 for $400 after making sure the hull didn't have any soft spots, etc.

It does, though, have this weird lenticular pattern on almost all parts of the hull. Does anyone know what this is from? How serious is it? How do I remove it?

Image Gallery Here (Imgur)

Looks like that boat sat in the water for a long time resulting in damage to the gelcoat. Hobies are not intended to be stored afloat for long periods of time.

If the hulls are still solid, then it should be ok to sail, but I wouldn’t be surprised if they absorbed water and weigh 200lbs each now. You might want to install a 4” port in each deck to allow the hulls to ventillate when not sailing.

Anyway, I would use a sander and knock off all the damaged gelcoat and then brush on some marine paint to seal it up. It won’t be the prettiest, but should get you on the water.

sm

Below the water line, you can actually see the fabric of the fiberglass. As SRM says, I'd sand off the circles and repaint the whole thing. I'm thinking it's not worth the effort of putting on gelcoat, but you need something to protect the fiberglass from water intrusion.

You can get an idea whether the hulls have picked up a lot of absorbed water by picking up one side at the bow and then pick up from the same position a new boat.

Jim Clark-Dawe

those are osmotic blisters. Google it.