white spots on hull?

[seafox]

Alan's sanding recommendation will tell you.

[turkish6]

so i did a light sand using 80 grit by and and after a few runs through the white spots cleared up. So I am assuming I don't have a big issue?

[Alan Wheeler]

Doesn't sound like it. If they were blisters, they would have opened up and exposed a right mess.

[seafox]

If it was osmosis the sanding would have opened up a big wet hole. Sounds like you just sanded off something that has stained or attached itself to your hull. Osmosis blisters would have been a bump on the surface and sanding them would have produced a wet water saturated area.
Keep your money in your pocket

[turkish6]

I wish I had money in my pockets to keep .
But I am relieved we don't have a big problem on our hands.
Next question is.. Do you think its ok to leave that on there. or sould I sand it off?

[cabo_sailor]

If you take a small pocket knife and poke in the spot you should be able to tell if it is osmosis or hull blistering. If it is hull blistering the outer layer of gelcoat will pop and a distinctive vinegary odor will be apparent. If the spots are solid, its most likely not blistering.

[turkish6]

its defiantly not blistering. it most be just some sort of stain.

[Alan Wheeler]

Yep leave it on there. Paint the next coat of Anti-foul over top of it. I wish all paint was as easy as that. Usually the water jt blasting will remove what ever is loose and anything that doesn't come off, is good enough. Somewhere down the track, like maybe four or five seasons, the Anti-foul will get to the point were you need to scrap it back and start afresh.