to sand or not to sand

[cyberpunx]

hi there just a wee quick one im doing my homework on preping for antifouling and some of the answers are saying sand down with an orbital sander some say dont sand down it's not worth the time and effort. as ive said in another post ive just started to scrape off the slime and white crap but in all honesty it isnt that thick im thinking maybe if i jet washed it it would come up better and then let dry and anti foul.?
any advice appreciated? p.s roughly how much would it be to get it grit blasted it's a 21ft daycruiser?
cheers john
or am i better sanding ?
D'OH

 

[PCUK]

NEVER dry sand antifouling, the dust is highly poisonous and will eventually kill you. Wet sand or slurry blast if you must. Otherwise scrape off loose areas, jet wash as you suggest and paint over. Don't worry if dry bits come off on the roller while painting, just roll them back over again and they will stick. This is normal practice and works fine.