Bottom Sanding

[Babette04]

I read that mechanically sanding the bottom of my 04Beneteau323 is not advised due to the constructions.
Can someone explain this to me and is this true?
My mentor was a Nazi about keeping the layers of old paint to a minimum so this was my practice on my 76Tartan30

 

[Jackdaw]

Unlike your Tartan, a 2004 Beni will be constructed from Vinylester resin and therefor probably does not have an epoxy barrier coat. Than means any sanding will be taking off gelcoat.

 

[jdhohmann]

A nice long rigid scraper and lots of elbow grease works wonders. Once clean, be careful not to dig into gel coat, if you do make sure you get some resin and smooth out the nicks, then try sanding to get remainder off then slap that wonderful barrier coat on. Personally I would suggest a soft anti-fouling, sure you might have to do it every year or two, but you won't have to worry about the barrier coat again... I'm going on 14 years since I did the elbow grease method with a scraper, and it still looks fantastic

 

[Gunni]

What Beneteau does is specify the sanding grit (220) , in an effort to limit your ability to take off the vinylester seal on your hull laminate, and to manage their hull blister warranty - which BTW is now expired for your '04. So you use best practice. If you need to sand off an accumulation of flaking and peeling paint you will need to plan on starting back with a water-proof barrier coat primer. Nobody can remove bottom paint with 220 grit. You can remove your bottom paint old-school (80 grit), or have the hull blasted. In either case I would suggest an experienced professional. Your area Beneteau dealer should provide you with a list of recommended pros. Check references and experience, get the right outfit and you will be good. And yeah, your mentor was right, make sure you use the best bottom paint for your region, and your usage (single year haul, multiyear haul), and do not over-apply

 

[BigEasy]

If you go thru the trouble of sanding, scraping, or soda blasting to the gelcoat, When re coating be sure to apply a "flash coat" of paint that is a different color than your anti fouling paint. In the future you can use that 80 grit to sand until you see the "flash coat" . Won't have to worry about sanding into & damaging the gelcoat. You can do the same if barrier coating; apply a "flash coat". Over the barrier.

 

[RoyS]

How long does multi-season bottom paint last? I use paints with slime control and just touch up chips to limit build up. Is there a time limit on this paint where it should be repainted even if it is still not worn off?

 

[BigEasy]

Roy,
That's a difficult question to answer because of all the variables involved. Very much dependent on a given locale, use of ablative vs non ablative (epoxy)paints, winter haul out vs continuous service, % copper, etc. I use an ablative paint with high cu content in year round gulf coast temps; I usually get 2 to 3 years out of my bottom paint.