2004 Bavaria 32 Barrier Coat and Antifouling

[andrewj3]

I have a 2004 Bavaria 32. I have had the bottom soda blasted and would like advice on refinishing below the waterline.
1. What is a good  barrier coat
2. What is a good anti fouling for Boston and New England.
3. What type of treatment for the iron keel to prevent/seal corrosion before applying anti fouling?
4. What is recommended for the sail drive and folding propellor?
I would be very grateful for any recommendations.

[SorinCT]

Although i cannot comment on specifics of your product availability and sailing area particulars, i have seen people coat their keel with zinc-rich epoxy prior to antifouling and they have reported no rust since. Mine was also flaky last time i had it up and will do a full epoxy coating next haul-out for sure. I scrub the bottom every 3 years though...
It's recommended that you use antifouling specific for aluminum (sail drive, rudder bearing housings, etc).
What brands of marine coatings do you have available in your region?

[symphony2]

Have you considered Coppercoat? Having gone to the expense of blasting the hull it is well worth spending the extra on Coppercoat over a conventional antifoul. However you need to plan its application, particularly for the keel - although what follows applies to whichever coating you are applying. Coppercoat is an epoxy so does not need any barrier coat on GRP. Iron keels are problematic and it should have been epoxy coated immediately after blasting. Leaving it and then applying a coating is a waste of time unless you blast it clean again or the blaster has applied a good barrier coat to prevent rust from starting.

There is a huge choice of barrier coats for the hull before antifouling as well as a choice of antifoul itself. Be guided by what other people use in your area. What works in one place may not work in another plus what is on offer where you are will be different from say the UK.

Saildrive and propeller are much easier. For the saildrive housing use one of the coatings designed for aluminium . In Europe the most common are International Trilux Prop-O-Drev Spray on and Hempel Ecopower. Both are primer and top coat. You can also use this on your propeller, but Velox is better, although more complicated to apply. Do not use a copper based antifoul on the saildrive housing, nor within a 10cm radius of where the rudder stock exits the hull.

[Aloha Spirit]

in April 2020 I bought a 2007 42 Cruiser.  Bottom had many coats, peeling in areas and some rust on the keel (particularly on leading edge near partner which had me a bit concerned) so I decided to do a bottom job.  Unfortunately, I couldn't get anyone in time to blast it before my splash date so I did it the old fashioned way - hand scraper, ugh!.  On positive note, I lost over 150lbs of paint off bottom (that's just what I caught in HepaVac), lost 10lbs and gained some muscle mass.  But 110 manhours later here's what I did:
The barrier coat was in good shape so I sanded down to that, faired my through hulls and a plate around the saildrive rubber boot.  The keel took some work.  I ground down to shiny steel where necessary (particularly around the partner were I thought I had issues, but it ended up being just surface - keel bolts and partner adhesion still in great shape.  As Symphony2 said, you need to coat that right away.  I first used that jel etching primer, wash it off, wipe dry with alcohol and then epoxy coated keel.  Then I took my time to fair out keel paying close attention to leading/trailing edges.   (All West System epoxy/fillers).  Then I put 4 coats Petit Protect Epoxy Barrier coat on keel.  If you can get to it, you can start next coat right after the other so they chemically bond.  If not, you have to do a light sand in between so it keys together.  Once I had keel squared away.  I applied another 3 coats on entire bottom (including keel - the more the merrier when it comes to barrier coat on the keel), and then went straight into my first coat of bottom paint (again, so it chemically bonds with final barrier coat).  I used that still fairly new Petit Odyssey HD ablative.  Only 2 coats fairly thin.  Works pretty well in my area but you need to clean it about every 4-6 weeks or she'll get a little slime coat on her.  If I was racing her that would be every week.  Just a note, I hope in the next couple years I'll be taking her on extended cruise to the islands. Prior to that, I'll likely take that light coat of ablative down, add yet another couple coats of barrier and go with the Pettit Trinadad SR (or I think its the PRO now).  Has the highest copper content available. 
Lastly, the saildrive I cleaned up and painted with the barrier coat as well (except the small area where the zinc collar attaches - leave that OEM primer if its in good shape like mine was).  Then use the Interlux Trilux 33.  I tried a couple other things like zinc spray, Pettit spray, but that one seems to be the best. 
I'll post a couple pics of the job.  If there's something in particular your interested in, let me know, I probably have a closeup photo of it before/during/after.  Good luck.