[Cincy020]

I purchased my Catalina 22 this past summer and is in desperate need of bottom paint. The PO had applied once and had not re-applied in a number of years. Luckily, I do not see any signs of blistering, but some of the old pait is starting to give way, so re-applying next spring is a top priority. I did want to apply VC-17, but from what I have read, will not stick well to old paint. It seems that SR-21 has some of the same qualities as VC-17, as far as being easy to apply, low/no buildup, etc. However, I can not find if SR-21 can be applied on older paint that isn't compatable. Would this be an okay paint to put over old pait which is has been prepared (cleaned, etc.)? The boat is in fresh water, 6 months of the year.

Thanks.

 

[capt jgwinks]

I think the overcoating issue is mainly for performance. You wouldn't want to put a super smooth super slippery coating over a nasty rough surface, but there may be some paints that VC or SR might not adhere to. If your existing paint is flaking off you really should remove it, by sanding, scraping, and/or media blasting. Especially if you don't know what kind of paint it is.
VC17m is pretty much the standard bottom paint for freshwater sailboats, but I like the Pettit SR 21 (and West Marine FW21 which is the same thing) better. It has the same Teflon and anti-slime properties but has more copper. The bag of copper powder is larger and you have to mix it in a separate container because the powder won't fit in the can with the paint. Seems to go on smoother as well.

 

[i_amcdn]

Last spring while we were still on the hard, I asked some Hunter guys what they were going to use. VC17 was the answer 3 out of 4.

"oh that's good" says I...."you only have to do it every 3 years"
"Oh no...you do it every year" says them.
"Do you race?" says I.
"Only if we see another boat going the same direction" says them.

I didn't see the point in asking them if they could simply give me the extra cash they were all willing to part with solely for the sake of saying they used VC17.

I went back to my little boat and rolled on some Bottomkote XXX....in that clay red colour....for 1/3 the cost....each year.

I am non-standard in many ways.

 

[SHNOOL]

VC17 isn't the do all end all, but it IS a pretty simple bottom paint that does a nice job. None of these paints are worth a darn if you don't prep the bottom correctly.

The truly OCD racers use epoxy bottom. My boat is a slip filler most of the summer... some kind of active bottom paint is required for me... although our lake is a very low growth lake. VC17 is preferred, because clean-up at the end of the season can be done with a sponge. We have no pressure washers, or lift, or crane... so it's 5 minutes at the ramp with a sponge, and work is done.

Sadly if you had ablative on the bottom before, and it's failing, to get the bottom proper smooth again, you'll need to scrape/sand/barrier coat, or blast/sand/barrier...

Either way it's hard work (or expensive) and quite toxic. I've done it, but I won't do it again if I can avoid it (I'd be dragging the boat to a soda blaster first before I tried doing it again myself).

I like and still use VC17m.. not because it's fast, but because it works, and its easy to apply... and you can do it year over year, and it takes like 15-30 minutes to apply another coat.... and you can put on layer after layer for quite some years without it turning into a bumpy landscape. I know nothing of SR21, but imagine its very much like VC17m... But again, either would be sufficient in freshwater if you have a decent smooth barrier coated bottom, that is where ALL the work is.
Bottom before

Bottom stripped, sanded, and fairing beginning

Barrier

VC17m 4 coats, 2 red, 2 copper

 

[Fstbttms]

I purchased my Catalina 22 this past summer and is in desperate need of bottom paint. The PO had applied once and had not re-applied in a number of years. Luckily, I do not see any signs of blistering, but some of the old pait is starting to give way, so re-applying next spring is a top priority.

Anti fouling paint does not prevent blistering.

I can not find if SR-21 can be applied on older paint that isn't compatable. Would this be an okay paint to put over old pait which is has been prepared (cleaned, etc.)?

Vinyl paints (like VC17 or SR21) are only compatible with other vinyl paints. Using it over a non-vinyl product will result in a failure of the coating.

 

[kwaltersmi]

I've used VC for several years and have always been happy. I've never tried SR (or the WM equivalent) but might give them a try this coming spring since they are both a bit cheaper and are very similar.

Here's what Interlux says about using VC over existing antifouling paint:
Removal is best but if this is not possible, start sanding with 80 grade (grit)
paper and progressively sand with finer grades until the final sanding with 320 grade (grit). Remove sanding residue.

 

[Cincy020]

I'm not really concerned with performance issues with the paint because I do not race. I want something that will keep the bottom relatively clean, only using the boat once a week or so. Sounds like if I want to do it right, I could have quite a project on my hands here soon....

 

[Sanduskysailor]

Chemically they are both the same. Pettit uses a better anti-slime additive in their formula. I have used both interchangeably for years. No compatibility problems at all.

Use 90% isopropyl alcohol as a solvent. About a $1 a bottle at Walmart . I dilute the paint around 10% in the roller pan. Also use a squeeze ketchup bottle to apply to the roller. Keeps this stuff from evaporating too fast. 1 can should do it if you use a West Systems 7" foam roller. Don't use a regular roller. Solvent and paint will cause to disintegrate quickly. Seeing that you are Cincy. Don't put it on till next spring. Clean bottom first with soap and water. You can also wipe bottom with solvent soaked towel but really not needed.

 

[Barquito]

I would keep it simple, and stick with the ablative paint that is most likely already on the bottom. If it is in really bad shape, you need to scrape and sand. However, you don't really need to get everything off like you would if you were going to switch to VC-17. If you are willing to do some work mixing (the copper is difficult to get mixed in if it has been sitting a long time), you may get some great deals on bottom paint at this time of year.

 

[Cincy020]

I would keep it simple, and stick with the ablative paint that is most likely already on the bottom. If it is in really bad shape, you need to scrape and sand. However, you don't really need to get everything off like you would if you were going to switch to VC-17. If you are willing to do some work mixing (the copper is difficult to get mixed in if it has been sitting a long time), you may get some great deals on bottom paint at this time of year.

What would be an example of an albative that would already be on it? I was looking at a WM compatability sheet and looked like their CPP is compatable with all paints but VC17 and the like. Would that be a good bet?

 

[Barquito]

Like Fstbttms said:

Vinyl paints (like VC17 or SR21) are only compatible with other vinyl paints. Using it over a non-vinyl product will result in a failure of the coating.

I'm far from an expert on bottom paint, but, usually you can put any ablative on top of another. You can only put VC17 over an epoxy primer (that is on a bare hull), or other VC17.