Painting bottom of boat before going in water

[MaryRoseErie]

I was told that I need to paint the bottom of my O'Day 25 with antifouling paint every year before it goes in the water. I bought a can of it, 1 liter for about 47 dollars at West Marine. I saw that they had big cans for abotu 100, I think 4 liters? or three? I'm not sure. I was told that a 1 liter can will cover about a 20 foot boat. I figured I would try to stretch it.
I'm thinking though maybe I should get the larger can. It doesn't appear that last year's job was done well - it's not a good solid color, and the top foot or so wasn't painted. Also, my boat has a pretty big/fat bottom compared to others.
How important is this painting? Can I skimp?
-Jessica

[Siamese]

Need to know:
-what kind of paint did you buy
-where do you keep your boat
-how long is it in the water

[Siamese]

Assuming you're on Lake Erie, you probably are using VC17? Good stuff, and it goes on thin. If you search this site you'll find recent advice on how to apply it. I use about 2 cans of the stuff on my Catalina 309 (31 feet). I tend to have a little left over, which I save for the next season.

I do a thin coat every year.

I would say that no, you don't really want to skimp. Unless you like Zebra mussels and algae on the bottom of your boat. Go ahead and paint right up to the edge. Tape it with the blue tape, of course.

The cost of the vc17 brings pain, but if you want to feel better, just check with the marina and see what they'll charge to do it for you . You save.

Depending on how far you live from where your boat is, you might want to get a second can and see if you need to open it. If not, return it (checking store policy first, of course). If you need a can and a half, that's just the way it goes.

[Siamese]

Oh, and definitely check with your friend, the previous owner to see what they used on it. If you change paints, that's another whole can-o-worms.

[MarkCK]

Several questions/thoughts come to mind.

Is the paint you are using this year the same as last year's. If it isn't you might need to remove the old paint. This is not a fun job.

Don't skimp on the paint.

If done correctly it doesn't have to be done every year. Though if you are in a tropical climate you may have to clean it more than once a year.

[JimsCAL]

Some paints will retain their anti-fouling properties when hauled for the winter (copolymer ablative) and others do not (hard epoxy and cheaper ablatives). If not the first type, you'll need a fresh coat every spring.

[rhsanborn]

Here is a post where I asked a similar question a while ago.

DIY - Bottom Paint

The VC-17 needs to be redone every year if the boat is hauled, and if you want to repaint with something else, you need to completely remove the existing VC-17.

[MaryRoseErie]

The boat is kept in a marina year round, in the water from May-Oct, in Lake Erie.
No word on what paint it was. West Marine thinks it's similar to VC17 because it's gritty, not flaky.
I like the buy two cans and return if needed idea. The large can would be pointless anyways, as this stuff doesn't keep year to year, right?
Is it true that the paint dries in like 20 minutes?

[MarkCK]

The paint that I use requires 24-48 hours before putting it in the boat in the water.

[Sublime]

Originally Posted by MaryRoseErie

The boat is kept in a marina year round, in the water from May-Oct, in Lake Erie.
No word on what paint it was. West Marine thinks it's similar to VC17 because it's gritty, not flaky.
I like the buy two cans and return if needed idea. The large can would be pointless anyways, as this stuff doesn't keep year to year, right?
Is it true that the paint dries in like 20 minutes?

If the previous owner can't tell you what was used, you need to have someone knowledgable look at the paint and/or remove the old paint. You can put some paints over others but it depends on what the old paint is (Ex:You can do an ablative over an epoxy, but not the other way around).
Drying time will depend upon the environment. Lower temps and/or more humidity will lengthen drying times.