Stop.
Bottom paint is expensive and a real pain to take off the old and
put on the new. It's not worth doing wrong (not many things are.)
The type of paint you put on over the old has to be compatible
or it won't work. Also the type of paint you choose to use
needs to match where you will use your boat and how
you will use it. (Will it be in the water all the time or trailered,
etc.)
Interlux puts out a nice little book titled "Boat Painting Guide &
Color Card." You can usually find one laying around the paint
isles of West Marine or Boat US. Can also find the
information at
www.yachtpaint.com and probably a bunch
of other places on the web. Doesn't mean you have to buy
Interlux - but it will explain the different types.
It's a little confusing to get your head around all the options, but
I think it's well worth your time to get the right paint. Maybe
what you already have is fine - but why take all the time to
scrape off the old and put on the new - if it might be the wrong
stuff for you?
I just happen to have two copies of the Interlux book. If you do
want to read it I'd be happy to send/give you one - send me
an email.
For my boat I choose the Micron CSC. Reasons:
-- I'm usually trailering so don't need super-duper "bio-lux" and
other fancy protection, just the basics.
-- Usually boating in the cooler waters of the northeast, so again
will not get lots of growth.
-- Still, there may be times I'll be in for a few weeks - and want to
minimize some growth.
-- Paint can be applied over my old paint. I still scrapped most of
the bottom to pretty much bare wood. But wanted something that
would work OK where I didn't get it all.
-- Dry time before launch is indefinite. Some paints have to get wet
within a certain time period of painting. I knew in our case it might
set a long time after painting.
-- Paint does not loose protective ability when out of water. Some
paints loose their anit-fouling ability when out of water for long
periods of time. Since we're trailering, only using some weekends,
and out all winter - that just wouldn't do for us.
-- More coates = more protection AND it's ok to do just a basic
clean and then add more coats.
But your situation may be different...lots of choices in bottom paint.