Why bottom paint?

[AKBASSKING]

In australia, we have this new product, that to me it appears like lanoline with fine copper powder mixed in it.. Lanoline is a well known protector for trailers etc.. As its winter here i have not tried it yet, but have got 2 jars of the stuff to test very soon. Its very cheap, and you can put it on and take it of at home in 1 or 2 hours. The great thing about this is once you put it on.. you finished for the summer, you can take it completely off with a pressure washer and/or citric acid (so resale value is high because looks as though you never had bottom paint). It goes on paper thin, and can be used on fiberglass aluminium stainless etc. From comments i have heard it works great.. only thing i am not sure of, is how well it holds when you go 40knts.. on slower boats i think would be perfect. I have put some on a knife blade, then put it under the tap fully opened, and it seems to hold very well. Should find out in a few months when putting the new boat in the water (sydney harbour - salt water)

Please lets us know how your tests go!

 

[tobnpr]

Bottom coat is a hard, non-ablative paint. As soon as you get a little slime on the paint from non-use, Bottom coat is almost useless because the antifouling particles are covered up and cannot do their job. Every geographical location is different so I can't say how long a boat can sit in Va, but down here, commercial boats that are used daily or every few days all use hard paint with great success. Pleasure boaters who will let a boat sit for a couple of weeks have terrible luck with hard paints and all use ablatives.

Which works best under particular circumstances still confuses me (though that's easy enough to do, anyway). I had a bottom job done in Feb '07 with Sea Hawk ablative. I wasn't overly impressed with it's performance in my instance during the summer months- no hard growth, but lots of slime after just a week. The entire bottom "failed" last November (loss of adhesion from a paint layer probably fifteen years old) and I sandblasted/barrier coated the bottom. Sea Hawk paints was really cool about it, and "donated" the paint to re-do the job even though it wasn't their responsibility. This time I went back to the epoxy; I was told that the ablative paints work best on boats that are used regularly. Without use, the coating doesn't slough as it's designed to do. You are spot on about too much slime rendering the paint ineffective. Sea Hawk states in their warranty that monthly maintenance (scrubbing) is required. Failing to do so can render the paint ineffective and void the warranty.

BTW, I'll mention that the first time the yard screwed up and used the same ablative on the running gear as the boat. Ablatives won't last on gear; epoxy must be used.

 

[mrsrobinson]

Does a monthly diver scrubbing/scraping affect the performance of hard or alblative? If alblative is meant to 'peel away' with use, and a diver is regulalry scraping, that makes me think the diver is scarping the paint off too.

I cannot report on how well our Interlux hard bottom paint is doing in salt water (she did great in fresh) as she has only been there 6+ weeks. I'll ask the diver after this weeks diving what he thinks.

What prompted this post was seeing what our trim tabs looked like after only 6+ weeks. They have growth all over them, which shocked me.