Safe to use Products with Ablative Bottom Paint?

Skipper May 17, 2017 Ask The Skipper

Marie Worden asked:

I am trying to get the hard shell zebra mussel rings (or barnacle rings) off the fiberglass hull and outdrives. Can I use Green Genie to soften them so they will scrape off? Even where there is bottom paint, or only where there is no bottom paint? If I use Algex for outdrives, can I also use it on the spots on the hull where there are shells stuck on? Do I need both products, or can I just use the Algex? And could I use Algex to soften those spots on the bottom of the fiberglass hull even where there is bottom paint? Thanks.

Answer:

For your convenience, I’ve highlighted the hyperlinks. Click on the hyperlink to get more information about the selected product.

Either bottom cleaner will bight into the bottom paint and may cause streaks and even remove some of it. It’s unlikely that you have both Barnacles and Zebra Mussels. Barnacle are only in salt or brackish water and Zebra mussels are only in fresh water. If you have either attaching to the bottom paint, that means that the bottom paint is no longer effective and needs to be re-painted, so streaking or removing some of the top layer is not important.

You can try Algex on the bottom, but it is not as strong as Green Genie and you will have to use more and possibly multiple applications. Algex is recommended for outdrives because it will not attack the powder coated paint or the aluminum casting.

I suggest using Algex for the outdrive and Green Genie for the bottom. After apply VS721 to the outdrive to give you some protection against future fouling and wet sand the bottom paint and apply new paint. If you are planning to strip off the bottom paint and use VS721 on the hull instead of paint, now would be a good time to do that.

Thanks for your question,

Captain Aurora
Richard Kittar