Reginald P. Smithers III wrote:
JimH wrote:
"sherwindu" wrote in message
...
After pulling my boat from the Root River in Racine Wisconsin, I
noticed that
there
was an ugly band of black gunk at the waterline, especially at the
upstream side
of
the boat when it was in the slip. A power wash got the mud off, but
this band
of
gunk stayed on. I had the same problem last year, and had to rub
like hell with

all kinds of cleaners to get it off. Someone recommended using Tidy
Bowl as a
cleaner, possibly because it contains Muratic Acid. I know that
Muratic Acid is

used to clean and etch concrete, so I was wary to use it on my
fiberglass hull.
Was I correct about this? Is there a better way to clean off this
river junk?
I
have used Zud and other similar products, but they don't get
everything off and
require a lot of elbow grease. Some of this gunk is on the bottom
paint, as
well,
so I have to be careful not to dissolve that.

Sherwin


Bar Keepers Friend
http://yhst-55367440605114.stores.ya...barkefrpo.html


I would not use Bar Keepers friend or any of the other abrasive cleaners
on fiberglass, while it is a mild abrasive, I would be concerned it
would just make it harder to remove the gunk next year.




ps - after I sent the post, I wondered if Bar Keepers recommended it for
fiberglass boats. Bar Keepers recommend rubbing with the grain, which
to me is a red flag about being abrasive.

While they didn't actual recommend using the product on fiberglass,
"They said " Bar Keepers Friend has been used successfully to clean
fiberglass boats, bathtubs, and showers--especially where water stains
are a problem. Do not use hard rubbing."

If you decide to go route, do it very gently.