Sudden Hull Discoloration

Went sailing in the ICW the other day and pulled boat up on a leeward, seaweed choked shore for about an hour. We sailed the boat back to the ramp and discovered the gelcoat below the waterline had a very obvious dark gray tint to it. Getting it home, I used a brush and soap on it.... no improvement. I then tried, one after the other, Comet, WD-40, 409, Limeaway, Fantastic.... none of which had any effect whatsoever on this sudden stain! I haven't tried Bar Keepers friend yet, but so far the only thing that makes an improvement is sandpaper. Very strange.

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Mims, FL

may or may not be the same type of stain but i get the black rain stains on the power boat all the time. I use softscrub with bleach and it comes right off.

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'73 hobie 16 restored 2011
'00 Seaswirl fishin boat

also a good coat of wax will help keep it off in the future. or at least make it easier to clean up.

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'73 hobie 16 restored 2011
'00 Seaswirl fishin boat

Thanks guys... I'll try both the soft scrub and the wax.

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Mims, FL

You need to use something with oxalic acid in it first - Barkeepers Friend, ZUD, OxyClean, etc.

Then put the wax on. Otherwise, you're just sealing the stain in.

If nothing else works try a little acetone on a small area and see if it does the trick.

The lake where I sail has a lot of red clay that stains the hulls. I use Star-Brite Hull Cleaner. Work well on all sorts of stains.

Another good product that is safe to use on gelcoat, etc. is "RustAid - Outdoor" from Home Depot or Lowes. I primarily use it to remove rust stains caused by irrigation sprinklers around my yard, but have also been using it for many years to clean the brown stains off the gelcoat, etc. of my powerboats and previous white hulled Hobie14T caused by exposure to organic acids as: tannic, humic and fulvic in our brackish water (in addition to rust stains).

The active ingredients in RustAid are: Hydrofluoric Acid and Oxalic Acid. I usually dilute it with water in a hand pump sprayer, spray it on, wait a few minutes and then rinse it off and the stain is gone.

Once you get rid of your gelcoat stains, it is best to seal the porous gelcoat with a wax so it will be less likely to stain again.

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Tim
84 H16
82 H16
87 H14T
Tortola Sails: 115222
Blue Prism Sails: 88863
Clearwater, FL

I swear by MaryKate On&Off. I've used it on my ski boat for years and more recently on my H18. It is fantastic for any kind of water-borne stain I've come across.

Found an MSDS sheet here It appears to be a witches brew of Hydrochloric, Phosphoric, and Oxalic acid. Feels real good when it drips down into scrapes and cuts, but my fingernails have never been cleaner!

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Jeff R
'88 H18 Jolly Mon
'10 F18 Closely Called
cramsailing.com

Anyone tried Ketchup? (not kidding) I hear it works as well as many commerical cleaners on fiberglass stains. Leave it on for a few minutes and them wipe it off.

No, but fresh sliced lemons or limes do work on most stains...the citric acid, much like the oxalic acid, does the trick

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Sheet In...Max Out
www.fleet297.org
sailflatlands at gmail dot com

Watch out using Acetone. You can damage your finish really quickly.

As long as it's gel coat (fully cured - the original finish on the boats), then acetone won't hurt it.

If it's paint, then all bets are off. Same with any vinyl stickers.

Matt Bounds is busy as the Primary Race Officer this week at the Hobie 16/20 North American Championships, yet he was up early this morning helping us out with our issues on this Forum. Mr. Bounds, I SALUTE YOU! On behalf of all us that you have helped over the years, THANK YOU.

By the way, I've used acetone for years with no adverse effects.

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Mark Van Doren
H16 Seabreeze #112205 (Richard Petty Signature Edition)
H14T Fantasia #47787
San Juan 28