Bottom Stains
- Thread starter SqPeg
- Start date
From afar, my guess is that is a tannin stain created by leaves in the water and then splashing up against the topsides.
Staining appears to be from tannin in fresh water or possibly some algae. All the wax in the world probably won't prevent it.
With a smaller boat, just haul out and use a spray bottle with SnoBowl, sponge and rinse. It will come right off.
A bigger boat is another issue. Winter haulout is probably the only time to get at it. It needs to be done while the hull is still wet. The yard would normally use a low pressure steam cleaner to do the job. Bottom paint helps the majority of the situation. Above the bottom paint is another story.
With a smaller boat, just haul out and use a spray bottle with SnoBowl, sponge and rinse. It will come right off.
A bigger boat is another issue. Winter haulout is probably the only time to get at it. It needs to be done while the hull is still wet. The yard would normally use a low pressure steam cleaner to do the job. Bottom paint helps the majority of the situation. Above the bottom paint is another story.
We get something similar but not as bad from the water splashing on the hull. You can get "On and Off" at west marine that will take it off. Or if you have a pool the acid you use to raise your PH is basically the same thing and cheaper. Be sure to rinse it off good after using it.
these stains are found everywhere. i cleaned a 26 columbia with clorox n elbow grease-- fuggeddaboudid..aint doin that again.
in some areas the stain is petroleum based, in some areas a mix of petroleum and algae, and many inland waterways have tannin to mix with algae and such.
i have the diver clean water line when i have boat dived for periodic cleaning.
in some areas the stain is petroleum based, in some areas a mix of petroleum and algae, and many inland waterways have tannin to mix with algae and such.
i have the diver clean water line when i have boat dived for periodic cleaning.
I don't believe it has to be "water wet". I use the On&Off. Though from the dock you can squeeze the bottle to shoot onto the hull, I prefer from the deck, hold the nozzle against the hull above the stain and move it horizontally so make a "sheeting" action. Do it about as long a section as you can reach. You could use a long-handled deck brush to move it around for complete coverage. By the time you step ashore and pick up the hose to hose it off, the stain will be gone. This O&O is caustic, about like battery acid, so be careful. I just got a garden sprayer for 10 bucks to use to hose the O&O on. Have not used it yet.
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I can second what Ron said. I use a garden sprayer from the deck and you want either a slight breeze or moving quick without breathing it in. It will take off the stain, bottom paint, some rust on stainless, wine, fingerprints, and other stuff dropped on the deck (wrecks aluminum). My wife is usually on the hose at a distance to follow me when the stain disappears. Use all precautions.
All U Get
My experience is that that will NOT occur on a waxed hull, only happens when the wax wears off.
O&O is a product that is very aggressive, although as Ron explains, his technique works quite well. I tried it once, and agree with the "battery acid" comment! I threw the rest of it out. I use FSR gel on an automobile windshield squeegee sponge. Does the same thing: wipes the "mustache" off with no rubbing at all.
Do a search on "mustache" - this has been discussed many times before.
Any acid based cleaner will remove the algae/tannin quite easily. I use diluted commercial toilet bowl cleaner(usually has HCL), available at any restaurant supply such as Smart and Final. It is very inexpensive. If you're bio freaky, use rubber gloves a big sponge and two buckets... one with water and a few capfuls of cleaner and one for rinse... but remember.. it's toilet cleaner and will dilute enough to be harmless. Otherwise, a bucket, a long handled pot brush and a rinsing hose will make the job a snap.
On and Off will remove bottom paint. I thought I was being careful this past Fall, and rinsing right away, but some got around the bow onto the opposite side. Please don't look at the wavy waterline up at the bow 
Maine Sail recommends taping off the bottom with sheet plastic hanging down over any trailer, etc, using heavy duty rubber gloves, a tyvek painting suit, and goggles. For the light freshwater stains I get an inch or two above the paint line, I've been fine with a blue sponge/scrubby pad, with O&O applied right out of the bottle, and then rinsed with the hose after the stain has faded.
Other have recommended "The Works" bathroom cleaner. Again, it's all about the acid.
I have read that chlorine bleach is not good for fiberglass. This was from a fiberglass supply rep quoted in an article. Seeing how well oxalic acid/On and Off/acid bathroom cleaner works, I would not bother with chlorine.
Maine Sail recommends taping off the bottom with sheet plastic hanging down over any trailer, etc, using heavy duty rubber gloves, a tyvek painting suit, and goggles. For the light freshwater stains I get an inch or two above the paint line, I've been fine with a blue sponge/scrubby pad, with O&O applied right out of the bottle, and then rinsed with the hose after the stain has faded.
Other have recommended "The Works" bathroom cleaner. Again, it's all about the acid.
I have read that chlorine bleach is not good for fiberglass. This was from a fiberglass supply rep quoted in an article. Seeing how well oxalic acid/On and Off/acid bathroom cleaner works, I would not bother with chlorine.
Looks like tannin stains to me. I get them all the time, my house and dock are surrounded by mangroves which at certain times of year even stain the water brown.
FSR works the best, just wipe it on and leave it a while and the the stains disappear don't even have to rinse it off although I do as it takes off a lot of wax and then just put on some wax.
FSR works the best, just wipe it on and leave it a while and the the stains disappear don't even have to rinse it off although I do as it takes off a lot of wax and then just put on some wax.
I too use fiberglass stain remover by Aurora. It is as lots have said acid based and works great without scrubbing. The problem is that when it runs down, it will take off ablative bottom paint too. I finally read all the directions and Aurora recommends using a small paint roller to apply it and that gives you much more control. just roll it on the stains, wait a few minutes, and hose it off.
Last time I was on the dirt pile, I used Barkeepers friend. You can buy it in a liquid, and with a minimum of rubbing with a brush it came spotless. I recollect I did the entire boat in about forty five minutes..
I've posted this general obserbation several times through the years.
As already suggested in this thread >> tanin stains.
It's really a simple fix. Any product that has oxylic acid in it will remove. (However, I am not sure if your recent wax job is a barrier to prevent the oxylic acid to get to the stains.)
For only $1, the below url links to a product. Before I wax, I saturate a paper towel with it and then wipe on the hull. Might take a few applications to remove the yellow/brown stains and get the surface back near the original gelcoat white. When done with one side, I just start again on the other. Here's a pic of what this product did after the first time I experimentally applied it to the stained area on the aft section of my hull.
Also, is that over time, hard water does leave mineral deposits in all the micro pores of an oxidized gelcoat surface. I think that compounding with rubbing compounds or even say 600 grit wet/dry paper won't remove these deposots well enough. Oxylic acid does disolve them away. Then the compound/buff and wax process will turn out much better.
http://www.dollartree.com/The-Works-16-oz-Tub-Shower-Cleaner/p6065/index.pro
As already suggested in this thread >> tanin stains.
It's really a simple fix. Any product that has oxylic acid in it will remove. (However, I am not sure if your recent wax job is a barrier to prevent the oxylic acid to get to the stains.)
For only $1, the below url links to a product. Before I wax, I saturate a paper towel with it and then wipe on the hull. Might take a few applications to remove the yellow/brown stains and get the surface back near the original gelcoat white. When done with one side, I just start again on the other. Here's a pic of what this product did after the first time I experimentally applied it to the stained area on the aft section of my hull.
Also, is that over time, hard water does leave mineral deposits in all the micro pores of an oxidized gelcoat surface. I think that compounding with rubbing compounds or even say 600 grit wet/dry paper won't remove these deposots well enough. Oxylic acid does disolve them away. Then the compound/buff and wax process will turn out much better.
http://www.dollartree.com/The-Works-16-oz-Tub-Shower-Cleaner/p6065/index.pro
