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What is these brown stuff on my hull

Jul 15, 2020
5
Beneteau Oceanis Latchi Cyprus
During a recent cruise I ended up having some sort of rust or something coloring my hull. Anyone knows where this brown rust-looking discoloration is coming from and how to manage it? See picture
 

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Jul 5, 2011
505
Oday 28 Madison, CT
Possibly algae-based soils. Try some Clorox Clean up on a scrubbee. I see this when my boat sits out of the water over the winter. To get ready for spring I use MaryKate bottom cleaner which is very caustic but does the job You don't say where on your hull relative to water line so a photo might help.
 
Sep 25, 2008
5,790
Alden 50 Sarasota, Florida
It's not rust but rather staining from the water coming over the bow - a rather common problem and everyone has a favorite cleaning product, all of which work well to remove the stains. It's probably on the bow too.
 
Feb 26, 2004
21,206
Catalina 34 224 Maple Bay, BC, Canada
It's called tannin, from the water. I call it our mustache. ;)
FSR is the answer. Mary Kate O&O is toxic and should be banned from use. I tried once, in 2004, never again.
 
Feb 10, 2004
3,305
Hunter 40.5 East Greenwich, RI
I agree that it is tannin stains but it could be rust stains as well. Oxalic acid (think toilet bowl cleaner) will take either one off. So will FSR, On 'n Off (my favorite because it works so fast with minimal effort- use with caution per Stu).
 
Aug 2, 2005
1,011
Celebrity Class 19 Penn Yan, NY (Seneca Lake SP)
Tannin? My experience with water containing Tannin would be limited to fresh water lakes, rivers, or streams that have forests on their shores. Would sailing in Cyprus have that type of water conditions and vegetation? Would Tannin exist in saltwater?

I apologize in advance for this part of the post, but to offer a connection to the thread "It's Funny Friday" may I ask, "Were you sailing anywhere near a sewage treatment facility?"
 
May 27, 2004
1,499
Hunter 30_74-83 Ponce Inlet FL
Yes, a cypress swamp in your cruising area, even in salt ICW water, could cause a stain...
But I've never seen casual spray from an inland or waterway cruise cause that kind of staining on the deck.
I wonder if it rained while the OP was at anchor on a waterway, near a swamp?
 
May 24, 2004
6,429
CC 30 South Florida
Where did you cruise? It looks like rust, also looks like dried up dirt or dried up tanned water; you are in a better position to to determine which it is. Try soap and water and if it does not work a light rubbing with 1000 grade wet sand paper will do the trick.
 
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Jul 15, 2020
5
Beneteau Oceanis Latchi Cyprus
Tannin? My experience with water containing Tannin would be limited to fresh water lakes, rivers, or streams that have forests on their shores. Would sailing in Cyprus have that type of water conditions and vegetation? Would Tannin exist in saltwater?

I apologize in advance for this part of the post, but to offer a connection to the thread "It's Funny Friday" may I ask, "Were you sailing anywhere near a sewage treatment facility?"

savvas - I sailing in the Mediterranean. That stain was caused about 50 miles off the east coast of Rhodes.
 
Jul 15, 2020
5
Beneteau Oceanis Latchi Cyprus
savvas - I sailing in the Mediterranean. That stain was caused about 50 miles off the east coast of Rhodes.
 
Feb 26, 2004
21,206
Catalina 34 224 Maple Bay, BC, Canada
While the photo shows it on deck, that could be from going upwind and spray o'er the deck. Of course, we don't know what his bow looks like, so it could just only be on the deck. Either way, FSR or the old "any ole oxylitic acid" answer.
 
Jul 15, 2020
5
Beneteau Oceanis Latchi Cyprus
While the photo shows it on deck, that could be from going upwind and spray o'er the deck. Of course, we don't know what his bow looks like, so it could just only be on the deck. Either way, FSR or the old "any ole oxylitic acid" answer.
looks like rust from the pulpit welds.
Rust from pulpit welds is what I thought also as I am not familiar with any tannins. The hull only got Brown run spots around the Stanchion areas and not all over so I doubt is tannin. What’s interesting on my next leg yesterday from Rhodes to Simi island still sailing upwind with similar conditions did not generate any more of the brown stuff. If it is stanchion rust how to I take care of that?
 
Jul 15, 2020
5
Beneteau Oceanis Latchi Cyprus
While the photo shows it on deck, that could be from going upwind and spray o'er the deck. Of course, we don't know what his bow looks like, so it could just only be on the deck. Either way, FSR or the old "any ole oxylitic acid" answer.
Could it be a stainless/chrome cleaner I used before the trip on the stanchions?