Hull cleaning help!

[Greenhand]

We have some kind of brown splash marks along the portside topsides. They just showed up one day after a big wind storm.

I tried just scrubbing, because that is where I always start.

I tried that magic eraser like product that you pay more money for at West Marine.

I tried FSP, because it seemed logical.

I tried waiting, because well, that worked on about half of them the last time this happened.

I tried a citrus heavy duty degreaser, because a neighbor thought it might be oil residue.

Today, I even went for the ON/OFF. It took off the tannins at the waterline pretty well, but didn't seem to have much effect on the brown spots.

What next??

[Vasco]

Oxalic acid.

[Cheechako]

Are you sure it's not oil? If so you need detergent. It happened to me big time passing thru the French Islands /Caribe. A govt ship was running around in circles dumping some sort of oily waste that was everywhere. When I got anchored after the days end the boat was covered with brown oily stuff.

[Greenhand]

Originally Posted by Cheechako

Are you sure it's not oil? If so you need detergent. It happened to me big time passing thru the French Islands /Caribe. A govt ship was running around in circles dumping some sort of oily waste that was everywhere. When I got anchored after the days end the boat was covered with brown oily stuff.

Like, dishsoap? I thought the degreaser was shoo in if it was oil, but I am willing to try something new. It certainly needs waxed after all this scrubbing, but I would like to actually get the stains off, first.

[wrwakefield]

Assuming you have a fiberglass hull that is not painted...

If the oxalic acid already recommended doesn't take care of it, try diluted phosphoric acid [e.g., 'Ospho' - available in box stores for derusting steel] or Davis FSR Gel Cleaner.

Ospho has always worked well for me on stubborn waterline stains. Brush some on; rinse it off.

Cheers!

Bill

[Greenhand]

Originally Posted by wrwakefield

Assuming you have a fiberglass hull that is not painted...

If the oxalic acid already recommended doesn't take care of it, try diluted phosphoric acid [e.g., 'Ospho' - available in box stores for derusting steel] or Davis FSR Gel Cleaner.

Ospho has always worked well for me on stubborn waterline stains. Brush some on; rinse it off.

Cheers!

Bill

Davis FSR was what I meant when I typed FSP in the original post.

[wrwakefield]

Originally Posted by Greenhand

Davis FSR was what I meant when I typed FSP in the original post.

Gotcha. I debated that and decided perhaps you meant TSP... which may also be worth a try.

However, as I mentioned, I would be very surprised if straight Ospho doesn't take care of it. It is pretty cheap too... just be cautious when storing it so any leaks are contained...

I hope this helps.

Cheers!

Bill

[Hudson Force]

If the "On-Off" didn't work, then none of the acid washes like oxalic or phosphoric acid will do the job. If it's oil based, then the detergent will likely be best, but I've found it takes some persistent scrubbing.

[wrwakefield]

Originally Posted by Hudson Force

If the "On-Off" didn't work, then none of the acid washes like oxalic or phosphoric acid will do the job. If it's oil based, then the detergent will likely be best, but I've found it takes some persistent scrubbing.

Thanks, Hudson.

I wasn't familiar with On/Off. I looked up the MSDS sheet and see it is composed of hydrochloric [20-25%], phosphoric [5-10%], and oxalic acids [1-5%].

By comparison, Ospho os 45% phosphoric acid- which may or may not make a difference in this case...

For the original poster, a couple of other cleaners we keep around that may be worth trying in this case include:

Krud Kutter [The general version is another box store item that works on lots of greasy messes- even wood pitch.] They also make many other specialty cleaners, one of which is their Tough Task Remover.

Slimy Grimy

Please let us know what ends up working for you, and best wishes getting it dealt with.

Cheers!

Bill

[a64pilot]

the on-off does wonders on tannic stains, just don't get it on you.

[Greenhand]

Originally Posted by a64pilot

the on-off does wonders on tannic stains, just don't get it on you.

It also did wonders on the rust stains that a recent rebedding project left behind. Evidently all of the previous owners were of the "if it leaks, tighten it down" camp, resulting in some very rusty, old bolts and compressed core

[Ribbit]

Would alcohol help?

Painters and decorators use it to clean up stains, etc., and it should be quite mild?

Of course if that doesn't work, the drinking type might help.

[Greenhand]

Originally Posted by Ribbit

Would alcohol help?

Painters and decorators use it to clean up stains, etc., and it should be quite mild?

Of course if that doesn't work, the drinking type might help.

I did consider that last option while at the store this morning...

Today's attempts, concentrated on a ~2'x2' swath:
-baking soda and dishsoap paste, with lots of elbow grease
-lemon juice
-lemon juice and baking soda, with lots more elbow grease
-heavy duty citrus degreaser, more and more elbow grease
-simple green, and, yes, elbow grease
-starbrite/attwood hull cleaner
-more Marykate on/off

[RaymondR]

Try hand cleaner. I use it to clean all sorts of things including printers ink and it often works well.

[Snowpetrel]

Ha just don't use detergents and acids at the same time! I wondered why nothing happened when I was scrubbing grime and rust stains of a 100 foot brigantine. The gang working in the bow of the dinghy ahead of us in the stern was using an alkaline detergent, and we were using phosphoric acid. Both were nicely neutralised by each other...

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