waterlinestains

[redhead78]

Hello, I have a yellowish brown stain along the waterline of my 1977 hull. Ok guys fight the impulse to your first thoughts, this is after I see the doctor,.....for the boat..... Any R/X to remove.....Red

[RichH]

Probably you have tannin and/or iron oxide staining.

Easiest, if above, removal is to apply oxalic acid for almost instantaneous 'bleaching' of the staining. The most cost effective source of oxalic acid is simple 'wood bleach' (containing pure oxalic crystals) - from hardware or paint stores. Just add the oxalic crystals to HOT water until no more oxalic dissolves in the HOT water ... then simply 'brush on'.

Tannins and soluble iron compounds readily penetrate the surface of POROUS gelcoat. If you have such staining, it means that you havent waxed your hull in a very long time; waxing fills in the surface porosity and prevents the penetration of the tanins/irons into the gel.
Oxalic acid may be very difficult to find in 'eco-crazy' areas/states (NJ, etc.); although, oxalic is commonly found in the non-edible parts of common vegetables - such as rhubarb, etc.

Caution: Oxalic acid rapidly enters across your skin and redeposits itself in the nephrons of your kidneys - forming very sharp/painful crystals (and kidney stones) ----- wear rubber gloves when using oxalic.

Oxalic Acid is found in many 'acid type toilet cleaners', common household cleansers (eg.: ZUD, BarkeepersFriend, etc.) and specialty detergents. ...... or you can buy oxalic containing cleaners in a boater's supply at 10-15X the hardware store price of oxalic.

[zeehag]

i have used clorox in a spray bottle and a scrubbing pad with excellent results.

[sailingdog]

Tape off the waterline, if the boat is on the hard, then get MaryKate On and Off GEL.

Wear gloves and eye protection as this is a nasty acid-based cleaner. Soak a rag with it... and hold it along the stained area for about 30 seconds or so... and move along... the staining should be taken care of. Rinse well with water.

DO NOT GET THIS STUFF ON THE BOTTOM PAINT. It will eat the copper-biocide and deactivate the paint where it touches it.

[T37SOLARE]

I'll second the MaryKate On and Off Gel.

I brushed it on with a throwaway paint brush and hosed it off, simple as that.

[Whissell]

We sail in water with heavy mineral content and get the same yellow lines. I used with great success the Mr. Clean erasure. What the hell, you've got nothing to lose, and they are environmentally safe. I then used McGuire restorer after.

[COOL]

FSR Fiber Glass Stain Remover.
Works realy well with little effort.
Wipe it on, wash it off.
Just be prepared to do the whole boat,
or you will have some bright white patches.

[sailingdog]

The Mr. Clean erasers will gradually abrade the gelcoat... the MaryKate On and Off is better for the finish.

Originally Posted by Whissell

We sail in water with heavy mineral content and get the same yellow lines. I used with great success the Mr. Clean erasure. What the hell, you've got nothing to lose, and they are environmentally safe. I then used McGuire restorer after.

[ottos]

I see you're in North Jersey. Where is your slip? Barnegat Bay or south, you are probably in cedar water. If so - follow what RichH said....

The water in the Pines is commonly called "cedar water." The Cohansey-Kirkwood aquifer is shallow in most areas, often less than 20 feet below the surface. (Patrick) The acidic waters (4.4 mean pH) are tea colored as a result of humates and a lack of organisms to decompose them, as well as by tannic acid present in plants, especially Atlantic White Cedar, and also by naturally forming iron present in the streams. These unique conditions have allowed the Pine barrens to host a number of unique plant and animal species.

What Is Cedar Water?

[heinzir]

I had a doh! moment today when I tried to remove the waterline stains on my boat. I didn't have any of the cleaners mentioned but I did try every soap, detergent, degreaser, and solvent I had available. Nothing worked. Then it hit me (not literally, thank goodness : Toilet Bowl Cleaner! It is basically a diluted acid. I brushed it on, let it sit a few minutes, wiped it off with a wet rag (so as not to drip on the bottom paint) and then rinsed with a hose. Worked like a charm and it's dirt cheap.

I should add that my topsides are painted with a two-part polyurethane and the bootstripe was painted on with hardware store enamel. The toilet bowl cleaner did not harm either. The few drops I did get on the fresh (two days old) bottom paint didn't seem to hurt it either.