Yellow stains on hull.

[MORNING LIGHT]

Every summer around the month of July, a lot yellow dirty stains begin to show on my Capri 26 1991. These stains are at waterline level and can go as high as 7or 8 inches and are quite uneven. I sail in fresh water but I know that this boat once was in Maryland. Does that have something to do with it. I do not know . I am always able to remove them at spring with a strong stuff but it might affect the gelcoat on the long run and it's not so pretty either. Any suggestion ?

Thanks

 

[RichH]

The yellow mustache is probably tannins from decaying vegetable matter in the water. Such is easily extracted with oxalic acid.

If you keep the gelcoat sealed with a good coat of wax (Collinite, etc.) the open pores of the gelcoat wont continually be stained by the tannins.

Power-buff the gel before waxing to remove surface roughness and 'dead/porous' gel, wax the hull by hand - dont use a buffer when waxing, it only removes the wax!!!! Apply the wax by hand - 'push' the wax *into* the hull gelcoat, dont just 'smear it' around on the surface; finish up by hand using a micro-fiber cloth.

 

[MORNING LIGHT]

Hi Rich

Usually, every spring I put at least 1 coumpound with a buffer and after that I put a coat of wax by hand. Could it be the compound that might
produce this effect or should I just wax it by hand and forget about the compound ?

 

[RichH]

I would doubt that your problem is from the compound ... as most boat compounds nowadays are made from micronized 'fossil diatoms' - essentially a 'glass'.

Ile Perrot being near Montréal, and where 'pollen season' is still in effect during July especially from softwood (pulpwood) pine/spruce trees ... it may be what youre seeing could be sticky pine tree pollen adhering to the hull, in addition to the tannins.
If your sailing venue is 'cedar water', then Id make the guess that its more tannins than pollen deposits.
With either possibility, oxalic acid will bleach the deposits.

Id also opt for a wax that has a high concentration of beeswax rather than just the usual straight Brazilian carnauba base wax ... as a 'trial' in sections, to see which works best and lasts the longest. Ditto a trial section with one of the new/modern hi-tech automotive 'polymer waxes'.

 

[MORNING LIGHT]

I forgot to tell you that when you pass your hand on the stains , you can not feel any deposit what so ever . The surface is really clean . it seems like some sort of reaction caused by something like it was painted in .

Thanks again

 

[LakeOntario270]

I get those stains on lake Ontario also. I found Starbrite Hull Cleaner takes it right off.

 

[Chenega]

Over the years I've had great luck with straight lemon juice in a spray bottle. Spray on- let stand for ten minutes and wash off with fresh water. Works every time without any scrubbing. Cheap and easy to find...