Gelcoat Stains

my3sons

Well-Known Member
SILVER Sponsor
Feb 24, 2009
3,037
Western NY (Lake Erie)
Boat Info
2004 400DB, Onan 9 kw Generator, Highfield RIB,
Engines
Cummins 6CTA M-3
We hauled the boat for the season earlier this week. We get a film that forms on the hull directly above both A/C discharge ports, we have seen this before but not as bad as this year.
I was able to get rid of them, but only by compounding the 2 areas, nothing in the way of cleaners that I had at the boat touched it. Had to go back the next day with my buffer and compound. Wondering what product others use to clean that off?
Anybody know what causes it?

Rear a/c discharge is on the bottom. Notice how there is a drip line down through the stain from the shower sump discharge port, as the stain is building over time, the drip must keep it washed off. Nothing I tried washed it off.
IMG_0550_LI.jpg


Forward a/c discharge.
IMG_0551_LI.jpg
 
i have used
mary kates on and off
biokleen hull cleaner

just keep it off your bottom paint fresh air and thin rubber gloves. works great.
I just spray it on a rag and wipe on and off, rince after with clean water. You will need to wax after that, it removes everything
 
I didn’t try on-off, but I did try FSR, it is what I use to remove the stain that forms just above the paint line and the stains from water with a lot of tannins.
No luck on this stain though.
I’ll try the on/off next time
 
So the dropper guard keeps the fog or mist or whatever it is from rising up and coating the hill above the thru Hull?
 
So the dropper guard keeps the fog or mist or whatever it is from rising up and coating the hill above the thru Hull?

the streak directly below the thru-hull would be eliminated and it's possible the mist rising up would be far enough away from the boat not to coat the hull...?
 
I didn’t try on-off, but I did try FSR, it is what I use to remove the stain that forms just above the paint line and the stains from water with a lot of tannins.
No luck on this stain though.
I’ll try the on/off next time

I used FSR on mine before, it worked though. I put it on and worked it with a towel, came back after it was pretty dry (maybe 5 mins), added more to it and rubbed it clean.
 
Regarding the Dripper Guard, do they eliminate staining or just not make it as bad? I imagine some of the stained water will drip and follow the guard toward the hull and still stain.
 
IMG_4230.JPG
Zing works every time on this. It is muriatic acid. (HCL) always have a small supply handy.
 
Regarding the Dripper Guard, do they eliminate staining or just not make it as bad? I imagine some of the stained water will drip and follow the guard toward the hull and still stain.
nope, it eliminated the streak on mine as well. It's made not to drip down the hull.
 
My Dripper Guard worked great until it blew off in rough seas. Made a comment on their FB page and they sent me new one which I haven't gotten around to installing yet...
 
My dripper guard has stopped the stains completely. I do get a little splash back on the boat. But it is minimal. I did have to silicone mine on. Assuming I didn't get all the wax off when I installed them.
 
Great feedback! I just ordered some to install this off season.
 
on my AC drains, i use clear 1/2" hose, sticks out maybe 3/4". works good....
I used to do this as well... It worked but I did notice that my air didn't work as efficiently as it did because it's pushing less water through my through hull. Just what my experience was that's all...
 
We hauled the boat for the season earlier this week. We get a film that forms on the hull directly above both A/C discharge ports, we have seen this before but not as bad as this year.

That's odd... We are in the same water and I don't get anything like that. In the pic you can see a solid clear stream about the first third of the way before it hits the water. So no mist or spray to rise. I put in the clear plastic tube this year and it disrupts the flow breaking up the stream sooner and I still get the drip mark like you have. I am going to get rid of the tubes this year and go back to original.
If you don't have a solid stream that could be what's causing the misting.

IMG_1127 - Copy (2) - Copy.jpg
 

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