vertical black stains on topsides

C

ColinR

Well-Known Member
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23 Oct 2001
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www.victoriashadow.co.uk
I suspect they are caused by my black anodised toerail although they seem common enough on other boats that dont have this. They look like lots of dribbles of water down the tosides have left a grey deposit on the gelcoat. Its more of a problem in the yard over winter. I've tried most of the gelcoat stain removers and cleaners over the years with no real effect, and always resort to elbow grease and a plastic washing-up scourer, which I'm sure makes matters worse in the long run as it abrades the surface sightly and leaves a better surface for future stains. Even Y10 which is brilliant on waterline stains is no good. Any suggestions?

Colin

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Guessing here but perhaps this is due to electrolytic action where you have stainless bolts/screws through the aluminium toerail. The resulting white goo does tend to streak pale grey, perhaps increased by the black anodising. If you can see where the marks are coming down from maybe that would confirm, and you can do something to cut off the source.

For cleaning off aluminium oxide stains, possibly a lye (sodium hydroxide) based product might work - for example a heavy duty oven cleaner. Never tried it on GRP though. DEFINITELY one for testing on a small hidden patch first.

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Re: 2 suggestions...

Black Streak Remover is a superb product. We use it for all topsides and coachroof cleaning nowadays. It's completely safe (EDTA is used as a food additive) and requires no effort.

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had the same and Blackstain Remover did not work for me as well. Got sick of it and added a U shaped piece of aluminium (upside down) which came in 4m long segments and epoxied it under the toerail. Now the water collects there and drips harmlessly from the outer open end of the U directly into the sea :))). My ellbows recovered greatly since I did it.


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My boat was covered in them. Dont think there is a short answer having used all the cleaners known to man or beast. Only way I've found is. Wash with soap and water, four or five times, power wash in between. Then use the super dooper special, no effort, shifts everything at a stroke. (the bills just come from the chandlers £28 stuff) About five times. Now if you look carefully theres a bit that looks better. So carry on like this all day and maybe tomorrow. Then get some different stuff that seems to take off the marks that the other stuf fails misserably with, Then resort to the green cheap scrubby washing up thingy that takes most marks off without effort and no scratches. Which if you've any sence, you have been using all the time. Repeat process. Polish. Not with the stuff you have, but with other stuff in chandelers. Discover that the new stuff is complete crap and get some more. Last week International stuff seemed to work quite well. Hope this helps!!

<hr width=100% size=1> <font color=blue> Haydn
 
When you get it clean......

& the "Black Stain Remover" needs around 16C to work, regularly wax your hull to prevent this rain borne pollution from sticking. It also gives a little protection from minor abrasions & scuffs. The diehards will tell you to NEVER use silicone wax on boat hulls just in case you ever need to paint it but how many people do you know who have re-painted their boats? Anyway who says you have a duty to some owner two or three down the line? It's your investment NOW that YOU are interested in, he can get it chemically cleaned before he paints it and a good yard will do this anyway.

There are four old boats of mine out there which looked pristine at sale time and I used Turtle Minute Wax on their hulls three times a year doing a double treatment in the spring.

Steve Cronin

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Autoglym car polish. try it - it's brilliant for streaks, diesel spills etc. I do all the hull and topsides at start of season - wipe on, wipe off. £5 a bottle to do entire 30 footer.

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