I heard today that Swafega is the same stuff as the Y10 stuff used to clean up the yellow stain around the waterline ... before I go out and buy some swafega has anyone else heard/tried it?
Y10 had a reputation that it didn't work in winter temperatures - needed about 15 degrees C to be effective. There are several products containing oxalic acid that work well for this purpose, I use a Boat Life one but plenty of others. Or you can buy oxalic acid from a pharmacy or on-line and make up your own. Much cheaper that way and plenty on these forums about how to do it.
I second the starbrite hull cleaner. Today a section had Y10 applied and the rest of the hull was sprayed with Starbrite. The starbrite worked a lot faster and not being a thick goo was easier to spray on and wash off.
Get some Oxyalic acid crystals, about 2 teaspoons and add to a coffee jar of warm water. Did my whole boat last weekend and it looks great now. Didn't bother adding any wall paper paste just applied with a brush. Probably cost me about 50p if that. The temperature does matter but above about 6 degrees appears to be OK.
scroll to the bottom and there is some advice on make your own toilet cleaner... which will presumably do the same job on a hull as harpic, particularly as neither cleaner is aware that your hull is not a toilet.
As mentioned above, I would guess that Oxalic Acid will be as effective as anything else. It got rid of some quite serious staining in my bilges, and I'm sure it will get rid of the yellow stain running below the bilge outlet, along with other outlets in the hull.
Thanks guys - as I need to do the job today I think I'll probably try the Harpic first, if not then I'll see if the chandlery do the startbright yacht cleaner....
I won't be trying to find a pharmacy with Oxalic acid today ... perhaps I'll try that another year...
Right - I can report back that the Swafega left for 20 minutes had no effect whatsoever ... the Harpic wasn't too bad, and the T-Cut worked nicely on the stains below the exhaust ...
The chandlery didn't have any Y10 .... or a prop puller ... so we polished the top sides instead...
Quick supply of Oxalic crystals sent next day if req'd. http://www.agwoodcare.co.uk/gbu0-catshow/oxalic%20acid.html?gclid=CNjV5_uzlZkCFQ48QwodIzIobw
They also have a good section on this site for H&S advice.
I reckon it takes the shine off my painted topsides.
I would recommend a good polish after using it on paint but on GRP gelcoat it takes all stains off in an intant and appears harmless if washed off thoroughly after a few minutes.
Definatly gets rid of the green tinge around the waterline, + any rust/blood(from beating the crew) stains etc.