Cleaning lichens off gelcoat?

[Philip.AK]

I have a boat that has been sitting on a rack for a while uncovered, and there are lichens growing on the gelcoat. I need to clean them off, and I thought I'd start with a non-toxic spray of white vinegar with a bit of dish soap as is suggested online. Or I could just go at it with a brush. What have folks here found to be the best method for the gelcoat?

TIA

 

[Doug_Lloyd]

Sounds about right with the vinegar. I dunno, you have to have a mechanical release first from the porous gelcoat on a GRP hull. That’s probably a chemical and elbow grease. I know a few friends with canoes left idle far too long and it’s always the same issues, though their can be some serious residue staining. I’ve used Goof-off and Magic-eraser at times for the final cleaning before polishing with whatever people like. I’m not sure if power washing is a good idea on a smooth surface. I suppose you can control the force. Too much is never good for the finish. Of course the best maintenance is preventative maintenance but you aren’t here for a lecture

 

[CPS]

I usually use a bit of Palmolive and a deck brush. Some gelcoat is softer so a gentler touch may be required.

 

[Philip.AK]

I sprayed it down with a mix of vinegar and a dab of liquid dishwashing soap. I’ll let it sit for 24 hours and then use a brush with some sudsy water. It was a warm day so the vinegar and soap mix probably dried relatively quickly, but the soap helps it stick. This soap-vinegar mix I have actually used successfully as weed killer. It’s kind of dumb that it ended up this way, because I actually had a fabric cover for the boat and I just didn’t bother throwing over until it was way too late.

 

[Philip.AK]

I don’t know if the 24 hours of vinegar solution made any difference, but today I used a medium-bristled scrub brush and soapy water (plus some elbow grease) and went to work on the boat. The lichens came off reasonably easily, though some ‘roots‘ seemed to remain, but I got those with a ‘non-scratching scouring pad’ (does that concept compute?). Anyway, a pretty easy cleanup.

 

[SalishSeaNior]

You could also use a marine cut wax with a variable speed buffer and pads if you one. That will take the discoloured gel coat surface down a bit to refurbish the finish. Well worth the cost if you want to spruce up the boat, or if you have more than one to maintain. I use my buffer to take out minor scratches on the deck from wear and tear and paddle blade entries every spring. Works very well.