Small brown blobs that I think are (maybe) alive grow under the roof and in darkish places in the boat. When you touch them they exude watery stuff.



When I know what they are I can them get rid of them for good. They were there before the roof was painted, but have cone back!

Would assume a slime mold or fungus of some type - but there will be an expert on this forum who will advise.

sailingbritican.com/boat-mold-removal/

inspectapedia.com/mold/Brown_Hairy_Mold.php

www.quirkyscience.com/stemonitis-chocolate-brown-slime-mold/

Does the boat have adequate through ventilation from a dorade vent or 2, and a hatch board exhaust vent?

www.boatus.com/magazine/2016/december/preventing-mold-and-mildew.asp

www.concrobium.com/en-au/

What did you paint the deck head (roof) with?

Is it balsa core underneath?

Before I cleaned up all the leaks on my Balsa core deck, I used to get seepage like this, but now the have gone away.
A

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r13 said..
Would assume a slime mold or fungus of some type - but there will be an expert on this forum who will advise.

sailingbritican.com/boat-mold-removal/

inspectapedia.com/mold/Brown_Hairy_Mold.php

www.quirkyscience.com/stemonitis-chocolate-brown-slime-mold/

Does the boat have adequate through ventilation from a dorade vent or 2, and a hatch board exhaust vent?

www.boatus.com/magazine/2016/december/preventing-mold-and-mildew.asp

www.concrobium.com/en-au/

What did you paint the deck head (roof) with?

it doesn't seem to be any of those above unfortunately.
I'll ty borax, vinegar, and bleach to see if one of them works. I printed the ceiling with bathroom, laundry and kitchen paint. there's no flow through venting unfortunately.

Select to expand quote

Andrew68 said..
Before I cleaned up all the leaks on my Balsa core deck, I used to get seepage like this, but now the have gone away.
A

I think it's kit balsa core. The boat is a Holland 25.

I had something similar in one section of my MB21 cabin. It was coincindently around the same area where the deck had developed a bit of flex/sponginess...not severe, just noticeable. It was almost like a resin seeping through. It didn't seem 'organic' to me. I just scrub it off and it seems to go away for quite a while.

Re-seal all your deck gear to start.
Sound like water in the balsa wants to come out and moisture equals mould.

Thanks for the responses everyone