Will marine fouling grow on polyurethane sealant?

Ian_Edwards

Ian_Edwards

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Will sikaflex (or similar polyurethane sealants) allow marine growth to grow on it?

Or to ask the question another way do I need to antifoul sikaflex?

Anyone out there with any practical experience of this, and I know this is a big ask, but any photographs of polyurethane sealant which has been in seawater for a season?
 
Ian_Edwards said:
Will sikaflex (or similar polyurethane sealants) allow marine growth to grow on it?

Or to ask the question another way do I need to antifoul sikaflex?

Anyone out there with any practical experience of this, and I know this is a big ask, but any photographs of polyurethane sealant which has been in seawater for a season?
Click to expand...


No photos Ian but this is how you do it. Scuff up your sealant with wet and dry then paint with an alkyd based paint then primocon or similar then anti foul its a faff but it works.

John
 
I'm asking because I'm told by a boat yard that they don't need to antifoul a Sikaflex seal between the grounding plate and the hull on my Southerly.

I fairly sure it does, but I am looking for some back-up/support, just to make sure I'm not asking for something unreasonable.
 
Ian_Edwards said:
I'm asking because I'm told by a boat yard that they don't need to antifoul a Sikaflex seal between the grounding plate and the hull on my Southerly.

I fairly sure it does, but I am looking for some back-up/support, just to make sure I'm not asking for something unreasonable.
Click to expand...

it is rubbish....
 
The official advice from Southerly is:

'Caulking cotton around keel studs then 'Arbokol 1000' around studs and along top of grounding plate.
Gap filler compound between grounding plate and keel box perimeter 'Sikaflex 291i'
 
Surely the width of the sealant will be so thin as to be a non event fouling wise. I would be more concerned about rusting on the edge of the keel plate because that is the edge of the paint to the metal
My keel has rusted along a thin line where it meets the hull & has damaged the coppercoat a little. At this point the metal primer has stopped & not been carried around the edge of the metal.
There is no indication that the sealant has fouling on it as I can hardly see it
Of course the Southerly may have a totally different detail so comment irrelevant
 
Daydream believer said:
Surely the width of the sealant will be so thin as to be a non event fouling wise. I would be more concerned about rusting on the edge of the keel plate because that is the edge of the paint to the metal
My keel has rusted along a thin line where it meets the hull & has damaged the coppercoat a little. At this point the metal primer has stopped & not been carried around the edge of the metal.
There is no indication that the sealant has fouling on it as I can hardly see it
Of course the Southerly may have a totally different detail so comment irrelevant
Click to expand...

It's not thin on a southerly often as much as about an inch. It's not structural like a normal keel the structural bit is higher up the box.
 
Ian_Edwards said:
The official advice from Southerly is:

'Caulking cotton around keel studs then 'Arbokol 1000' around studs and along top of grounding plate.
Gap filler compound between grounding plate and keel box perimeter 'Sikaflex 291i'
Click to expand...

So the sealing is done with a polysulphide and the gap filled with a polyurethane. From what I remember of the way the grounding plate is set into the hull, that seems a very sensible arrangement and can't see why your boatyard is reluctant to follow the builder's recommendations.

Insist!

BTW it won't get much fouling under the hull owing to the lack of light so normal coat of AF will be fine.
 
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