Ferrocement hull covered in Epoxy and glass
- Thread starter Wansworth
- Start date
Rappey
Well-Known Member
After reading through the comments on youtube im still clueless as to why they would do this. That led me on to another video where another boat had lots of bubbling. The guy thought it was due to boat being filled, faired and painted while the hull was still damp. The reality is more likely to be lime in the sand which causes bubbling under the paint. Sand for a ferro boat has to be lime free for this reason.
All the epoxy just came away with a chisel, suggesting it has problems adhering to a ferro hull.
With the amount of fairing compound on the hull, that would suggest poor build quality in the first place.
A properly built boat would not need any fairing compound and would never need a grp coating.
Another guy who fibreglassed his hull had it sand blasted. This is a huge No...and was probably the reason he then had to fibreglass it.
All the epoxy just came away with a chisel, suggesting it has problems adhering to a ferro hull.
With the amount of fairing compound on the hull, that would suggest poor build quality in the first place.
A properly built boat would not need any fairing compound and would never need a grp coating.
Another guy who fibreglassed his hull had it sand blasted. This is a huge No...and was probably the reason he then had to fibreglass it.
LittleSister
Well-Known Member
Just why?
A properly built ferro hull doesn't need reinforcement. It is actually reinforced concrete! The steel framing provides the reinforcement.
If the steel framing is inadequate, or isn't adequately protected and is rusting away inside then the hull is a liability - just scrap that is difficult and expensive to get rid of.
I can't imagine that a GRP skin would be strong enough to provide any significant reinforcement of the hull. Does anyone 'reinforce' lintels, bridges, etc. with a GRP skin?
A good ferro hull is great - I've sailed many miles and had lots of wonderful adventures in a friend's ferro boat - but unless the fabrication of the hull was properly documented and photographed - ideally by a surveyor - or you witnessed it yourself, you have no idea how good or bad it is. There are some beautiful professionally built ferro boats, but many were built by amateurs on a tight budget. Some are absolutely fine, but some are dangerous horrors. A lot of the construction time and effort is just tedious donkey work, and easily done by a gang of amateur newbies, but the reinforcement has absolutely to be designed and built right, and the application and fairing of the hull is best done by skilled plasterers.
A properly built ferro hull doesn't need reinforcement. It is actually reinforced concrete! The steel framing provides the reinforcement.
If the steel framing is inadequate, or isn't adequately protected and is rusting away inside then the hull is a liability - just scrap that is difficult and expensive to get rid of.
I can't imagine that a GRP skin would be strong enough to provide any significant reinforcement of the hull. Does anyone 'reinforce' lintels, bridges, etc. with a GRP skin?
A good ferro hull is great - I've sailed many miles and had lots of wonderful adventures in a friend's ferro boat - but unless the fabrication of the hull was properly documented and photographed - ideally by a surveyor - or you witnessed it yourself, you have no idea how good or bad it is. There are some beautiful professionally built ferro boats, but many were built by amateurs on a tight budget. Some are absolutely fine, but some are dangerous horrors. A lot of the construction time and effort is just tedious donkey work, and easily done by a gang of amateur newbies, but the reinforcement has absolutely to be designed and built right, and the application and fairing of the hull is best done by skilled plasterers.
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Rappey
Well-Known Member
I was going to suggest that concrete is not the correct term for a ferro boat but after a quick google it says "Concrete is a composite material composed of aggregate bonded together with a fluid cement that cures to a solid over time" so it would seem it could be called concrete? I thought ballast would be needed for concrete.
Its very fine washed sand and sulphate resisting cement mixed at a 1:1 ratio.
I would say the armature for the boat needs a lot of skill as it needs to be absolutely true and fair. The plasterer will finish the exterior with ⅛" thick plaster coating covering the outer layer of mesh so the plaster will follow the steel, dips and all.
A well built ferro hull will outlast any other hull material . The diy disasters have mostly sunk or are rotting away in the corner of a field so nowadays if a ferro boat looks good its highly likely it is.
They are also very recyclable !
Its very fine washed sand and sulphate resisting cement mixed at a 1:1 ratio.
I would say the armature for the boat needs a lot of skill as it needs to be absolutely true and fair. The plasterer will finish the exterior with ⅛" thick plaster coating covering the outer layer of mesh so the plaster will follow the steel, dips and all.
A well built ferro hull will outlast any other hull material . The diy disasters have mostly sunk or are rotting away in the corner of a field so nowadays if a ferro boat looks good its highly likely it is.
They are also very recyclable !
DownWest
Well-Known Member
Friend built a Ferro 34ft heavy ketch way back. Hull was about 3/4" thick. Lots of steel and he had it plastered by professionals. Very fair, looked like GRP. Huge amount of work getting the armature ready for the plastering. Then had to keep it damp for quite a while to ensure the curing.
Just down the road in Royan, they built an interesting modernistic church, way back. Part of the reconstruction of the town after it had been bombed to ruins by the Allies due to a cock up.
But, they used beach sand and that has come back to haunt them, as it corroded the steel reinforcement....
No idea why anybody would wast quite a lot of money on coating a ferro hull with epoxy/glass.
They extended the lives of quite a lot of commercial wooden fishing boats in the US by ferro coating them. But that is another story...
Just down the road in Royan, they built an interesting modernistic church, way back. Part of the reconstruction of the town after it had been bombed to ruins by the Allies due to a cock up.
But, they used beach sand and that has come back to haunt them, as it corroded the steel reinforcement....
No idea why anybody would wast quite a lot of money on coating a ferro hull with epoxy/glass.
They extended the lives of quite a lot of commercial wooden fishing boats in the US by ferro coating them. But that is another story...
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Wansworth
Well-Known Member
I knew one who sheathed his old Boston shell fishdredger……successful completed with wooden interior,he sailed all over the world…..1975/6 at that time ferrocement was going strong on the east coast.
