ferro-cement???

[Wardy]

I can understand the attributes of GRP, a nice resiny waterproof substance that is strong yet has some bendability; Steel, very strong, water impermeable, and can also bend but might leave a dent; But Ferro-cement, it rings of a non waterproof material that when shocked will shatter, not the sort of thing you'd want on a yacht.
However, I know it is used, so what process makes it suitable for floating craft? Are there any downsides? And why are ferro boats usually cheaper than their counterparts? Unless, of course, it's because they are brittle and sink easily!

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[Talbot]

There have been some very good ferro boats, but attitudes are somewhat biased against them in UK because of a lot of very poor lay-ups done by amateurs. If done properly they will last for years, Some of the barges constructed for the normandy temporary harbour are still afloat, and these were made of ferro.

As you say, they dont take shock particularly well, but will take abrasion better than GRP especially on coral.

Because of the attitude in UK, a good ferro can be had for a lot less than the equivalent made in another material. Some people would say that there is no such thing as a good ferro boat, but if you can find one that was professionally constructed to a high standard and have a surveyor who understands ferro, there are good savings to be made, provided you are thinking a long term solution.

Not suitable for a short term solution because of the grief in trying to sell

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[Althorne]

We know all about ferro boats don't we Talbot???????

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[snowleopard]

the common assumption is that it's a concrete boat. in fact it's a steel boat with mortar used to keep out the water. a pure concrete boat would be just as useless as a polyester boat without the glass reinforcement - it would simply shatter.

the aim of good ferro boatbuilding is to get as much steel as possible into the hull which makes it pretty strong.

they are cheap to build because the raw material is cheap, though labour costs are high compared to GRP. they are cheap to buy because the material has a bad reputation - in the UK, less so down under. badly built examples can hardly be given away.

a few points about pros and cons of ferro:
suitable only for heavy displacement
easily repaired after major hull damage
less strong than steel/aluminium in contact with coral but better than grp


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[Talbot]

no comment!

you still want to come down for a sail?

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[silverseal]

Over 5000 barges were made out of ferrocement, during WW2 to ferry grain from Canada to the UK. Sixty years later, they are still around, and still in excellent condition. A few years ago we tried to sink one to make a harbour, and I can tell you that we worked very hard to make a hole in the bottom. All down to how well the original boat was laid up - very much like GRP, except perhaps no osmosis?

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[boatmike]

A good boatbuilding material let down by too many poor amateur jobs.

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[Bergman]

As someone said the strength is in the steel "reinforcement" within the concrete shell.

The difficult bit is when this starts to corrode.

Difficult to detect in early stages and tends to be beyond economic repair when it is detected.

Hence the low prices and difficult sale

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[stokes]

Google "Wear concrete tugs" one built in 1919, still lies on a bend of the river to this day. It was stripped out and beached in the 194tes

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