Ferrocement! Why not?

For sure. I paid £300 for the 28ft ferro hull and spent maybe £2000 on fit out. I lived on it for more than 2 years and sold it to a gaffer enthusiast in Portugal for 1500Euros. I consider that a good return on investment, but most of my boats have been low budget and simple, that can go anywhere, but lack cold beer, washing machines and air-con, that to some people are essential. There is also that "comfort" that if ever there was a "total-loss" scenario, it was more equal to a few months hard work, than years of investment.....I can understand why the latter would want full insurance.

 

Only if it is given the opportunity to. Many modern ferrocement matrices are now coated with epoxy prior to plastering.

 

Nice looking boat! How did she end up with Davy Jones?

 

Thanks for your input! Definitely needs further and updated research.

 

I concur, it was the amateurs that killed the ferrocement industry and pushed the insurance premiums up and made them eventually un-insurable. If it were to be done today and professionally it would have to be done to ISO standards.

 

I've done a moderate amount of concrete finishing, a substantial amount of plastering, and a tremendous amount of woodworking. Wood is easier, and makes a more fair hull. The work to make a fair hull in concrete is way out of proportion for what you get. If I needed a fireproof hull, from my own hands, I'd learn to weld before I'd build in ferrocement, and I already have the skill to do that.

 

The Netherlands are pursuing floating houses using timber superstructure on concrete caissons, tied to dolphins with flexible service connections where necessary:

Waterbuurt - Amsterdam's Floating Neighborhood https://www.odditycentral.com/architecture/waterbuurt-amsterdams-floating-neighborhood.html

Schoonschip: a sustainable floating neighbourhood https://www.metabolic.nl/projects/schoonschip/

 

Presumably those concrete bases are made in moulds by professionals.Some of the most respected hulls in the UK were made of GRP by a concrete building specialist.They got into GRP as a method of producing moulds for concrete that had a high quality surface.Having learned the process they added a GRP hull moulding operation to the business.

 

Those, like many other floating structures are not ferrocement, they are reinforced concrete. There's a whole world of difference between the two.

 

Yes, and I suspect there are very good reasons why the Dutch, who are rather experienced at building water adjacent structures prefer concrete over ferrocement. I imagine there is fibre reinforcement, though I didn't find any sufficiently technical articles in the short time I spent looking. There was reference to a continuous pour to avoid day joints.

 

Yes, I’ll concur with the cold joints being a huge problem with home brew ferrocement.
The only way that I can see the process being completed in timely fashion and without cold joints would be to build in or over a mold, by an experienced team, in which case FRP would be the wiser choice anyway.
Amateur builds I have witnessed seldom proceeded fast enough to keep the reinforcement from rusting ahead of the plastering, so the build was doomed before the plaster was applied.

 

I take it you must have relatively deep pockets then?
One of the main attractions of Ferrocement is the cost of materials.
Building out of wood, regardless of how easy or attractive, it will easily rot in a freshwater environment, yet still it would cost far more than building the same boat out of Steel.
However the cost of steel is going up so even second hand boats are getting expensive, expensive to repair and double-plate where acceptable. I am a 2G in thermal joining skills at best, but I would want to be at least a 4G before I'd even attempt it.
By the time I've factored in my waste and consumables I'd be better off just buying a new steel barge shell off of a yard that builds them production style and start from there.
With regards to fairing a concrete boat I'd just do it as you would steel with epoxy primer and epoxy fairing compound, God knows I've done enough of it, and it'll not suffer the same "starved cow" effect most steel boats show with a bit of age.

 

No, I don't have deep pockets. The cost of the hull is a small part of the whole, and I make enough an hour to know what my labour is worth.

 

I see not reason a wooden boat will easily rot in fresh water. There are boats in fresh water that are over 50 years old and weren't well maintained. As far as cost, a plywood boat is competitive in cost with steel. The cost of tooling is much lower too.

 

If steel plate is going up in price, so is steel reinforcement. If you need to add filler and paint to the mix, the savings aren't going to be substantial. If you need hired labor, any savings are illusory if we compare apples to apples.

The equivalent skill to welding is plastering, the goal is to have a consistent cement thickness, both overall and over the reinforcement. For yacht sized objects we are usually talking 12-35mm total and 1.5mm +/- 0.5mm over the mesh. Fairness is a function of how fair the steel is to begin with, wich is another skill.
There are other systems with more cement over the steel, and wich are more forgiving in this respect, but this only highlights another problem, a lack of modern plans, at least in the western world. I understand China and Vietnam have much more ferro inland watercraft, so I would start there.

In theory you are right, ferro is a very good material for barges and houseboats, but for most people the practical problems mean they can't make any significant savings by using it. Lastly we have the insurance problem, some locations have significant problems with ferro.