Modern boat made simple, ferrocement flat sides and bottom and top

[motorbike]

Lots of unsupported statements there. Do you actually have any experience with modern high performance concrete mix design and curing, it are you yet another armchair "expert" whose most recent experience with concrete is the 1970s?

As someone whose read a lot of academic research from the last 25 years or so (i.e. early 90's) concrete design and testing, and implementation, I can tell you that almost nothing that you wrote above is true. You're just furthering misconceptions that, though oft repeated, are no less false and perhaps worse for a forum that purports to be focused on "design", are not backed by even the facile attempt at supporting evidence.

I dont need to have first hand experience, I just look around at the hordes of ferro boats rolling out of the yards. off drawing boards, taking shape in peoples garages. Its overwhelming. The problem you have it that there is theory and practice, and in practice concrete boat construction is simply not economical. The hull is only about 1/3 the cost of a build so do tell how much are you going to save on a ferro cement hull especially with high tech materials? A ferro hull is just that, mostly steel with a thin layer of plaster screeded into a tightly packed armature, moreover to do a top job you'll need skilled labour, a mould to build it over and facilities to steam cure or at least control the environment for a month. Even assuming you'll save 50% over cedar core its still nothing considering resale will whatever you can get for it and dont even ask about insurance. You can beat physics, ferro is heavy and does not come into its own until its in the 50 plus foot 20 ton range, even then why would anyone sink a fortune into a material with such a poor reputation. Ferro has a place, marina pontoons being prime example but for a modern yacht it has had its day.

 

[MikeJohns]

There's concrete and what's termed ferro-cement and they are quite different. Concrete is a great material for pontoons and static barges.

I've had a lot to do with ferro-cement boats and I wouldn't recommend the construction method, it's too weak in shear and a lot of ferro sailboats founder in collisions.

In some parts of the world people are so poor they use left over concrete from building works to make functional but heavy canoes. Necessity being the mother of invention.

 

[rwatson]

Except for that "essentials" canoe illustrated, I cant think of ANY concrete structure, boat or platform, that didn't have steel in it.

That applies to roads, building girders and driveways

 

[MikeJohns]

Except for that "essentials" canoe illustrated, I cant think of ANY concrete structure, boat or platform, that didn't have steel in it.

That applies to roads, building girders and driveways

Even that canoe is steel reinforced concrete looking at the rust bleeds. Probably some left over square mesh !

A more correct name for what we term ferro-cement boat construction would be mortared armature.

The fish farms here have a few old reinforced concrete ammunition barges that were towed here from Sydney. They are used as floating facility "sheds" poured concrete shell and pre-tensioned grouted cables for the global loads.

 

[motorbike]

Well it is the internet, a place where bad ideas come to die. Ferro boats are like the zombie movie where only the element of surprise allows them to eat anyone otherwise its quite easy to hack the zombies to bits as they shuffle and groan their way across the screen.

I miss PAR

 

[tom28571]

Well it is the internet, a place where bad ideas come to die. Ferro boats are like the zombie movie where only the element of surprise allows them to eat anyone otherwise its quite easy to hack the zombies to bits as they shuffle and groan their way across the screen.

I miss PAR

The internet is more often the place where bad ideas come to flourish.

 

[trip the light fandango]

You blokes waxing lyrical on just how bad this medium is don't know much about ferro cement, you probably shouldn't bother commenting, as I shouldn't have just then. it is labour intensive and relatively heavy, cheaper than most and longer lasting done properly,.. ha.. cheers.