Barge Out of Concrete?

[Hotel Lima]

Hello again,

What would the feasability of a large barge built out of steel reinforced concrete be? We are looking to cut costs on our next build and this would probably be cheaper than steel. How long does concrete last? How does it react with saltwater? Can it withstand an open ocean passage? Does is erode away after a few years riding the waves? I assume you have to seal it and what kind of maintence and upkeep is nessicary to keep it in solid safe order (It's a dumb barge dosn't have to look nice).

They barge would be 280-300' by 60-80' flat bottomed and unpowered.

Thanks for your time,

jake

[alpamis34]

Why to build a concrete boat instead of building it with other vast variety of materials ,especially with contemporary materials like fiberglass,kevlar etc.

Concrete is not a commonly used material compared to others and the risk of coming across with cracks within the hull is truly high after using it in the rough seas due to the slamming.

[MikeJohns]

Actually it has been used extensively and very succesfully for barges and even ships were built of concrete in WW2 by the US and Japan the US ships operated across the atlantic for many trips without any problems.

Iwo Jima still has one of the Japanese ships hard aground and there is a breakwater of US concrete ships still floating in one of the great lakes. They are proving to be very durable indeed.

I have recently surveyed a 100 foot ex-ammunition naval barge. The whole thing was poured reinforced concrete, including the decks. Now it is a moored service vessel for a salmon farm. They are so inert that they can be left for 20 years without any maintenance. Just grow a small reef on the bottom. Think of boat ramps, provided they are a good waterproof vibrated mix with adequate cover over the steel the ramp will last indefinately.

The only way I have seen them cracked is by shipping coming too hard unfendered alongside and then it is spalling rather than cracking of the hull that occurs.

You'll probably need an engineer .

Cheers

[Verytricky]

They are reported to be very very reliable. They can be hit with a 5 pound hammer blow with no ill effect. I know several yachts made this way and sailed around the world!

Two issues: They will deprecate quickly in money value as they are very very difficult to survey: And voids in the makeup of the pouring of the cement or rebar too close to the skin can rust and both flaws are fatal.

I have tones more info if you are interested.

[Crag Cay]

We need to be a little careful here with which construction technique we are considering. Generally yachts are made of 'Ferro-cement', ie an almost woven structure of steel bars and mesh that is then waterproofed by being plastered in cement.

The alternative which I believe Hotel Lima is considering here, is steel reinforced concrete, as used in civil engineering projects. This is a far more massive, robust, big boat, style construction that has, as has already been pointed out, been used successfully on larger vessels.

The Mulberry harbours built for the D-Day invasions were made like this and floated over. The one of them that was assembled correctly on the French coast is still largely intact, 60 years after its design life expectancy.

[safewalrus]

The only problem is, if you ever need too, one of repairs! New concrete can be difficult to bond to old! But other than that there isn't much can go wrong with the stuff - not very pretty true, but it's a dumb barge not a yacht so looks probably won't come into the equation. How ever as Mike Johns sez above you'll need an engineer to fiddle with the mix, work out the stresses and strains etc. you'll have a big expensive brick otherwise. But generally it should do the job, good luck with the build

the Walrus

[yipster]

another concern could be service on the underwatership, if not for a prop, fouling and kelp will grow
long ago i lived on a dutch bark like this in the river amstel
boat was big and old, there and then i learned from some other skippers concrete was often used on the inside to repair a rusted hull
even worse but still in mind was the story used oil is magnetic and heavyer than water so could be used on the hull drooping down the waterline to the keel
here some newer concreet living on water design designs

[l_boyle]

I heard about some college students testing a concrete canoe..
I wondered if it float.. Once it get swamped, well it a bye bye boat...

[marshmat]

Concrete canoe competition is alive and well, as it has been for many years. http://engsoc.queensu.ca/canoe/2006/index.htm for instance, they work out of the same building as I do.

[Hotel Lima]

Do you guys think it would be cheaper to build than steel? That's the main reason why we would be doing this,

jake

[safewalrus]

Cheaper? yes, but by how much? Suppose it depends on what sort of stength you require, like all things! As long as you don't expect miracles I guess it would be a lot cheaper, but again it depends on strength required, area of use etc etc. Needs a lot of research - more than a few lines of forum, but is it worth it? Yeah I reckon so mind you that's just me with no formal qualifications into design etc. just experience. You really need to talk to one odf the designers on the forum - you'll soon find 'em they are they guys who talk numbers! I'm usually shouting at them not to be so bloody technical for us poor grunts! but yeah they know their stuff - especially the ones who shout back. Bloody boring but I got to admit they do know what they are talking about - just don't let them know I said that, they'd love it!

[MikeJohns]

Originally Posted by safewalrus

............. especially the ones who shout back. Bloody boring but I got to admit they do know what they are talking about -.............

Sounds a bit conciliatory for you Mike.


Hotel Lima

If this barge is to be towed around a lot then steel is better by far, but so far you have not given us much of a design brief.

Any more specific advice and you need to tell all (or most at any rate).


Cheers

[l_boyle]

Originally Posted by marshmat

Concrete canoe competition is alive and well, as it has been for many years. http://engsoc.queensu.ca/canoe/2006/index.htm for instance, they work out of the same building as I do.

My goodness, they did it..
Lucky, that they didn't tip the canoe, they never will be able receive it once its sank to the bottom....

[Wynand N]

Originally Posted by l_boyle

My goodness, they did it..
Lucky, that they didn't tip the canoe, they never will be able receive it once its sank to the bottom....

and why not....

[l_boyle]

You would think after watching a stoneware bowl floating in the dishwater, just a tiny ripple cause the bowl take on water and sank to the bottom of sink