Concrete submarine

[waterchopper]

Does anyone here know what happened with the 200 ton concrete submarine that was being built in Columbia? Is there a link to pictures of the boat being built or was there a problem.
Tx Bill

[Guillermo]

This one?
http://imulead.com/tolimared/concretesubmarine/
"Handover scheduled for 14.October 2008 in San Francisco."

There are some threads in these forums about 'concrete submarines'. Designer/builder was a frequent contributor. Just search for them.

Cheers.

[Tug]

I wonder if you put a 100 ft telescopic aluminuim mast/snorkel on it if you could sail a sub while submerged...hmmm..
Cheers
Tug

[daiquiri]

Well, now that I think of it... If I had to design something that needs to get to the sea bottom, concrete would definitely be a material of first choice.

[waterchopper]

I read everything at the concrete submarine site but it seems like all post ended after he recieved the funds to begin building the 200 ton sub for the man in california. I am hoping that he is just busy building or testing the sub and that there was not a problem. He should be completing and delivering the submarine next month some time acording to his last posts in september of 2007. I have tried to search for info on this build but have found nothing.
Tx Bill

[blackdaisies]

You would probably have a water ballast system in it, and empty it to raise it to sea level, raise your mast and sail like that. I've seen cheap plywood designs for underwater boats, but none with a mast on top for sailing above or below the water. That would be interesting.

[Dane Allen]

I've read a lot about submarines from Columbia, and they aren't carrying concrete. Thinking about concrete submaries reminds me of what happens to and egg when cracked under pressure.

I can just picture the brochure now..."It's a submarine, a reef AND a tomb all packaged into one!!!"

[Arildo]

Hmm, iterresting.
Most problem with a submarine is to get it heavy enough vs volume to -actually- dive! I went a different way when I designed and are currently bulding my sub. - Got the volume down!
My sub that is currently under building, has a volume of about 330 litre. It is made of carbon fibre - has ambient pressure (no structural force) and weight about 120kg dry. Then add a pilot (80kg), 100kg in water ballast, and some lead ballast... -and sunk! It has one electric motor each side with rudders and invidual motor control.
If interrested, I can send pictures

[Arildo]

Dane Allen: An egg crack at about 20m depth (according to mythbusters!)

[Arildo]

Columbian concrete sub: Where is the propulution props?

[marshmat]

As strange as it sounds, concrete is (from an engineering standpoint) a very good material for submerged, ambient-pressure structures.

Weight constraints in a sub are minimal; most need a lot of ballast added to dive. And in a 1-atmosphere craft, the vessel is at lower pressure than its surroundings, thus the loads on the shell tend to be compressive. Ideal for reinforced concrete. Indeed, many oil rigs have 1-atmosphere air pressure hundreds of feet down inside hollow concrete legs. A sub is no different- just not as highly loaded, so easier to engineer. And concrete is a hell of a lot easier to form into foot-thick, compound-curvature walls than steel is.

There was a fair bit of discussion about c-subs a year or two ago on here.... looks like the guy is actually building a few now?

[rwatson]

Where is he building a few marshmat? I bet the 200 ton model never makes it into regular use, if it is ever even launched.

I agree that as a stand alone object, concrete is suitable for submerged operation.

As a submarine - no way. The big problem is the "add ons". You cant drill concrete and add reliable thru hulls, structural items etc easily like you can in steel or alloy. Imagine incorporating the anchor hardware and controls, power drives, navigation aids, ballast outlets etc. Sure, you can use epoxy to make it watertight, but the difficualties of the engineering are substantial - eg load bearing valves for ballast thru hulls. Just engineering the entrance hatches and keeping them watertight would be a major drama. Steel and concrete have different expansion rates for a start.

Like all craft, the cost of a hull is a small percentage of the total. The reason for building in concrete is just some lame ass idea for saving money, a relatively small amount of money. You then have to abandon 200 years of engineering knowledge the fart around with crazy, and now dangerous workarounds for essential services. You also have to use the crazy "egg shape" to maximise pressure resistance, which brings a whole lot of other usage problems ( like major rocking at anchor for a start)

Then there is the quality control. Concrete used as subamarine has to be hand laid - every critical inch of it. Ferroconcrete yacht hulls have enough problems - but would you trust your life to high pressures, year after year, knowing that the hull integrity depended on carefull laying every square foot being free of voids, mis-mixtures, etc? You would be dripping sweat on every dive! especially after the first 6 months when you have no way of knowing if the steel reinforcement was being affected by salt conditions.

Finally, it cant be cheap to build such a big sub - show me the broker who will insure the sucker ? So you have 3/4 of a million dollars of floating pavement at the mercy of the elements. Try sleeping soundly at night.

I am all for amatuer sub building-but why start with such a crazy material for the sake of a few dollars. I would love to see pictures of your sub Arildo.

[Arildo]

I'll get pictures 4U rwatson! Not sure if I should get it for everyone, as this is only a prototype.. First do look at the old not updated: www.scubatron.com, but this pics is pretty old......send me an email at "arild.olsen@lifi.no" for more resent picts if of interrest!

[FAST FRED]

I wonder if you put a 100 ft telescopic aluminuim mast/snorkel on it if you could sail a sub while submerged...

A box kite or one of the newer style chute systems would do fine .

No reason to go deep, just far enough to only pay for hull surface resistance , but not wavemaking.

FF

[dccd]

Here is a previous concept of a sailing semi sunken sub ...

http://www.boatdesign.net/forums/sho...0&postcount=71