The main reason why "personal submarine" projects fail 95% of the time is due to the enormous costs of forming thick plates of steel into the desired hull-shape.

So why not use some other material alltogether? Why not use concrete for example? concrete's been used for a very long time in the construction of tunnels. Hey, if it can withstand the force of a lake plus 10 or 20 meters of rock, sand and rubble, it could be used as a submarine hull too.

I'm thinking about a neutral buoyancy type submarine, with a steel frame encased in 50cm thick concrete. True, it would not be able to dive to the extreme depths metal-hulled subs are able to reach, but then again, who would want to go there?

The best place for recreational submarining would be depths where sunlight can still penetrate. A maximum depth of 50 meters would be more than enough.
-- akumabito, Nov 10 2005

Concrete Canoes http://members.cox....oe/introduction.htm
Civil engineers have an annual concrete canoe competition. They probably have many of the technical issues worked out for you. [Worldgineer, Nov 10 2005]

Pumpkin Boat Race http://zed.cbc.ca/g...82448&c=contentPage
Carved out pumpkins as boats. [Zimmy, Nov 10 2005]

Concrete Ships http://www.ferroboats.com/
...in general are a well-established industry. [DrCurry, Nov 10 2005]

Concrete Submarines http://www.engineerguy.com/comm/3469.htm
"Perhaps the most bizarre application for concrete is in making ships and submarines...A concrete submarine can dive deeper than a metal one because concrete is very strong under pressure." [DrCurry, Nov 10 2005]

Concrete Submarines http://www.popularm...efense/1281166.html
Coming to a jihad near you, according to this 1998 article. [DrCurry, Nov 10 2005]

It may make a difference when the concrete is lined with sheet metal, or rubber-like tiles. Remember those black rubber tiles often found at playgounds?

Or perhaps helicopter-like bars underneath the craft to make it possile to sit on the seabed.

Though I really don't think it would fracure that easily. It takes a LOT to break concrete, especially when it is very thick..
-- akumabito, Nov 10 2005


Papier Mache?
-- Ling, Nov 10 2005


Sounds like a plan to me, although I know nothing of concrete engineering (or much of anything else, really).

P.S. Actually, this technology appears to be pretty well established, or at least widely discussed, although I can't find any pictures of actual concrete submarines. Possibly this stuff is still secret.
-- DrCurry, Nov 10 2005


Thanks for the links! I never knew they were already experimenting with this! Very interesting!
-- akumabito, Nov 10 2005


Now we'll have to kill you.
-- DrCurry, Nov 10 2005


I love it when ridiculous-sounding ideas turn out to be baked or at least seriously researched.
-- wagster, Nov 10 2005



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