Darpa and its super fast/super loud subs...100 knots

A while back someone posted some info about super cavitation and torpedos mentioned.. Since it is new to me I thought it may be new to others

www.darpa.mil...

From Defensetech.org >>
A SUPER FAST, (SUPER LOUD) MINISUB

The Day (New London, CT) on Monday had an intriguing article about DARPA's Underwater Express. This program aims to prove engineering approaches for a manned minisub able to carry high value cargoes submerged at 100 knots -- a "super-fast submerged transport," or SST. Underwater Express was announced with a request for proposals in 2005. The RFP specified supercavitation, a form of enhanced submerged propulsion exploiting a self-made vacuum cavity or gas envelope between hull and ocean to reduce flow resistance by "60 - 70%." Supercavitation, such as used in the Soviet-Russian Shkval rocket torpedo, is extremely noisy. Even allowing for a breakthrough in how the gas cavity is created and maintained, the classic power-versus-speed formula makes it highly likely that only a rocket engine could achieve the required 100-knot speed for the SST. Yet the RFP mentioned nothing about silencing the technology demonstrator minisub.

After a competition, General Dynamics Electric Boat was awarded a contract which by completion is expected to total $38 million. The deliverable will be a quarter-scale unmanned version of its winning design, to be demonstrated in the waters off New England in spring 2010. The demo is to include runs at up to 100 knots for 10 minutes, with maneuvers to show that the SST is safe at such speeds. GDEB says they've solved the challenges of maintaining a stable gas envelope while accurately controlling the test vessel's depth, course, angle of attack, and speed. Details are top secret.

I'd been wondering what good there might be to a manned minisub that, unlike a rocket torpedo, has to be reusable and survivable -- but which would, whenever moving fast, make a huge passive sonar signature, broadcasting its presence to any enemies for miles around. Besides, what missions would it be used for that couldn't be done by a HALO insertion and Osprey extraction, or for that matter by a slow moving battery-powered mini like some Improved ASDS? When The Day's article came out, I decided to ask a source. The rest of this is my interpretation of the answers I got, sprinkled with public info and my own conjectures and commentary.

Continue reading "A SUPER FAST, (SUPER LOUD) MINISUB"

www.defensetech.org...

Maybe they are testing a torpedo under a different codename.

reply to post by BlackProjects


First link does not work...

As for the SST i guess my self its largelly impractical but evolution of things always has to start off somewhere.
What lyies behind it if such is another story

It sounds like it is a good project but for a civilian purpose, anything other than that or a torpedo. Or for a false positive.
I cant think of another military use because the whole ocean will know of their position.

it wont matter who hears it, what are they going to do about it, it will be faster than any steerable torpedo, and faster tha just about ant thing on the water.
and anything that can go that fast on the surface would never be able to track it through there own noise.
Also the places it will be used they wont know what it is, it will sound like a speed boat.

The original article says it will used to deliver high value cargoe, what ever that may be.
I suspect the first application will be something like a high speed under water landing craft to insert a squad of troops very quickly.
It will herald the begining of a new era of underwater warfare, one where ultra silence wont be the end all be all.
If the demonstrator works, then expect to a whole host of new types of under water vehicles.
About 10-12 years ago i read a fascinating article on a naval engineering groups concept for underwater "flying" vehicles. Vehicles that would perform in much the same manner as an airplane, at under water speeds approaching 200mph. At that time the only thing holding them back was a suitable power plant.
A couple of years later i read another very good article of super cavitating projectiles/vehicles, two things of note was the mention of a sea water/powdered aluminum fueled turbine or rocket.
Essentially sea water is injected into a "swirl chamber" at high velocities, it is mixed with the powder aluminum, and an extremely exothermic reaction takes place creating super hi temp steam and aluminum oxide as an exhaust.
The steam is at temps like 800 degrees or something.
The high pressure steam cam be used to drive a turbine to turn a shaft or an electric generator or it can be just exhausted much like a rocket motor.
The steam can also be used to generate the gas envelope.
Just think about the possibilities of squadrons of under water fighters, shooting super cavitating projectiles from under water cannons.
Or inserting squads of troops onto a beach or into a port with almost no time to react.
researchers have fired super cavitating projectiles from an underwater cannon at muzzle velocities approching 1200'/sec, thats damm fast underwater.

along the lines rapid insertions
The marines are looking at orbital insertions of squads of marines anywhere in the world in two hrs.