Personal Submarine Cruises SF Bay

LandSonar writes "Graham Hawkes, the guru of the submarine design business, tried out his new submersible sea plane yesterday in SF Bay. Called the 'Deep Flight Aviator'. Article and cool pictures. This craft doesn't use ballast like traditional subs. Flys more like a plane. 'It looks like something NASA might build or the Blue Angels might fly.'"

Comments

No Ballast?

[zer0vector]

If the submarine doesn't use ballast to maintain its depth, it must always be in motion to stay at a depth away from equilibrium. Assuming it is positively bouyant (it floats) the motion of the water over its dive planes would be the only force holding it underwater. This seems a bit limited to me, since you'd never be able to stop and enjoy the view underwater. It's probably because I'd be more interested in the stuff sitting on the bottom of the ocean, rather than the things moving through it, which appears to be the point of the sub.

Re:No Ballast?

[neksys]

The article states that, when the submersible drops beneath "stall" speed (approx 1.2 knots), a conventional ballast system kicks in to maintain dive depth - making it perhaps more versatile than conventional submersibles, as opposed to the limitations that you suggest.

More cool Small Submarines

[TheLurker]

For more cool homebuilt submarines, check out the Personal Submersables web page.

Re:Plans?

[Reality Master 101]

Yeah! I even got a name for you: how about "The Suicide Express"? "The Widowmaker" is already so overused.

build your own sub

[paughsw]

This team at Virginia Tech, (I used to be on it) are the three time world champs for a human powered submarine. Check them out, lots of cool videos, and documentation. www.hps.vt.edu

Re:Extreme high pressure...

[RoundTop-VJAS]

well... the flight principle would work at those depths. Assuming the parts can stand the pressure (what they are trying to get done). even though the pressure has changed, the resistance of the water will be essencially unchanged. (since the propellers will be biting more in the water, producing more thrust, this will ofset any drag problems). Since it is designed to cut through the water rather than force its way through (conventional sub) it should work.

The problems at 39k feet are following:

#1) materials that can stand up to it. I'm sure that a piece of solid metal can, but can the cockpit? #2) If anything goes wrong...ANYTHING. you are dead. #3) Making sure your seals can stand the pressure (any that rupture - see 1 & 2)

However if the cockpit can sustain the pressures (since it is smaller than a full regular sub it should be able to take more pressure.) then it should be able to hit those depths no problem. Not only that, but at the proposed dive/accent speeds they might have to worry about the bends. at 400ft/min to go 37,000ft would only take 1.5h. All the "modern" subs/deep subs take much longer than that to hit those depths ('cept some military ones...but they don't go as deep [as far as we know])

This concept has actually been around for a while, however I give massive kudos to these guys for pulling it off not once, but twice. I watched the documentary on discovery about Deep Flight and that was cool. DF Aviator is definately a step in the right direction as it gets rid of the classic sub image.

As for increasing the speed for more than 6knots.. that is a simple equation.

Running time = battery power / draw of props (increases as revs go higher)

So either increase the battery capacity (for the same weight) and speed for the same running time. Or you will sacrifice run time.

Eg: To make it go ~12knots it would take roughly twice the battery power, reducing its effective time from 8h to 4h (I know there are more things..but that is the major factor).

Another technique is to increase the size of the props. But that takes more energy to get them spinning (for more thrust though).

How long til these are outlawed?

[Anonymous Coward]

A cheap, small, personal submarine, capable of carring two people--or one person and 200lbs of drugs from Mexico or Canada into the U.S.A. (or 200lbs of explosive, or ...)

Watch the U.S. Coast Guard build lots of sonar installations. Watch the ecologists sue the Coast Guard for what all that sonar does to the sea life.

Watch Congress outlaw personal submarines.

Re:Extreme high pressure...

[BLAG-blast]

I'll try and dispell some myths for you rather than just calling you dumb.

Since it is designed to cut through the water rather than force its way through (conventional sub) it should work.

There is no difference between how this submarine moves through the water and how a "conventional sub" would move through the water.

Making sure your seals can stand the pressure

Any rubber seals are just for the first few feet. After 30 feet the water pressure will be creating a metal to metal bond (or metal to acrylic or what ever) so the seals will not do anything. If you're refering to the metal to metal bond as a seal, then you kind of right, but any problems would have notice at around 30 feet. As you go deeper the bond will just get stronger.

Not only that, but at the proposed dive/accent speeds they might have to worry about the bends.

The bends only apply if you are exposed to outside pressure. This is a 1 ATM sub, you are always at the same pressure as you where on the surface.

Eg: To make it go ~12knots it would take roughly twice the battery power, reducing its effective time from 8h to 4h (I know there are more things..but that is the major factor). Another technique is to increase the size of the props. But that takes more energy to get them spinning (for more thrust though).

This isn't really true either, it would probably be more like a quarter of the endurance for twice the speed. But they might be other things limiting the speed such as drag, the sub isn't a very hydrodynamic shape and might have a low terminal velocity.