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Student-designed system could transmit data and power through submarine hulls

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March 9, 2011

Tristan Lawry's ultrasonic system is theoretically able to transmit data and power through...

Tristan Lawry's ultrasonic system is theoretically able to transmit data and power through submarine hulls (Image: RPI)

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Given the deepwater working conditions endured by submarines, one of the last things most people would want to do is drill holes through their hulls. That's exactly what is necessary, however, to allow power and data to flow to and from audio and other sensors mounted on the exterior of the vessels. Not only do these holes present a leakage risk, but they also diminish the hull's structural integrity, and the submarine must be hoisted into drydock in order for any new sensors to be added. Now, a doctoral student at New York's Rensselaer Polytechnic Institute (RPI) has come up with a method of using ultrasound to transmit power and data wirelessly through a sub's thick metal hull – no holes required.

The system, created by RPI Electrical, Computer, and Systems Engineering student Tristan Lawry, utilizes piezoelectric transducers to convert electrical signals into acoustic signals and vice versa. Power and data are relayed via separate non-interfering ultrasonic channels. Conventional electromagnetic wireless technology, by contrast, is thwarted by the shielding effect of metal hulls.

Tristan Lawry's ultrasonic system is theoretically able to transmit data and power through...

In lab tests, Lawry has simultaneously and continuously transmitted 50 watts of power and 12.4 megabytes per second of data through a 2.5-inch-thick (63.5 mm) solid steel block in real time. These numbers are reportedly far better than those attained in previous attempts at ultrasonic data and power transmission through metal, thanks to the digital technology utilized. The tests are also said to mark the first time that high levels of power and data have been transmitted through metal simultaneously.

Lawry believes that with minor tweaking, his system could handle even higher data rates and power levels. He stated that the thickness of the metal is not a significant challenge, nor are imperfections on its surface such as rust, or imperfectly-mounted transducers.

Besides its use on submarines, Lawry believes his system could also ultimately be utilized in nuclear reactors, chemical processing equipment, oil drilling equipment and pipelines, armored vehicles, or space shuttles and satellites.

About the Author
Ben Coxworth An experienced freelance writer, videographer and television producer, Ben's interest in all forms of innovation is particularly fanatical when it comes to human-powered transportation, film-making gear, environmentally-friendly technologies and anything that's designed to go underwater. He lives in Edmonton, Alberta, where he spends a lot of time going over the handlebars of his mountain bike, hanging out in off-leash parks, and wishing the Pacific Ocean wasn't so far away.   All articles by Ben Coxworth
7 Comments

Brilliant, unless an enemy sub is listening for your "ultrasound power signature", in which case you're dead meat. And by the time you realize you're there, they already know YOU'RE there.

Ike Rai
9th March, 2011 @ 11:31 am PST

I was wondering the same as Ike Rai, I am assuming that as a submarine was chosen for the technology it is designed for either research subs / DSV 's or they have a solution, which being military we of course won't find out about.

Hmm_OK
9th March, 2011 @ 08:35 pm PST

I was thinking the same too, but being of higher frequency than the normal mechanical vibrations that designers try to design out of their subs, do ultrasonic waves travel very far in sea water anyway?

mokkybear54
10th March, 2011 @ 01:18 am PST

Saltwater has a very high absorption rate needing low frequencies to allow long distance transmission: Think long wave radio or whale song. The faster the frequency, the more it is absorbed.

The Hawaii Institute of Marine Biology clocked a Dolphin's echolocation detection of Atlantic Cod as between 22 and 173 meters depending on species.

Dolphins generate an average 55khz ultrasound pulses. Practical ultrasound energy transmission that I am aware of is in the 600-1000khz range which is more than an order of magnitude higher in frequency. Absorption rates would drastically diminish the range at those frequencies, and by orders of magnitude as well.

Add that to a hull that's wrapped in sound dampening material, techniques that reduce the sound further, other techniques to produce seemingly random "sounds", and my guess is the detection range is less than other existing emissions and noises coming from the ship.

Caveat: I'm no expert, am just as fascinated by the story, your mileage may vary and you may experience different rates of weight loss/gain by reading any comments I make.

Kynth
10th March, 2011 @ 06:21 am PST

Ultrasounds are just what whales use to communicate with (we can hear just a little with our ears of their singing), so yes ultrasound travels famously in water! But the idea to not make holes in the hulls is not that bad, but subs without holes can mot excist, can they?!

I mean how to get the crew onboard, otherwise?!

I think a glass port hole through which micro-waves are beamed will be more practical, not least if more power than 50W is needed - which kind of add-on would do with just 50W power - hardly a sonar, nor mechanical devices!

Tord S Eriksson
10th March, 2011 @ 06:43 am PST

Stuinning! What the mind of man can accomplish is amazing!

Nick Lucko
10th March, 2011 @ 06:45 am PST

What a great idea. You can't imagine how many Hull Penetrations there are on a modern submarine, there are thousands. If this technology could be used just for the low power applications it would probably cut the number in half. Think of the savings in construction time and testing. Every hull penetration has to be x-rayed and pressure tested to beyond test depth and then paperwork on each is created and stored. The real cost is in the paper.

There are a lot of systems that will still require a penetration to pass fluid, gas or mechanical actuators (although actuators are being minimized) through the hull. Hatches for people, loading and weapons will continue to be required, but they are stronger than the hull by design, so not really an issue.

This would be a huge increase in hull integrity and a big savings in construction and maintenance costs.

As to the transmission of noise into the water, I should think that most would be absorbed by the hull and transducers, I'm pretty sure the remainder could be shielded or isolated from the water.

David G. Cole
10th March, 2011 @ 01:28 pm PST
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