Boat Moves Without an Engine Or Sails

coondoggie writes "Researchers say technology they have developed would let boats or small aquatic robots glide through the water without the need for an engine, sails or paddles. A University of Pittsburgh research team has designed a propulsion system that uses the natural surface tension that is present on the water's surface and an electric pulse to move the boat or robot, researchers said. The Pitt system has no moving parts and the low-energy electrode that emits the pulse could be powered by batteries, radio waves, or solar power, researchers said in a statement."

primary school chemistry, anyone?

[arth1]

We made boats that moved by weakening the surface tension back in primary school.
Stick a piece of soap on the stern of a paper "boat", and it is propelled forward.

However, I can't see how the surface tension would be strong enough to drive a full sized boat at any speed. At best you're talking about a few millimetres elevation difference between the bow and stern, if the water is very salty and there's absolutely no wind or currents causing waves.

does not scale

[Anonymous Coward]

So this works if yo are a 2 cm boat (that just wants to spin, apparently) or an insect.

Lots of things that work great for insects don't scale up well. That's why you only see insects using them. Pretty boring. You'll never see thing on a large boat.

for real

[hottoh]

The challenge is going to be scaling the technology from a "2cm" boat to something useful.

It is fairly obvious how a bug moves about on the surface of still water, but the article says boats or small aquatic objects. A boat requires a lot of power to move against waves, wind and ocean currents.

Am I alone in imagining water surface tension is never going to be enough to overcome the resistances to the forces found on our oceans?

little slow?

[Tree131]

So, at 14.4 meters/h, this is only useful for bodies of still water.
Looking forward to improvements in speed, 'cause I think ocean currents move faster than that.

Re:for real

[roguetrick]

Now I might not be one of dem scientist types as such, but I reckon that a boat that uses surface tension for propulsion wouldn't be too much of a submersible.

Re:Calm water

[TapeCutter]

Good question. Many moons ago I worked the fishing boats in Bass Straight. Can it drive a semi-submerged fishing trawler 30 feet up at about a 15-20deg incline, or would gravity drag it backwards?

Re:little slow?

[eggnoglatte]

Right. And speeding up horse carriages is just a matter of how many horses you use. Not.

The fundamental power source here is gravity, by using the difference in elevation of the water surface with low surface tension at the back of the boat and normal surface tension in front. That elevation difference is tiny, and the power it can provide is therefore fundamentally limited.

Re:Is it the Red October?

[pato101]

If I recall correctly, surface tension forces only count to steady state (low velocity motions). Thus, this thing (the story one) only will work at moderate speeds (look at the video: there are no waves in the surface because of the low velocity motion, also means high efficiency). What you propose would generate strong motions, which would kill the tension surface forces.

Re:Boat moves without engine, paddles or sails

[radtea]

commonly known as 'drifting'

It's also false in the case at hand. The boat doesn't have a screw propeller but it does have an engine, which is electro-magnetic and acts on surface tension. This is like saying an electric car doesn't have an engine. Catchy, misleading and perfect for a /. headline.

Re:Calm water

[MightyYar]

No, no, feed them. It's fun to watch the racists all going ape-shit right now.

Re:The rime of the ancient mariner (Iron Maiden)

[scottblascocomposer]

Man, this is why we need a "+1 Awesome" mod option!