There were two bits of inspiration that lead to this project. Robert was playing with an ultrasonic welder and touched the large vibrating horn during a weld. it felt like ice, frictionless. He thought, could this work in water? The second bit of inspiration came from a news article that large tankers that transported goods across the ocean emitted the same amount of emissions as 50 million cars. What if the drag of those boats could be reduced by just 1%, that would be like taking 500,000 cars off the road!

What it does

There are ultrasonic transducers on the bottom of the "barge". The idea is that when these transducers are on, they are creating cavitation bubbles along the bottom of the barge. These bubbles destroy the boundary layer of the water flow beneath the boat creating a lower drag on the barge itself.

hopefully, when the ultrasonics are turned on, there will be a perceptible drop in drag as measured buy the spring or load cell.

How we built it

We took apart and repurposed two things. The first was an ultrasonic cleaner. We cut out the plate that the transducers were mounted to and created a "barge" out of this plate. The bottom of the barge could be activated to create the cavitation bubbles.

We also got a kitchen scale and repurposed the load cell in it to measure drag. we don't know actual drag, but we are just looking for a drop in the measurement when the ultrasonics are on.

Other than that, we built the flow tank and used a sump pump in a large tank to feed the flow tank. The scale of the barge and the flow tank are designed to match a full sized barge running at full speed along a body of water.

Challenges we ran into

Well, the tank was harder than we thought to build and get right. Further, one of the wires came off of the ultrasonic sensors as we cut it out of the basin. It was clear that we needed to spread out the flow of water from the pump into the flow tank. Mick 3-d printed a special nozzle for that.

Other than that so far, everything is more about stamina than intellectual challenge.

Also, 1/3 of our team wasn't present for most of it as Robert had to go to Netherlands for work and wasn't available to help.

Measuring Success

How do we know this works or not? We simply need to measure the drag of the boat. We don't have any sort of good way to measure some absolute value of drag, however we will use the kitchen scale to report one value when the ultrasonics are off, and then, hopefully, another lower value (or higher if we are using a weight on the unmodified scale) when they are on. If the drag drops, we have achieved success. At least enough success to pursue this project.


Without a doubt there are safety considerations regarding this project with respect to the flow tank and the simulated barge. The flow tank could completely spill onto the floor. we did the best we could to prevent this, but tired people still make accidents. more importantly the piezo transducers in the model barge operate at hundreds if not thousands of volts. Little current, but lots of voltage. So a tipped boat, or water going in places we didn't want could have significant safety or performance issues. controlled the boat and made sure it was stable before we energized the piezos for a test.

Accomplishments that we're proud of

Mostly actually giving this project a shot. It's a real long shot, our team suffered from having less hands when Robert had to go to Netherlands, but we kept at it. building a flow tank and also building a viable barge that simulates the effect we were looking for were big endeavors.

What we learned

Well we learned an easy way to flood the floor of the maker space.

What's next for USS Hackathoon

Mostly a repeat of the the experiment as a more accurate simulation and a more custom design for the boat with more locations for the ultrasonic transducers for learning about what works and what doesn't work.

Then energy calculations along with drag need to be made to assure ourselves that there is an overall energy reduction. After that, if results still seem promising, a larger scale, propelled barge or boat will be tried, with measurements of output energy of both the ultrasonics and propulsion.

Built With

  • cavitation
  • ultrasonic
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posted an update

After working all night building out the flow table, flow and water speed are slow and have some issues with eddy's. The plumbing completed and pvc welded and nozzle was 3d Printed. A boat was also 3d Printed for show

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