Amazing how much of modern inventions originate by learning from nature’s fauna and flora.
Here is an example:
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Now where have I heard that idea before?
Oh yes, I remember…
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The US Coast Guard has also used bubblers to assist with ice breaking on the 140 foot tugs on the Great Lakes. Don’t know if they still do.
They had a small connex box they put on the stern with big compressors in them to hook up to bubblers on the hull. Reports were that it worked well.
I sailed in a frigate that used the AGOUTI system where air was forced through small holes on the propeller to prevent the bubbles collapsing causing cavitation. Owing to the design to incorporate the system the propeller was far nosier if the AGOUTI system was operating at less than optimum.
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Yes the use of air bubbles to reduce friction on icebreakers and other vessels that operate in ice covered waters is not a new thing:
https://share.google/dr0gsOKtud9RtwMr4
For Icebreakers and other vessels designed for operation in heavy ice and low temperature the point is to keep ice from sticking to the hull sides.
For other ships it is to reduce friction, thuse saving fuel and reducing emission from oceangoing vessels.
The use of air bubbles to “lubricate” the hull of ships, both commercial and naval, is also not a novel idea.
My point was where the idea to do so came from, namely from Penguins:
Ah! 
Point taken
Are you aware that my post was on “Penguin Awareness Day”?:
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No, I wasn’t!
Auk-ward!
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Then, of course, the US Navy has had a similar system called Prairie Masker for many years. The system is oriented towards improving survivability against submarine threats by reducing ship machinery and propeller cavitation noise. It injects air bubbles around the hull just below the waterline and then again from the propeller(s).
Don’t you have penguins where you live?
Here in Ålesund awareness of penguin day is every day.
At least at the Atlanterhavsparken aquarium: https://en.atlanterhavsparken.no/
Feeding time for the penguins are especially well attended by locals and tourists:
Favourite with the school children is seeing the penguins gulping down whole herrings, just like the Dutch do it: https://www.youtube.com/watch?v=y5O0J5Q2MfM
Hope nobody gets their knickers in a twist over this being a bit OT.
PS:There are many ways bubbles have, are and can be used, other than lubricating ships underwater body to decrease friction, fuel consumption and emission.
One way is to keep fish captive, or to keep wild fish, seals and otters from getting too close to floating pens used in aquaculture.
BTW: this technique is copied from whales.
On CGC Naugatuck in 1973, went to Toledo dry dock to have installed. They had to add a perforated plate to the ice breaking hull to make it work. Very large compressor installed. was fun to watch when it was activated, not clear on the effectiveness.
Coming back to the original theme of friction reduction with bubbles as a lesson from nature (penguins), I was reminded recently of another “boundary layer” optimisation.
In 1987 America’s Cup, The US entry driven by “the Dennis” (Conner, that is) used a hull finish of “riblets” resulting from NASA research. These were intended to create micro-vortices which reduced boundary layer friction, but also created some controvery too.
Inspired by dolphin & shark skin!
HISTORY - Riblets
20020087761.pdf
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I INVENTED THIS CONCEPT ABOUT 20 YEARS AGO!
test test
[From OP article “… penguins release small bubbles…”]
Releasing large bubbles in your own bath does not count!
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Myth Busters proved the concept and increased the scale by putting a golf ball style divot skin on a full sized automobile and did air resistance testing. Turns out it helps. They also did an episode where they generated a bunch of bubbles under a small boat and got it to sink due to loss of buoyancy. Wouldn’t the little bubbles generated in one of the ship schemes necessarily cause the draft to increase?
Did the small boat move at any speed when they did this?
Nope, just floating stationary.
In the past, I have seen many Sat-C SafetyNet warnings for submarine volcanic gassing expressing this risk.
And large methane leaks under semi-sub rigs I believe.
Be wary people, only fools rush in. Use of this concept on shipping, commercial and naval, would need exhaustive trials to evaluate effectiveness. Reducing underway friction on an immersed hull would compromise the existing technology offered by both self-polishing antifoulings and the far more advanced fouling-release coatings. Both of these systems rely on friction, the miniscule gap between hull and the water rushing by known as laminar flow aside, to keep the underwater hull clean, thereby conserving bunkers and operating cost. Both systems provide zero protection when the vessel is idle, alongside or at anchor but once she’s making way again, protection resumes.
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