Mechanical engineer Keri Collins from the University of Bath joined us at Bestival to explain why fish – and even turtles – are the best inspiration for submarine design, and how next year she might be the queues to the Isle of Wight in a pedal-powered sub…

Keri-Collins

Biomimetics, also known as bio-inspiration, bionics or biomimicry, is the process of looking at how problems are solved in the natural world and using that information to create solutions to our own technological problems. This isn’t as simple as straightforward copying though – if you strapped a pair of wings to your arms and waved them around, you wouldn’t be able to fly, you’d just get tired. And yet birds have been instrumental in creating our own flying machines, from aeroplanes to helicopters to small flying spy craft, often called micro air vehicles. The key is to isolate the physical principle and apply it in a new context.

At Bestival, I explained to the gathered crowd some of the fish-inspired propulsion projects I have been involved in. Through an audience participation exercise, we explored the many ways in which fishes swim. From Nemo-esque clown fish, rowing with their pectoral fins, to the giant Manta rays, to wiggly eels, each fish has evolved according to its environmental niche. So fish-inspired propulsion has a large pool (no pun intended) to draw from.

There are three projects I’ve been involved in while at university (apart from my actual research) that rely on bio-inspired propulsion. The first was the Gymnobot, a knifefish-inspired small craft.

Keri with fellow mechanical engineer Ryan Ladd and the Gymnobot. Photo courtesy of the University of Bath.

The knifefish is a particularly interesting fish as it can move backwards, forwards, up and down all using just one fin, a “ribbon fin” that runs from the fish’s chin to its tail. This makes the fish, and one day, the Gymnobot when it is finished, very maneuverable.

The second craft was an autonomous underwater vehicle (AUV) built for a robot submarine competition.

Inspired by turtles, this sub can move in any direction – even up and down.

This took its inspiration from the flapping fins of turtles. Since its fins could be flapped about any direction, the AUV could go forwards, backwards, up, down, and turn really quickly “on the spot”.  Unfortunately a flooding incident left our entry incapable of progressing too far in the competition.

The third, and perhaps the most exciting, project is the human-powered submarine. This wasn’t really one of my projects – but I did help drill some bolt-holes so I count it. The sub itself is a couple of metres long; one person climbs into and pedals very hard to operate the propulsion mechanism.  The first time our team entered the International Submarine Races, they designed a biomimetic propulsion system with two fish-inspired flapping fins on each side of the sub.

Fins, inspired by fish. Bolt-holes, drilled by Keri Collins.

The team did very well, finishing second in the one-person, non-propeller speed challenge.

The reason the human-powered sub is the most exciting to me of all the bio-inspired subs: I noticed on the way to the festival there is a “swim to Bestival” event… What if next year we have the first “pedal-your-own-submarine-to Bestival”? If this sounds like your cup of tea, check out the Bath University Racing Submarine Team and get building.

Keri’s event at Bestival was sponsored by the Royal Academy of Engineering.