First pedal-paddled punt on the Cam

When Trinity Fellow Dr Hugh Hunt advertised the unusual project for Part IIB of the Engineering Tripos, he didn’t expect anyone to take up the challenge – let alone pedal-paddle forth on the Cam this summer.
But one engineering student, in collaboration with Trinity’s puntmen, proved him wrong. Dr Hunt explains:
The idea of a pedal-powered punt was first mooted in 2014 by Trinity Fellow Professor Mike Proctor, now Provost at King’s. His initial idea was a solar-powered punt – or something very eco. After discussing over dinner one night, we decided to put it forward as a final year engineering project in 2015.

I wasn’t expecting any serious takers for this project because it required practical skills with both bikes and boats, as well as some good dexterity with fluid mechanics and Newton’s laws of motion. In Cambridge we often don’t get people like that.

Barnaby Walker proved him wrong. The fourth-year engineering student from Emmanuel was intrigued and set to work to consider how to power the punt, assess the stability of various options and build a balsa-wood model – which he tested in a tub of water in College. Barnaby explained:
It was a great challenge. I was drawn to it as I’ve sailed quite a bit and I’m a very keen cyclist – I rebuild bikes in my spare time.

Inside the mind of an engineer: Barnaby considers the options © Barnaby Walker
Inside the mind of an engineer: Barnaby considers the options © Barnaby Walker

Barnaby worked with Trinity Puntmen Paul Joyce and Ed Few to adapt 28-year-old French Hen to take on board two paddles – like miniature paddle-steamer wheels but instead powered by puff, of a human riding a bicycle.

Cutting holes in the punt went against the grain in more ways than one, says Mr Joyce. The punt doesn’t sink as the paddles are designed to be above the water line.
The biggest challenge was adapting the punt to the new source of propulsion, says Barnaby. It would have been much easier to start from scratch than to modify an existing boat. He said:
The scariest bit was launching it. As always with engineering, you can do all the calculations and modelling beforehand, but when it comes time to actually turn what you have done on paper into reality, there is the sense that you may have missed some crucial detail. But the feeling of relief when it was launched and the punt was a success was a great feeling.
Not only did French Hen pedal-paddle beautifully, her first outing attracted considerable interest – a short video clip has been viewed multiple times. On top of which, the project might well have helped Barnaby secure his first job. In September he starts work at Arup as a structural engineer.

In my interview we talked about it for 15 minutes, they thought it was a very interesting project, given that it combines the mathematical ability, computer modelling skills, and design intuition that are so prevalent in most branches of modern engineering.

For Dr Hunt it underlines the fact that engineering, underpinned by solid maths, embraces creativity, ingenuity and problem solving.
Engineers look at the world as it is and see if it can be made different – and hopefully better! In Cambridge we tend to take ourselves a bit too seriously and sometimes it’s good to let loose on something a bit mad. We’re especially looking to capture the imagination of the next generation of engineers and young people are attracted to nutty ideas like this.
This was great fun but also an excellent challenge. You don’t have to do very serious projects to learn a lot – as Barnaby has proved.

Watch the maiden voyage on the University of Cambridge Facebook page

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