If you are going on a self-propelled river trip, is it really self-propelled if someone takes you back to the starting point when you’re done? Maybe not – and it’s partly for this reason that British entrepreneur Ben Kilner created a convertible paddleboard/bike-trailer combo known as the Duckleberry Finn.
We last heard of Ben in June, when he was pedaling from the navigable source of the Thames to its mouth in the North Sea. He did this in a home-built canoe-like craft called the Jamima Paddleduck, which incorporates an ingenious pedal drivetrain derived from a bicycle he invented.
The main pedals of the aptly named Pedal Paddle system sit on a partial bike frame, mounted in front of the boat seat. A chain drive runs from the crankset of this frame to the crankset of another partial frame at the rear. This has a few paddles mounted on its own set of pedals. Therefore, when Ben pedals in front, the paddles alternately move up and down in the water behind.
An additional hand paddle is used for steering.
The Duckleberry Finn sit-on-top uses the same basic transmission, which is mounted on a wooden frame which is in turn attached to the deck of a 12-foot (3.7m) inflatable paddle board. And although a partial bike frame is still used up front, a full the upside down bike frame is used to spin the paddles on the back.
As long as the device is moving on the water, it remains in the configuration described. Once it reaches the exit, however, the rear frame of the bike is removed from the wooden frame, its pallets are removed and its wheels put back in place, and thus becomes a complete and functional bike.
The rest of the drivetrain is then dismantled, although the wooden frame is then reassembled into a small trailer – the wheels for this trailer and the bike are carried on board while the Duckleberry Finn is in “river mode”. Once the paddle board has been deflated and rolled up, it is placed in the trailer along with various other parts of the system. The bicycle is then used to tow this trailer to the user’s car, home or other location.
Kilner put the Duckleberry Finn through its paces this summer, when he used it to pedal around 161km from the navigable headwaters of the River Wye in the Welsh village of Glasbury, to the final outing on the section tide of the river. in the town of Chepstow. He then converted the craft to its “road mode” configuration of towing a bike and a trailer, and rode it about 80 km to the starting point.
“It was an absolutely magical trip,” he told us. “Probably my favorite adventure so far. The scorching heat with very shallow water after a long drought left lots of pebbles exposed and created rapids where it would normally be quite smooth. The shallow water definitely provided a good proving ground for the niche capabilities of the Pedal Paddle System.”
He added that some improvements still needed to be made. The angle at which the paddles enter the water needs to be changed, for example, and the trailer frame needs to be stiffer. The whole setup also needs to be lightened, as he estimates he currently tips the scales at around 110lbs (50kg).
“To turn it into a boat, it took about an hour and a half,” he said. “With further product development this could be reduced to around 30-45 minutes I think. It took around 2.5 hours to convert it from river mode to road mode and then around another 30 minutes to make it stiffer With more product development, this could be reduced to around 45 minutes.”
With these improvements in mind, Kilner teamed up with “engineering buddies” to produce a manufacturable design and ultimately a commercial product. He informs us that they plan to offer DIY plans, a Pedal Paddle frame that could be adapted for use on third party paddle boards or canoes (river mode only), and a Pedal Paddle Amphibious frame that could be converted into a towed bike trailer.
You can follow his progress and sign up for updates via the Pedal Paddle website – it is also looking for investors, if you are interested.
Kilner’s adventure on the River Wye is documented in the very entertaining video below. If you want to skip straight to the part where the Duckleberry Finn first hits the water, see you at 07:40 – there’s also a good explanation of the setup at 17:57.
“It’s so nice to be able to think of something, create it, and then explore with it,” he said. “It’s a real satisfaction.”
SUP + Bike + Trailer = Amphibious Pedal Paddle | Build and 150 miles of adventure
Project website: Pedal paddle