Update: Much has happened since the Tu Fin concept was first published on Yanko Design roughly a year ago. We been presented that they now have a full working prototype and well be showcased at the coming Munich Trade Fair Centre. Congrats to the Tu Fin Team!
Tu Fin is a new sport, operated with body strength boat. At 8 meters long, it offers place for a driver and one passenger. The driver is looking forward while driving the boat. The body movement activates almost all groups of muscles and ensures thereby holistic cycle-strengthening body training. With it Tu Fin connects the advantages of the fitness training with those of the Nordic Walking – a complete body Workout in free nature. The innovative fin drive is inspired from nature for and guarantees maximum acceleration without any noise. Entire Kraft from arms and legs transfers into the fin impact. Together with the flow optimized trunk achieves Tu Fin a maximum efficiency and Speeds up to 6,6 knots. The low tail serves as bath platform,and the front boat part as leisure platform.
Designer: I.Kiryakov, S.Ballmeier, K.Eichelberg & M.Dressler
First prototype of Tu Fin in full operation.

that is going to be highly unstable, you will tip over sideways
I think same way. Why don't make a cat like this it would be stable..
I think same way. Why don’t make a cat like this it would be stable..
looks cool, but I prefer the reclining paddle boats of yesteryear
They already have boats like that with bicycle mechanisms on it. I’ve seen people using them at the lake and they look fun. It looks like you are riding a unicycle but where the wheel should be there is a surfboard!
the flippers seem inefficient for converting fore-aft human body motion. essentially the person is acting like a piston, so a flywheel and propeller is probably more efficient.
That looks fun bet there are more traditional ways to move a boat that involve the whole body.
Take a look at a japanese sculling oar (http://www.woodenboat-digital.com/woodenboat/20060910/?pg=560) with instructions on how to build several types here: http://www.amateurboatbuilding.com/articles/howto/sculling_oar/
These are less complicated and can be built with wood and hand tools. No fancy gearing required. If you insist on machinery Hobie has kayaks with a fin driven drive that you pedal that is proven to be more powerful than paddling. Here’s one that’s installed in a home built boat. http://www.duckworksmagazine.com/03/r/projects/mirage/index.htm
It’s too bad that “Tu Fin” means “Your End” in Spanish. Who wants to buy a product called Your Demise that actually looks like you could die using it?
Oh, Great!! Probably much more fun than bicycle version! This on the water and Segway on the ground! Yeepee! \o/
Looks unstable to me, as well. Add a bit of wind and waves and it will be difficult. BTW, how do you steer this thing?
Anyway, I’d rather go rowing on the street than cycling/stepping on water. 🙂
I think more people like boating than walking on boat.
Is it eco friendly? Interesting sport…Better to walk on it than treadmill. We could enjoy the view.
That’s definately going to be the most unstable boat in the world.