Sail, Kayak or Pedal: Three Boats in One

We love self-propelled carbon free transport, but who is going to complain if there is a little wind at your back. We also like using leg power as well as arms, which is a problem in canoes or Kayaks. Hobie solved this problem with its Mirage Drive, which converts a stepping motion into dual flipper action that is surprisingly strong, easily winning a tug of war with a tandem kayak. "Your feet rest naturally on the pedals and you pedal effortlessly similar to a bicycle. The larger muscles in our legs produce more powerful propulsion versus arms using a paddle."

Throw in a paddle and you have a full body workout. Add the outriggers and a sail as in the Adventure Island model and you can go just about anywhere. Its all rotomoulded plastic, but light, long lasting and cheap. Unlike the Tu-fin, the recumbent position means a low, stable centre of gravity, and it is in production. Maybe if I can convince Hobie Alter that I am a long lost relative he will give me a discount. ::Hobie Adventure Island

from the Hobie website:

Even we were surprised at the efficiency of the MirageDrive. In a test to compare the efficiency of the MirageDrive, we measured the heart rates of several kayakers at varying speeds in several paddled kayak models. In every case, the heart rate-or effort expended to maintain a particular speed-was three to ten percent less for pedaling versus paddling. Translation? The MirageDrive converts the effort of the human body into forward thrust more efficiently than a paddle! Allow us to explain.

The MirageDrive creates less turbulence in water. This becomes apparent when you compare the wake of a Hobie Mirage to the wake of a paddled kayak. With each stroke of the paddle, you'll see two vortices, or whirlpools, on the surface of the water. These vortices are connected underwater, and there is considerable energy in these rotating masses of water. There are vortices in the wake of the MirageDrive, but since the MirageDrive acts on a much larger volume of water, they are much smaller and therefore contain less energy. To create forward thrust on the water, a boat must move water backward. It can either move a little water quickly, or a lot of water slowly. The key to efficiency is to move a lot of water slowly with the least amount of turbulence. The volume of water that the MirageDrive acts upon is approximately proportionate to the area that the fins sweep in one cycle, or about 226 square inches. The volume of water that a paddle acts upon depends on the type of stroke. A basic stroke would act upon a volume of water proportionate to the area of the paddle, or about 90 square inches. This is just a fraction of the area "swept out" by the MirageDrive, which explains the difference in efficiency.

Tags: Boats

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