Winsome is a two person, pedal-powered launch. She's just over 17 feet long and 3 feet wide, and cruises at 4 mph. Her maximum speed is around 7 mph, but that requires unsustainable effort on the part of the crew, whereas you can maintain 4 mph seemingly for hours on end. The two pedal units are 90 degrees out of phase, so that one or other of the crew is always on a power stroke, reducing overall effort and eliminating the need for any kind of fly-wheel. Winsome is designed to achieve her cruising speed on a continuous power input of about 250 watts - 125 watts per person - and the effort required is comparable to cycling on level ground at a wobble-free speed. Cruising in Winsome is less taxing than walking the same distance, and does not inhibit conversation, for example.
The pedals drive the propeller through a custom gearbox with patented lubrication-free nylon crown gears that are virtually silent. The gear box has a 1:2 input output ratio, and the pedal mechanisms offer a further 1:3 to 1:4.5 ratio making a total of between 1:6 and 1:9. To drive Winsome at cruising speed requires a prop speed of between 300 and 350 rpm, so customers can choose between a reasonably fast pedal cadence of 50 rpm or a fairly slow and heavy one of about 35 rpm by their choice of cog. Keen cyclists, for comparison, prefer a cadence of between 80 and 90 rpm, but keen cyclists generally proceed at a brisk and aerobically taxing pace.
Winsome's propeller is 12" in diameter with an 18" "pitch" - the theoretical distance moved by the propeller tip in one complete rotation. The propeller is a resin casting delivering reasonable weight for its manufacturing cost. The propeller - pictured above - is designed for robustness and to shed weed and other debris as far as that is feasible.
The boat is steered using a finger-tip fore and aft tiller mounted under the right hand of the forward facing crew member, connected to a balanced rudder. The boat is extremely manoeuvrable both forwards and when going astern.
Winsome was designed to be transported to, launched on and recovered from rivers, canals, lakes and broads. The adjustable seats, pedal mechanism, gear box and rudder can all be removed from the boat, leaving a bare hull weighing around 55 kg which can be loaded on the roof rack of an estate car. Fully laden she weighs just over 70 kg, and can be wheeled on a canoe trolley along towpaths, around locks and to and from a car park or home.
No comments:
Post a Comment