Very Kool Indeed. What are the average speed for average out ? I want one. Whats the mechanical peddle mechanism look like and how does it work?

Todd

--- In harryproa@yahoogroups.com.au, Rick Willoughby <rickwill@...> wrote:
>
> I am applying about 110W in the video clip through a 1:2 gearbox at a
> cadence around 65 so prop is doing maybe 130rpm. The boat is doing
> between 5 and 6kts.
>
> The prop blades are 40mm wide by 4mm thick aluminium flatbar filed
> into a NACA07510 section but mirror of the front edge on the trailing
> edge rather than a tapered trailing edge. As stated before the
> diameter is 540mm and pitch is 1300mm. The blades fold to enable
> coasting and shedding weed. It has very little slip because it is
> such a large swept area. The velocity ratio is only 1.015. You can
> see the blades flashing past in the video.
>
> The mirrored section had no noticeable difference from the previous
> section that was standard NACA16410. The foil data shows that there
> would be some vortex shedding off the trailing edge but I am not
> going to notice that at the gentle speeds I am doing here.
>
> There are pictures of the boat and another clip in rougher weather here:
> http://www.rickwill.bigpondhosting.com/V15.htm
> Aim with this boat was to get the deck at the bow to carve through
> waves without diving. I am happy with the way it works. I would
> probably go for a bit more reserve buoyancy in the ends on a proa hull.
>
> Yes - The rudders are what are referred to as dipping rudders - I
> have used these for a while now as the only drag is when I need to
> turn and they avoid collecting weed. The ones at present are taken
> from another boat. I am going to make simpler blades for this one as
> they work as deflectors rather than proper foils so the foil section
> is a waste and adds unnecessary drag.
>
> Rick