I suggested that reversing a prop would be a cheap way of improving the regen efficency. But just that, a cheap way of proving the concept, as opposed to building a custom regen prop. I any case the taper would have to be machined the other way and the prop would then be ruined if you want to use it in the normal direction.
As others on this list have pointed out before - any gain in regen efficiency will probably be more than offset by the reduction in driven efficiency.
Brown and Marples were trimaran pioneers for many reasons but mainly because a tri could cut the time spent on passage. They liked outboards for power because they were lighter and could be completely raised out of the water and they recommended minimum electrics to reduce weight. Brown would not slow the boat down on purpose.
IMHO: an efficient feathering prop on a trimaran, use LEDs and switch a big power drain like a water pump to manual and you might make up all the power you gain by using regen.
Tom
--- In electricboats@yahoogroups.com, Michael Mccomb <mccomb.michael@...> wrote:
>
> i completely agree that a larger prop will be needed... Â i believe all the boats currently trying to get regen are configured in such a way as to maximize the efficiency of the motored propulsion rather than the regen.... if one reverses that notion because one doesn't care if the propulsion is slower due to an inefficient propulsion oriented prop then fitting out with a prop to maximize regen is possible.... Â i'd be perfectly happy with 5 knots total headway out of a tri as that would give me the ability to get out of a mooring AND sufficient headway to maintain steering control
>
> the larger prop will produce more drag, more regen and will require being turned when not regening in order to maximize the speed under sail.... Â shouldn't take too much juice to turn a prop up to where it is merely no longer producing much drag
>
> i had a fellow suggest that the correct configuration for a regen prop would be a normal highly efficient prop mounted backwards.... Â intuitively this seems correct to me.... Â a well designed and sized Michigan Wheel for instance when mounted backwards would give somewhat crummy forward propulsion but should give great regen..... Â any thoughts on this perspective???
>
>
> ________________________________
> From: "matwete@..." <matwete@...>
> To: electricboats@yahoogroups.com; electricboats@yahoogroups.com
> Sent: Thursday, October 11, 2012 10:00 AM
> Subject: Re: [Electric Boats] regen, displacement, sail plan, hull form....
>
>
> Â
> Regen has been implemented on several boats whose owners are on this list. Â I've not heard anyone talk about getting more than 100 watts or so out at displacement speeds. Â So I think there's a high bar to cross to get even 200 watts, let alone 500watts. Â At most, the prop will see effective water speed that is perhaps 70% of that flowing under the boat. Â At such speeds, you'll need a huge prop to get the power you're looking for.
>
> From my HTC Sensation 4G on T-Mobile. The first nationwide 4G network
>
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