[hpv-boats] converting pedal power to prop power right angles

[v garza]

Don't know what you mean by autonomously, is it large enough for living 
quarters like the old microship projects.

Here's some old links that might be interesting along the same lines:

http://microship.com/microship/index.html

http://www.prophish.com/nyrio.html

Hope this helps.

Vic
----- Original Message ----- 
From: "Brad Larsen" <blarsenb at seanet.com>
To: "'Human Powered Vehicles -- Boats'" <hpv-boats at bikelist.org>
Sent: Sunday, March 20, 2011 12:02 PM
Subject: Re: [hpv-boats] converting pedal power to prop power right angles


>I haven't been active on this list for years but recently got mixed up in 
>an
> effort to build a boat that will go around the world autonomously.
>
> I remember figures on human wattage from this list along with other useful
> numbers.  Can anyone recall the average sustained wattage and peak wattage
> for a human?
>
>
>
> Brad Larsen
>
>
> -----Original Message-----
> From: hpv-boats-bounces+blarsenb=seanet.com at bikelist.org
> [mailto:hpv-boats-bounces+blarsenb=seanet.com at bikelist.org] On Behalf Of
> Giuseppe Carignani
> Sent: Tuesday, March 15, 2011 12:40 AM
> To: Human Powered Vehicles -- Boats
> Subject: Re: [hpv-boats] converting pedal power to prop power right angles
>
> Thanks Rick
> your report is highly informative and seems very accurate, as usual.
> I'm just wondering about Mark Drela's flex shaft propulsion system, the 
> one
> he donated to The Open Waterbike Project
>
> http://www.openwaterbike.com/components/drive-units/mark-drela-drive-system
>
> <http://www.openwaterbike.com/components/drive-units/mark-drela-drive-system
>>The
> shaft is olid but pretty thin (just 3 mm !); nonetheless he says it was
> builit and worked very well.
> Do your calculations confirm this?
>
> As you know I believe the availability of a commercial flex-shaft 
> propulsion
> system could be the turning point in marketable high performance pedal
> boats, so I'm really looking foward to this!
>
> Best
> Giuseppe
>
> Giuseppe Carignani
> Founder, The Open Waterbike Project
>
> On Mon, Mar 14, 2011 at 11:23 PM, Rick Willoughby
> <rickwill at bigpond.net.au>wrote:
>
>> A while ago I decided to do a dynamic model of the crank drive and curved
>> shaft system for a pedal boat.  This was so I could determine how a drive
>> would feel before it was made rather than doing it by trial and error.
>>
>> The model is able to produce time based data on the important parameters
> of
>> a drive system.
>>
>> This trace shows what my current 8mm curved shaft does with a 1:4 ratio 
>> on
>> V14 hull:
>> http://www.rickwill.bigpondhosting.com/Boat_Shaft_1to4%20_solid.pdf
>> From a feel perspective the black curve is the most important.  The 
>> closer
>> it is to a straight line the better.  At 3m/s average boat speed the 
>> crank
>> speed is varying between 60 and 80 rpm.
>>
>> This is the trace with Mark's flex shaft:
>> http://www.rickwill.bigpondhosting.com/Boat_Shaft_1to4%20_flex.pdf
>> For the average boat speed of 3m/s the crank speed is going from slight
>> reversal up to 140rpm.  With 170mm cranks 140rpm corresponds with my
> maximum
>> foot velocity so that was my speed limit with the flex shaft.  I have
> video
>> that shows the stop-start nature of the pedaling so the model is
> reasonably
>> close to reality.
>>
>> I have also modeled what the flex shaft would be like with a 1:8 ratio
>> driving a 12X12 prop:
>> http://www.rickwill.bigpondhosting.com/Boat_Shaft_1to8%20_flex.pdf
>> Here the crank speed variation is from 40rpm to 120rpm.  This would feel
>> tolerable and I could get slightly faster than 3m/s before hitting my
> 140rpm
>> limit.
>>
>> So with higher gear ratio the flex shaft system looks to be an economic
>> means of getting a right angle drive and mounting the prop within reach
>> beside the hull.
>>
>> Also with practice at spinning, the crank speed would be smoother.  Even
>> with the 1:4 ratio I could hold quite steady foot speed with the flex
> shaft
>> up to about 8kph. I do not have enough training to "spin" as I load up.
>>
>> The dynamics depends on the boat and prop as well as the shaft and gear
>> ratio.  If anyone wants a shaft system modeled in this way it does not
> take
>> long to do.
>>
>>
>> Rick Willoughby
>>
>>
>>
>>
>> --
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