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Jim Baerg


Regarding the ancient rowers "They didn't have the sliding seat of today's competitive rowers". I recall reading a few years ago (unfortunately I don't recall where) that they might have had something equivalent. Depictions of galley rowers show them with a cushion tied to their buttocks & it is thought the bottom of the cushion was greased to allow it to slide & let the rower use their legs to do most of the work. It might have been a contributing factor to the Greek victory at Salamis.

Jim Baerg


"It is important to realise that pedal powered machines (and bicycles) require fossil fuels."

I don't think that pessimistic statement is justified. (I say pessimistic because in the long run even the most frugal use of fossil fuels will use them up faster than they are created, so if the statement was true there would eventually be no steel for pedals.) However, charcoal from biomass was used to reduce iron ore to metalic iron for millenia, though on a smaller scale than we have been doing with coke made from coal. If necessary we can use the steel in the petroleum fueled vehicles to make a few billion pedal powered machines & since you say they last for a century, the steel production needed to replace 1% of those machines per year would likely be small enough to be done with charcoal from wood.

Also is there any reason iron ore or rust couldn't be reduced to metal using electricity or hydrogen split from water using non-fossil energy? (Aside from coal being cheaper for now.) Steel production would be done near large hydroelectric plants in sparsely populated areas the way aluminum is done now.



I do wonder, if certain hardwoods are strong enough to take up to a certain threshold of human mechanical pedal power, such that you don't need steel or other such things at all in the end?

Ok, it may take plantations, and time, but that could be done sustainably.

Where there's a will, I think there's always a way!

christina brine


I thought you might enjoy this weblink... 507 Mechanical Movements... some of the illustrations are animated. http://507movements.com/



While the axles have to be thicker and the roller bearings far larger there is no reason to think you can not build peddle powered equipment out of hardwood. A carefully knotted rope could work in place of a chain for power transfer without the efficiency loss of belt drives.



If necessary we can use the steel in the petroleum fueled vehicles to make a few billion pedal powered machines

Vibeke Bjornlund


Does anyone know of a pedal powered chaff cutter? and if it can cut 1 inch branches

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