Slow raft power/thrust/energy requirements

Boats, Jet Skis, Kayaks etc., including hovercrafts
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stormdot5
1 mW
1 mW
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Joined: Jun 08, 2016 7:05 pm

Slow raft power/thrust/energy requirements

Post by stormdot5 » Jul 21, 2016 10:29 am

I need some help in determining the power requirements for a slightly different water vehicle.
There are some guys at work looking to take part in a homebuilt rafting event.There are about 10 people taking part, with the home built raft (not yet built) probably totaling around 1250-1500kg in weight. As it's not built yet the shape is unknown but it's not likely to be very hydrodynamic. The event will probably take about 2 hours, I'm not sure of the speeds expected but probably walking pace. The craft will be principally human powered but they've been talking about sneaking an electric drive system into the build. It would have to be a cheapo, parts you can find kind of build.

What I'm interested in is whether this would be feasible? They have theorised a paddle steamer style drive and hooking in an electric motor. Seeing as it's expected to be human powered, I assume a similar power output as for electric bicycles, albeit multiplied by the added mass and drag. Although I don't know how to calculate or estimate that drag. Batteries could be old lead acids, without care for their longevity. Everything is likely to be scrapped at the end.

Are there any resources for determining power to weight requirements for this kind of craft at such low speed? From this, energy required and battery weights could be calculated to see if it's reasonable.

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