Maybe we are not nuts getting more popular

[overlander]

Check this out from Bionx.

SeaScape Watercraft | pedel powered personal watercraft | Powered by BionX

 

[Ultra Motor]

Wow! This looks great!

 

[z0mb13e]

Yup - that looks like fun. Would be great for bimbiling around poole harbour - though for some reason I thought it would be faster.

I guess it is probably out of my price range - will have to stick to the kayaks.

As for the iphone dock/app. Half of me loves the idea that all these new devices are getting interfaced with smartphones but half of me curses the fact that they are all apple based. I guess it will take manufacturers a while to catch up with the rising tide that is Android...

 

[flecc]

Would be great for bimbiling around poole harbour - though for some reason I thought it would be faster.

Boat speed with displacement hulls is related to length, so at around 12' that 5 knots is about the limit.

The only ways to go faster is to have a planing hull skimming on top of the water driven by very high power, or a longer hull. That's why large ocean liners can do 35 to 40 knots using moderate power, they are long enough.

Technically the limitation is the bow wave, this creates a following trough that the boat drops into, a short hull readily dropping into the trough and speed dragged down. Marine engineering, fascinating variations from road vehicle technicalities.
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[z0mb13e]

Well you really do learn something new every day!

 

[EdBike]

Interesting, but it'll never really catch on. Who owns a pedalo anyway?!

As soon as you're trying to move water out the way rather than air, you need to much more power. I don't think batteries are the answer the that...

 

[flecc]

As soon as you're trying to move water out the way rather than air, you need to much more power. I don't think batteries are the answer the that...

Not really Ed, see my reply above, only moderate power is needed to achieve water displacement maximum speed for a given hull length. Any attempt at using power to displace the water above that speed results in digging a bigger hole in the water to fall into, plus cavitation bringing risk of destroying the propeller blades.

This is why larger expensive motor boats have hulls flattish bottomed at the rear, the extra power lifting them on top of the water to plane across the surface rather than attempt to push the water out of the way. When achieving breakout speed to planing the acceleration is very sudden. My own small 17 footer would only achieve 5 knots maximum displacement using moderate power, but opening the throttle to maximum lifted it out when it would skim at nearly 30 knots. The latter really eats the juice though!
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[z0mb13e]

Would an electric motor not be more suited to use in an impeller?