A slightly damper project

Simon Brooke wrote:
you'll get peak flows in the order of six knots. You'll need a

Quoted message said:

vessel at least sixteen feet long on the waterline to achieve that at
displacement speed.

<curious>
How do you connect the two figures?
</curious>

R.

Alan Braggins said:

In article said:

David Martin said:

I am cogitating on the possibility of engendering not only tortured
screams from the garage but also from the boatyard. A recumbent pedal
powered waterborne vehicle

You're thinking too two-dimensionally. How about a recumbent pedal
powered submarine?

Interestingly, it would actually be more efficient to have a relaxed
crew doing no work and breathing less, and use the extra compressed
air in a pneumatic motor instead of using human power.

All needlessly complex:-
What you need are some knobblies.
http://www.thatvideosite.com/view/2471.html

Simon Brooke said:

in message Richard(') said:

<curious>
How do you connect the two figures?
</curious>

Displacement speed in knots is roughly square root of the waterline
length in feet + 2. That's roughly

[...]

Quoted message said:

The displacement trap is about wave-making. [...]

And, just for completeness, the waterline length matters because the speed
of a deep-water wave depends on its wavelength, and the limiting wavelength
of the wave in a boat's wake depends on its waterline length (roughly, you
can't get a longer wave than a crest at the bow and a trough at the stern
other than by planing). http://en.wikipedia.org/wiki/Hull_speed gives more.

Simon Brooke said:

This is why kayaks and rowing skiffs are the shape they are - weight for
weight and payload for payload a long fine hull is more easily driven
than any other, which is why when the limiting factor in your design is
the amount of power you can put in, long fine shapes always win.

Wow, this takes me back to the long thin warship v. the short fat
warship argument of the late '70s, early '80s. A certain shipyard and
supporter of the short fat ship has recently been seen playing with a
trimaran, using three long thin hulls.

So that's settled then.

Al C-F said:

Wow, this takes me back to the long thin warship v. the short fat
warship argument of the late '70s, early '80s. A certain shipyard and
supporter of the short fat ship has recently been seen playing with a
trimaran, using three long thin hulls.

So that's settled then.

The objective as I understand it was stability is severe sea states.

And it was that lot that starts with a backwards iQ that designed it -
the other lot just built it for them ;-)

--
Tony

"Anyone who conducts an argument by appealing to authority is not using
his intelligence; he is just using his memory."
- Leonardo da Vinci