A slightly damper project

David Martin said:

A small boat such as a canoe, a few bike bits,
some fibreglass and a prop.. how hard can it be?

sounds easy! Finished it yet? You've got an hour before "My name is
Earl" is on ...

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 is the idea. Still in the back of an
envelope stage and thinking about how best to put things together.

A small boat such as a canoe, a few bike bits, some fibreglass and a
prop.. how hard can it be?

Just buy a pedalo. It's a recumbent pedal powered waterborne vehicle.
If you want speed, it will have to be long and narrow like a sculling shell
but these are unstable so you will need some outrigger floats. You could put
a couple of paddlewheels between the main hull and the floats, directly driven
from the pedals, and the shaft will be out of the water so no problems sealing it.
I think I've just designed your first racing boat for you.

You could also try an inboard impeller like a jetski or an external prop but you
would have problems turning the drive through 90 degrees and sealing the shaft.

--
Eiron

No good deed ever goes unpunished.

On 26 May 2006 11:56:10 -0700,

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 is the idea.

You mean a pedalo - I can understand why there were tortured screams <g>

--
Andy Leighton => [email hidden]
"The Lord is my shepherd, but we still lost the sheep dog trials"
- Robert Rankin, _They Came And Ate Us_

Eiron 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 is the idea. Still in the back of an
envelope stage and thinking about how best to put things together.

A small boat such as a canoe, a few bike bits, some fibreglass and a
prop.. how hard can it be?

Just buy a pedalo.

Noooo! Not a pedalo.

Quoted message said:

It's a recumbent pedal powered waterborne vehicle.

So, it isn't what I have in mind.

Quoted message said:

If you want speed, it will have to be long and narrow like a sculling shell
but these are unstable so you will need some outrigger floats. You could put
a couple of paddlewheels between the main hull and the floats, directly driven
from the pedals,

Not paddle wheels. A screw is more efficient. An impeller jetski style
might also be possible (the impeller could be mounted sideways.)

Quoted message said:

and the shaft will be out of the water so no problems sealing it.
I think I've just designed your first racing boat for you.

You could also try an inboard impeller like a jetski or an external prop but you
would have problems turning the drive through 90 degrees and sealing the shaft.

Sealing the shaft is not a problem (ie it doesn't necessarily need to
be sealed) It is the 90degree bit that could be harder to make
reasonably efficient.

...d

David Martin said:

A small boat such as a canoe, a few bike bits, some fibreglass and a
prop..

This is typical of what is wrong with this country. You're thinking too
small. Think big! Build a Trireme with 200 stationary bikes for slaves
to pedal. If the Greeks had invented the bicycle chain they'd have done
it. Legs can provide much more power than arms, and the chains &
associated drives can stop the blades from clashing. No need for
overseers with whips to keep time -- big cost saving!

So you say slavery is illegal in this country? So is crossing a red
traffic light. Put the traffic light cameras to work and everyone on
bike or in a car who crosses a red light gets 24 hours pedalling the
Trireme! No shortage of slaves then ;-)

Thinks: must petition the Parish Council to get the stream widened to
accomodate Triremes.....

Mike

"David Martin" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message 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 is the idea. Still in the back of an
envelope stage and thinking about how best to put things together.

A small boat such as a canoe, a few bike bits, some fibreglass and a
prop.. how hard can it be?

..d

I've been thinking of doing this for years. I'm building a bigger boat at
the moment, but I have discovered a whole world of HPBs. Here are some
sites.
http://www.humanpoweredboats.com/
http://openwatercycling.com/features.htm
http://microship.com/bobstuart/spinfin.html
http://bikerdave.murioi.com/

Do let us know of progress.

Mike Sales

Eiron said:

You could also try an inboard impeller like a jetski or an external prop
but you
would have problems turning the drive through 90 degrees

You forwardfacingseatingist, you.

R.

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? Diving planes would of course work better at higher
speeds *cough*electricassist*cough*, and there is the problem of making
it all watertight (although, how about some sort of magnetic coupling on
the propshaft, through the watertight skin?). Early models might want
to use a SCUBA tank for oxygen, mind.

R.

Richard 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? Diving planes would of course work better at higher
R.

90 degree drives, seals??????

Pah!

Have a look at http://www.aquaskipper.com/.
(From the links already posted, thanks)

Richard said:

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

It's already been done! See:
http://www.atomiczombie.com/gallery/bradgraham/ubike.htm

David. Most pedal power prop drives achieve the 90 degree change of
rotation with a twisted chain, although some use crown gears.

I intended to use the gearbox from a dead angle-grinder when I built my
boat, but then someone offered me a commercial drive unit:
http://boatpage.xntrick.co.uk/

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? Diving planes would of course work better at higher
speeds *cough*electricassist*cough*, and there is the problem of making
it all watertight (although, how about some sort of magnetic coupling on
the propshaft, through the watertight skin?). Early models might want
to use a SCUBA tank for oxygen, mind.

That's what the existing human powered submarine competitions do.
(And what several small powered commercial and diy kit subs do.)

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.

Quoted message said:

Richard said:

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

It's already been done! See:
http://www.atomiczombie.com/gallery/bradgraham/ubike.htm

I'm not really after a submarine. Hopefully I'm looking for somethign
that can manage to make way against the currents in the Tay.

Quoted message said:

David. Most pedal power prop drives achieve the 90 degree change of
rotation with a twisted chain, although some use crown gears.

That is something worth thinking about. I was thinking of a long drive
shaft to put the prop at the rear of the boat. Not sure how long a
chain I will need to avoiud too much strain if it is twisted

Quoted message said:

I intended to use the gearbox from a dead angle-grinder when I built my
boat, but then someone offered me a commercial drive unit:

Unfortunately it was the right angle gear box that killed my last dead
angle grinder. Though at the cost of a few pints of beer it is almost
worth buying one just to use as a RA gearbox.

I think I will be looking for a surfski or similar as the base hull,
though a colleague has a topper...

...d

In article said:

Richard said:

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

It's already been done! See:
http://www.atomiczombie.com/gallery/bradgraham/ubike.htm

Also e.g. http://www.isrsubrace.org/
http://www.oceanlight.com/lightbox.php?ss=human_sub

Quoted message said:

David. Most pedal power prop drives achieve the 90 degree change of
rotation with a twisted chain, although some use crown gears.

I intended to use the gearbox from a dead angle-grinder when I built my
boat, but then someone offered me a commercial drive unit:
http://boatpage.xntrick.co.uk/

http://microship.com/bobstuart/spinfin.html is a similar drive unit.

Quoted message said:

Have a look at http://www.aquaskipper.com/.
(From the links already posted, thanks)

I've looked but I still can't believe it!
Such a pity I can't be both cycling and canoeing this afternoon.

--
Eiron

No good deed ever goes unpunished.

in message <[email hidden]>, David

Martin (') said:

Quoted message said:

Richard said:

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

It's already been done! See:
http://www.atomiczombie.com/gallery/bradgraham/ubike.htm

I'm not really after a submarine. Hopefully I'm looking for somethign
that can manage to make way against the currents in the Tay.

Doubtful. If the tides in the Tay are anything like the tides in the
Solway you'll get peak flows in the order of six knots. You'll need a
vessel at least sixteen feet long on the waterline to achieve that at
displacement speed. You'll also need an exceptionally easily driven hull
shape for a single pedaller to be able to sustain that speed for any
length of time.

Quoted message said:

I think I will be looking for a surfski or similar as the base hull,
though a colleague has a topper...

Both of those are hulls designed to plane. You don't have enough power to
do that. You need something like a competitive rowing boat - very long,
slender and smooth.

--
[email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/
Ye hypocrites! are these your pranks? To murder men and give God thanks?
Desist, for shame! Proceed no further: God won't accept your thanks for
murther
-- Robert Burns, 'Thanksgiving For a National Victory'

Simon Brooke said:

in message <[email hidden]>, David
Martin ([email hidden]'😉 wrote:

Quoted message said:

Quoted message said:

I'm not really after a submarine. Hopefully I'm looking for somethign
that can manage to make way against the currents in the Tay.

Doubtful. If the tides in the Tay are anything like the tides in the
Solway you'll get peak flows in the order of six knots.

No, that's just the normal river current. Current + ebb tide and the
shape of the Estuary can give ten knots at Broughty Ferry. Obviously
using the

Quoted message said:

You'll need a
vessel at least sixteen feet long on the waterline to achieve that at
displacement speed. You'll also need an exceptionally easily driven hull
shape for a single pedaller to be able to sustain that speed for any
length of time.

Quoted message said:

Quoted message said:

I think I will be looking for a surfski or similar as the base hull,
though a colleague has a topper...

Both of those are hulls designed to plane. You don't have enough power to
do that. You need something like a competitive rowing boat - very long,
slender and smooth.

http://www.humanpoweredboats.com/Photos/HydrofoilHPBs/HydrofoilHPBs.htm
gives some idea that you may not be correct in this..

...d

in message <[email hidden]>, David

Martin (') said:

Simon Brooke said:

in message <[email hidden]>,
David Martin ([email hidden]'😉 wrote:

Quoted message said:

Quoted message said:

Quoted message said:

I think I will be looking for a surfski or similar as the base hull,
though a colleague has a topper...

Both of those are hulls designed to plane. You don't have enough power
to do that. You need something like a competitive rowing boat - very
long, slender and smooth.

http://www.humanpoweredboats.com/Photos/HydrofoilHPBs/HydrofoilHPBs.htm
gives some idea that you may not be correct in this..

It doesn't, you know. All those boats share two things in common:

(i) They're hydrofoil lifted;
(ii) They have very long, fine hulls (just like I said) in order that a
pedaller can pedal them up to a speed at which the hydrofoil lift will
work.

There will be an inevitable hump in the power curve needed to get up onto
the foils. Once up, the power needed will drop (or else you'll go
substantially faster for the same power input) because the drag will
drop sharply once the hull is clear of the water. But until you're up,
hull + foils is a lot draggier than hull alone, so you need to get the
hull drag down to an absolute minimum.

--
[email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/

;; no eternal reward will forgive us now for wasting the dawn.
;; Jim Morrison

Simon Brooke said:

David Martin (') said:

Simon Brooke said:

David Martin ([email hidden]'😉 wrote:

Quoted message said:

Quoted message said:

> I think I will be looking for a surfski or similar as the base hull,
> though a colleague has a topper...

Both of those are hulls designed to plane. You don't have enough power
to do that. You need something like a competitive rowing boat - very
long, slender and smooth.

http://www.humanpoweredboats.com/Photos/HydrofoilHPBs/HydrofoilHPBs.htm
gives some idea that you may not be correct in this..

It doesn't, you know. All those boats share two things in common:
(i) They're hydrofoil lifted;
(ii) They have very long, fine hulls (just like I said) in order that a
pedaller can pedal them up to a speed at which the hydrofoil lift will
work.

There will be an inevitable hump in the power curve needed to get up onto
the foils.

There's the trampofoil alternative of start off fast enough to use foils
and sink if you don't maintain it, but I wouldn't seriously consider it
for tidal waters.

Simon Brooke said:

in message <[email hidden]>, David

Martin (') said:

Simon Brooke said:

in message <[email hidden]>,
David Martin ([email hidden]'😉 wrote:

Quoted message said:

Quoted message said:

> I think I will be looking for a surfski or similar as the base hull,
> though a colleague has a topper...

Both of those are hulls designed to plane. You don't have enough power
to do that. You need something like a competitive rowing boat - very
long, slender and smooth.

http://www.humanpoweredboats.com/Photos/HydrofoilHPBs/HydrofoilHPBs.htm
gives some idea that you may not be correct in this..

It doesn't, you know. All those boats share two things in common:

(i) They're hydrofoil lifted;
(ii) They have very long, fine hulls (just like I said) in order that a
pedaller can pedal them up to a speed at which the hydrofoil lift will
work.

There will be an inevitable hump in the power curve needed to get up onto
the foils. Once up, the power needed will drop (or else you'll go
substantially faster for the same power input) because the drag will
drop sharply once the hull is clear of the water. But until you're up,
hull + foils is a lot draggier than hull alone, so you need to get the
hull drag down to an absolute minimum.

There weer abunch of other boats mentioned in other links in this
thread which are claimed to be eminently capable of maintaining a good
speed without hydrofoils. I'd expect some of those to be planing as
well. You (as you well know) do not need much speed for planing, just a
good hull design.

It'll be fun playing around anyway, and will be limited by what I can
find. Anyone have a scrap sea kayak lying around?

...d