On Tue, 23 Nov 2010 17:46:50 +0700, Bruce
wrote:

Out of curiosity, why chain the shaft? Are you running on one engine?
And, if you are how is it working for you. I tried it and it simply
dropped the speed by about half :-(

On our boat we can improve fuel efficiency by about 25% running on a
single engine assuming a speed of no more than about 1.1 SQRT LWL.

We have Detroit 6-71 2-cycle diesels which are not efficient at low
speeds. Running single engine gets operating RPMs up to a normal
level. This is useful on long passages in relatively light winds and
calm seas. If the wind kicks up we need more power to maintain speed
and stability.

Joe wrote:

Have been on a hundred boats with 25-72 inch props and had to chain
them down many times to prevent damage to the gears. As I said the
power is massive and you had better have heavy chains and binders.

Joe





There is no doubt that the prop will turn (or at lest want to) when
water flows past it.

But to develop any real power, the pitch of the blades has to change.
Think about it from the POV of the propeller.
When running and moving the boat, the prop attacks the water stream
at a fairly fine angle. Spinning, the prop takes a small bite of
water and sends it aft. Water meets the prop a small angle off of
the leading edge.

When not running, and just dragging through the water, the angle of
attack is huge. Water hits nearly flat on the face of the blades.

If you want to use the prop to generate electricity, to have any
kind of efficiency, and reduce drag, the prop blades need to change
pitch by about 90 degrees.

And all that just to reduce mechanical and speed losses to minimum.
They WILL still be there.


Some people seem to think that since it's a sailboat, and slow anyway,
that a little loss of speed is ok.

I'm of the other mind. Since it's already slow any additional losses
are unacceptable.

(trim yer sails, mate)


--

Richard Lamb
email me:
web site: www.home.earthlink.net/~cavelamb

On Tue, 23 Nov 2010 06:15:07 -0500, Wayne.B
wrote:

On Tue, 23 Nov 2010 17:46:50 +0700, Bruce
wrote:

Out of curiosity, why chain the shaft? Are you running on one engine?
And, if you are how is it working for you. I tried it and it simply
dropped the speed by about half :-(

On our boat we can improve fuel efficiency by about 25% running on a
single engine assuming a speed of no more than about 1.1 SQRT LWL.

We have Detroit 6-71 2-cycle diesels which are not efficient at low
speeds. Running single engine gets operating RPMs up to a normal
level. This is useful on long passages in relatively light winds and
calm seas. If the wind kicks up we need more power to maintain speed
and stability.

I've got littler engines and at cruise are running about 2,000 RPM on
both. Cutting one engine reduces speed by about half.

But you have, I believe a Grand Banks, which has a semi-planeing hull,
I think the company calls it, that can benefit from larger engines. My
boat is a displacement hull so additional H.P. isn't going to make a
vast difference.

You say "maintain speed and stability", do you have active
stabilizers?

Cheers,

Brice

On Tue, 23 Nov 2010 12:20:43 -0600, CaveLamb
wrote:

Joe wrote:

Have been on a hundred boats with 25-72 inch props and had to chain
them down many times to prevent damage to the gears. As I said the
power is massive and you had better have heavy chains and binders.

Joe





There is no doubt that the prop will turn (or at lest want to) when
water flows past it.

But to develop any real power, the pitch of the blades has to change.
Think about it from the POV of the propeller.
When running and moving the boat, the prop attacks the water stream
at a fairly fine angle. Spinning, the prop takes a small bite of
water and sends it aft. Water meets the prop a small angle off of
the leading edge.

When not running, and just dragging through the water, the angle of
attack is huge. Water hits nearly flat on the face of the blades.

If you want to use the prop to generate electricity, to have any
kind of efficiency, and reduce drag, the prop blades need to change
pitch by about 90 degrees.

And all that just to reduce mechanical and speed losses to minimum.
They WILL still be there.


Some people seem to think that since it's a sailboat, and slow anyway,
that a little loss of speed is ok.

I'm of the other mind. Since it's already slow any additional losses
are unacceptable.

(trim yer sails, mate)


A lot of information on turbine water power at
http://en.wikipedia.org/wiki/Water_turbine
and apparently it is not "new technology" as the Romans used the
concept.

Cheers,

Brice

On Wed, 24 Nov 2010 07:37:46 +0700, Bruce
wrote:

You say "maintain speed and stability", do you have active
stabilizers?

Yes, Naiads.

http://www.naiad.com/Product_Flyer_162-302.pdf

On Nov 23, 4:44*am, Bruce wrote:
On Mon, 22 Nov 2010 17:49:24 -0800 (PST), Joe





wrote:
On Nov 22, 6:39*pm, Bruce wrote:
On Mon, 22 Nov 2010 08:54:03 -0800 (PST), Joe

wrote:
On Nov 22, 9:40 am, Wayne.B wrote:
On Mon, 22 Nov 2010 07:21:00 -0800 (PST), Joe

wrote:
Now directly couple a motor/generator that consists of a stator
winding employing a high pole count configuration, which allows for
high copper utilization (minimizing energy loss and cost), and a
hollow rotor upon which powerful rare earth permanent magnets are
mounted on the outer circumference coupled to a variable pitch prop
system and you can pump out some serious energy. The city buses that
are using these moters claim they capture 97% of the kinetic energy
developed while stopping.

Regardless of the capture mechanism, even at 100% efficiency, there is
only so much energy in a moving column of water and it is not a big
number when you are moving at sailing speeds. Now if you could get
that same column of water rolling down the side of a 1,000 ft
mountain, that's a whole different story. :-)

*I'm going to have to disagree with you Wayne. The amount of energy
coming off a shaft at sailing speed can be huge. The drag can be
offset by canvas with ease on a non-planing hull. If you capture 1 rpm
of energy for every 4 rmp's generated by sail, and can store that
energy you have a system that can work.

Now if a bus can capture 97% of the kinetic energy by stopping then
why can't a prop do the same ?
About the smallest CVP system available is in the high 30's low 40"
diameter.
You ever chain down a shaft to a 40" prop? You better have some strong
chain.

http://www.youtube.com/watch?v=6KSnH6DFA94*Not quite a 1000 ft drop
but plenty of power to harness.

Joe

Are you normally obtuse, or have you always gotten your technical
information from the movies?

The Youtube show you recommended states that it is a 200 ton sailing
boat. While your reference doesn't indicate the length of the vessel
but seems to say that they were doing 9 knots.

I found a reference to another 200 ton sailing vessel on the net - it
was 138 feet long. The hull speed for a 138 ft. vessel is about 16
knots so your reference was sailing at abut half hull speed (56%
actually). Hardly impressive.

Hardly, but enough to spin a big prop without much concern of the drag
the prop makes..

Are you serious? I've never seen anyone who doesn't care about drag.
The largest ships in the world are certainly extremely concerned about
it and in fact that is probably the major pitch that the paint
companies have when trying to sell to those companies. The Emma Mersk
brags about their super slippery paint that saves them 1,200 tons of
fuel a year. The funny looking "bulb bow" that you see on most modern
shipping is solely to reduce drag.

No kidding Bruce. It would be a trade off of drag for energy. On
Redcloud she had a 14X14 that was always dragging but she still had no
problem getting to hull speed.

And, by the bay, how many sailing yachts have you been on that were
fitted with a 40 inch propeller?

None by the bay;0). Never been on with a CVP propellor, or cort
nozzles either. Never been on one with a bow thruster , or forward
looking sonar, or a kite drive either. Never been on a hydrofoil
bigger than a rave...but there are ones out there.

Have been on a hundred boats with 25-72 inch props and had to chain
them down many times to prevent damage to the gears. As I said the
power is massive and you had better have heavy chains and binders.

Joe

You are undoubtedly correct in that big props turn bigger load but
equally have large drag factors.

Unfortunately there is no magic. You want to generate a lot of energy
at sail boat speeds 7 - 8 knots and you are going to have a
substantial amount of drag, which, of course, slows the boat and
requires a larger prop to generate the same power, which slows the
boat......

If the hull speed is 11 kts ..it's eleven knots even with a bobulious
bow.
So lets say you have a 15% drag, you hoist 20% more canvas.

Joe



Cheers,

Brice- Hide quoted text -

- Show quoted text -

On Nov 23, 12:20*pm, CaveLamb wrote:
Joe wrote:

*Have been on a hundred boats with 25-72 inch props and had to chain
them down many times to prevent damage to the gears. As I said the
power is massive and you had better have heavy chains and binders.

Joe

There is no doubt that the prop will turn (or at lest want to) when
water flows past it.

But to develop any real power, the pitch of the blades has to change.
Think about it from the POV of the propeller.
When running and moving the boat, the prop attacks the water stream
at a fairly fine angle. *Spinning, the prop takes a small bite of
water and sends it aft. *Water meets the prop a small angle off of
the leading edge.

When not running, and just dragging through the water, the angle of
attack is huge. *Water hits nearly flat on the face of the blades.

If you want to use the prop to generate electricity, to have any
kind of efficiency, and reduce drag, the prop blades need to change
pitch by about 90 degrees.

And all that just to reduce mechanical and speed losses to minimum.
They WILL still be there.

Some people seem to think that since it's a sailboat, and slow anyway,
that a little loss of speed is ok.

I'm of the other mind. *Since it's already slow any additional losses
are unacceptable.

(trim yer sails, mate)

Hello Richard, I agree 100% on the prop issues.
My research says this is the best option
http://www.hundestedpropeller.dk/?id=4172
They have a mechanical and hydralic systems. The mechanical seems the
best since the hydralic needs a pump running full time.

Joe


Joe

--

Richard Lamb
email me:
web site: *www.home.earthlink.net/~cavelamb

On Nov 22, 6:19*pm, Bruce wrote:
On Mon, 22 Nov 2010 07:21:00 -0800 (PST), Joe





wrote:
On Nov 22, 5:10*am, Bruce wrote:
On Sun, 21 Nov 2010 22:49:30 -0600, CaveLamb
wrote:

One of the problems using the engine propeller to turn an alternator
is that the prop pitch is all wrong.

By 90 degrees, in fact.

It works though, witness the bloke I mentioned that had an alternator
belted to the propshaft.... just that it doesn't produce much power.

Cheers,

Brice

Why not use stone wheels too Bruce, since you are talking about stone
age tech? Using a belt drive and a big alternator is not going to
capture much energy anything.

Now directly couple a motor/generator that consists of a stator
winding employing a high pole count configuration, which allows for
high copper utilization (minimizing energy loss and cost), and a
hollow rotor upon which powerful rare earth permanent magnets are
mounted on the outer circumference coupled to a variable pitch prop
system and you can pump out some serious energy. The city buses that
are using these moters claim they capture 97% of the kinetic energy
developed while stopping.

You are comparing apples to oranges.

Joe

How does, as you say "high copper content" decrease costs?

Cheers,

Brice- Hide quoted text -

- Show quoted text -

According to UQM" The stator is affixed to an aluminum housing, which
contains mounting end bells and bearings. This allows the rotor to be
suspended within the stator. Commutation of the machine is
accomplished electronically by sensing the position of the rotor in
relation to the stator, and intelligently pulsing electrical energy
into the stator such that the electric field generated by the stator
interacts with the magnetic field of the rotor producing rotational
motion (“motor operation”). Conversely, the application of rotational
motion to the rotor by an external force results in the generation of
electrical power (“generator operation”). UQM® machines can be
operated in either a forward or reverse direction of rotation and
either in motor or generator mode and can dynamically change from one
mode of operation to another in millisecond response time. The hollow
design of the rotor permits the packaging of other components such as
gears and electromechanical brakes in the interior of the machine.
These design features contribute to lower usage of copper and iron and
other materials generally (due to smaller package dimensions),
reducing manufacturing cost over those for conventional machines of
similar power. In addition, the utilization of neodymium-iron-boron
(“NdFeB”) magnet material in a wide range of consumer devices, such as
cell phones, disk drives and medical devices, has dramatically
improved the availability, performance and price of this material,
allowing us to price our advanced motors and controls competitively
with lesser performing conventional motors which we believe will
accelerate the rate of commercialization of our technology."

Joe

On Tue, 23 Nov 2010 06:15:07 -0500, Wayne.B
wrote:

On Tue, 23 Nov 2010 17:46:50 +0700, Bruce
wrote:

Out of curiosity, why chain the shaft? Are you running on one engine?
And, if you are how is it working for you. I tried it and it simply
dropped the speed by about half :-(

On our boat we can improve fuel efficiency by about 25% running on a
single engine assuming a speed of no more than about 1.1 SQRT LWL.

We have Detroit 6-71 2-cycle diesels which are not efficient at low
speeds. Running single engine gets operating RPMs up to a normal
level. This is useful on long passages in relatively light winds and
calm seas. If the wind kicks up we need more power to maintain speed
and stability.

Tough finding a solution to that.
Just a few thing things that popped into my head, probably none
practical.
Re-propping to get revs up on both engines - non-starter because
you're running 2 engines, and waste heat kills fuel savings.
Transmission that can run both props on one engine input.
Makes sense for cruising speed, but probably too expensive/complex.
Feathering props. Probably more drawbacks than gain.
Easily detached props. Read to dive far asea, hoist, and get caught
with only one prop when it squalls? Didn't think so.
My favorite lame-brain idea is streamlined remote operated prop cowls.
Close when prop not in use, open otherwise.
Insane.

Do you have trans lube/heat problems when freewheeling a prop?
If you lock it down, will you still get 25% fuel savings?
Lots of drag there.

--Vic

On Wed, 24 Nov 2010 09:48:30 -0600, Vic Smith
wrote:

We have Detroit 6-71 2-cycle diesels which are not efficient at low
speeds. Running single engine gets operating RPMs up to a normal
level. This is useful on long passages in relatively light winds and
calm seas. If the wind kicks up we need more power to maintain speed
and stability.

Tough finding a solution to that.
Just a few thing things that popped into my head, probably none
practical.
Re-propping to get revs up on both engines - non-starter because
you're running 2 engines, and waste heat kills fuel savings.
Transmission that can run both props on one engine input.
Makes sense for cruising speed, but probably too expensive/complex.

Running two engines is always less efficient than one engine,
everything else being equal. An engine in motion has lots of
frictional and parasitic losses - things like pumps, alternators and
valve trains for example. DD 6-71s have an additional parasitic loss
from spinning the blower.

Feathering props. Probably more drawbacks than gain.

Feathering props are good although complex, expensive and difficult to
repair in the boondocks.

Easily detached props. Read to dive far asea, hoist, and get caught
with only one prop when it squalls? Didn't think so.

Not on my boat although I understand that a guy with a GB49 went from
Hawaii to San Francisco that way.

My favorite lame-brain idea is streamlined remote operated prop cowls.
Close when prop not in use, open otherwise.
Insane.

Good out of the box thinking, just a few details... :-)

Do you have trans lube/heat problems when freewheeling a prop?
If you lock it down, will you still get 25% fuel savings?
Lots of drag there.

At slow trawler speeds it is not that big an issue. We start the
other engine once in a while to recirculate the transmission lube. I
also check the temp with a heat gun from time to time when I'm doing
my engine room checks.

In theory locking it down is more efficient than letting it spin.
Locking it down is potentially dangerous however unless a built in
shaft braking system is used.