On Fri, 19 Nov 2010 23:34:40 +0000, Justin C
wrote:

In article , Wayne.B wrote:
On Wed, 17 Nov 2010 08:28:04 -0800 (PST), Joe
wrote:

Do you plan to use the captured energy to supply house loads or to use
it as recharge/propulsion when the wind dies?- Hide quoted text -

- Show quoted text -

Both would be the goal.....zero emissions. They have some very good
re-generative systems and nickel-metal hydride and lithium-ion
batteries. The boat would have plenty of room for some huge battery
banks.

You could probably supply house loads with just solar panels and/or
wind generators. However I'm a bit skeptical about standby
propulsion regardless of battery banks size. By the time you drag
props that are big enough to capture significant power, you'd be
adding enough drag to considerably slow the boat. On the other hand
if you are just looking for talking points in a marketing plan, what
the heck.

quote
The GREEN MOTION system eliminates fossil fuel used by sailing
yachts in any way. Electrical energy is generated with the system and is
stored in batteries (lithium Iron Phosphate are optional). It will
generate sufficient energy to be used for propulsion, hot water, cooking
and all electrical equipment and navigation on board. When batteries are
fully charged or high speed is required (race) the lifted Motogens
eliminate the drag from the propulsion system and this increases the
speed of the yacht (between 5 - 15%).

Retractable Motogen
The electric retractable Motogen is new, light
weight, extremely efficient and better than any propulsion system ever
designed for yachts. Usable in all sailing yachts from 30 to 90 ft (9-30
m): monohull, catamaran or trimaran). Installation can be made inside
the hull in a monohull or on a retractable arm for multihull. 5 years of
extensive testing has been done with a ‘proof of concept’ sailing in
excess of 10.000 Nm.
/quote


URL:http://www.green-motion.com/

OK, it's a cat, and not up to Joe's cargo work, but some of the
technology must transfer. I don't fancy the cost of those li-ion
batteries though... but they do handle huge charging loads, charge
quickly, and deliver their full capacity, not just a small percentage of
it.

The idea of a boat that needs no fuel of any kind, other than that
required to sustain the crew, does appeal. No diesel for *anything*. I'm
sure that there are some cruisers out there who would find the cost of
one of these cats a whole lot cheaper when they factor in their diesel
usage over a few years.

Justin.

I suspect that the estimates of drag versus speed for the generator
propeller is highly optimistic. The best estimates I can find are that
the drag from a 3 bladed prop reduces speed by about 15%, not the 5 -
15% mentioned.

My own experience changing from a three bladed feathering prop to a
three bladed fixed pitch prop was that the speed reduction was
certainly very noticable.

Fromr one source http://www.ipoa.org.uk/?p=180 (unknown provenance):

quote:
The drag of a propeller is not easy to quantify but some
generalisations are in order such as,

The drag effect increases with speed – actually it increases with
the square of the speed, so faster hulls are penalised much more than
slower ones.
The average sailing speed is reduced by about 15% by the drag of a 3
bladed propeller of a size suited to propel a particular hull. When
there is a strong wind there is often sufficient power from the sails
to overcome the drag of the propeller and hull speed is achieved. As
the wind drops, the drag of the propeller becomes more significant and
in light winds it can seriously reduce sailing speed.
unquote:

If you want to spend a couple of bucks here is what appears to be a
peer reviewed indipendent study on the effects of props on drag
fromOcean Engineering, Volume 35, Issue 1, January 2008, Pages 28-40

/2008&_rdoc=1&_fmt=high&_orig=search&_origin=search &_sort=d&_docanchor=&view=c&_acct=C000050221&_vers ion=1&_urlVersion=0&_userid=10&md5=a7ab84dce94c502 4bf9bc438d2397827&searchtype=a

The abstract says:

All but the smallest classes of modern keelboats are fitted with
inboard engines and consequently, when making way under sail, the
craft experience parasitic drag due to trailing propellers and
associated appendages. The variety of screw configurations used on
sailing boats includes fixed-blade, feathering, and folding set-ups,
with blades numbering two or three. Although the magnitude of the
resultant drag is thought to have a significant influence on sailing
performance, the published literature having regard to this problem is
sparse. Here, the aim was to evaluate the drag effect of fixed-blade
propellers of types commonly used on sailing craft. The results of
towing tank tests on full-scale propellers are presented for the
locked shaft condition; these are presented along with reconfigured
data from the few previously published sources. For the case in which
the propeller is allowed to rotate, tests were conducted on a typical
screw with a range of braking torques being applied. It was
hypothesised that the performance coefficients of the Wageningen
B-Screw Series could be used to characterise adequately the types of
screw of interest and that these could be extrapolated to enable
prediction of the drag of a freewheeling propeller; an assessment of
this formed part of the investigation.

Cheers,

Bruce

In article , Bruce wrote:
On Fri, 19 Nov 2010 23:34:40 +0000, Justin C
wrote:

quote
The GREEN MOTION system eliminates fossil fuel used by sailing
yachts in any way. Electrical energy is generated with the system and is
stored in batteries (lithium Iron Phosphate are optional). It will
generate sufficient energy to be used for propulsion, hot water, cooking
and all electrical equipment and navigation on board. When batteries are
fully charged or high speed is required (race) the lifted Motogens
eliminate the drag from the propulsion system and this increases the
speed of the yacht (between 5 - 15%).

Retractable Motogen
The electric retractable Motogen is new, light
weight, extremely efficient and better than any propulsion system ever
designed for yachts. Usable in all sailing yachts from 30 to 90 ft (9-30
m): monohull, catamaran or trimaran). Installation can be made inside
the hull in a monohull or on a retractable arm for multihull. 5 years of
extensive testing has been done with a ‘proof of concept’ sailing in
excess of 10.000 Nm.
/quote


URL:http://www.green-motion.com/

I suspect that the estimates of drag versus speed for the generator
propeller is highly optimistic. The best estimates I can find are that
the drag from a 3 bladed prop reduces speed by about 15%, not the 5 -
15% mentioned.

They put a small amount of current through the motors as the same time
as using them to generate, this partially compensates for the drag -
according to last month's Yachting Monthly feature.


Justin.

--
Justin C, by the sea.

On Sat, 20 Nov 2010 19:20:11 +0000, Justin C
wrote:

In article , Bruce wrote:
On Fri, 19 Nov 2010 23:34:40 +0000, Justin C
wrote:

quote
The GREEN MOTION system eliminates fossil fuel used by sailing
yachts in any way. Electrical energy is generated with the system and is
stored in batteries (lithium Iron Phosphate are optional). It will
generate sufficient energy to be used for propulsion, hot water, cooking
and all electrical equipment and navigation on board. When batteries are
fully charged or high speed is required (race) the lifted Motogens
eliminate the drag from the propulsion system and this increases the
speed of the yacht (between 5 - 15%).

Retractable Motogen
The electric retractable Motogen is new, light
weight, extremely efficient and better than any propulsion system ever
designed for yachts. Usable in all sailing yachts from 30 to 90 ft (9-30
m): monohull, catamaran or trimaran). Installation can be made inside
the hull in a monohull or on a retractable arm for multihull. 5 years of
extensive testing has been done with a ‘proof of concept’ sailing in
excess of 10.000 Nm.
/quote


URL:http://www.green-motion.com/

I suspect that the estimates of drag versus speed for the generator
propeller is highly optimistic. The best estimates I can find are that
the drag from a 3 bladed prop reduces speed by about 15%, not the 5 -
15% mentioned.

They put a small amount of current through the motors as the same time
as using them to generate, this partially compensates for the drag -
according to last month's Yachting Monthly feature.


Justin.


Perhaps I'm a cynic but it sounds like pie in the sky.

Of course if they put a small amount of current through the device,
i.e., power it, it will result in less drag. But of course it also
results in less net current generated.

Frankly it sounds very much like a perpetual motion machine.

Cheers,

Bruce

In article , Bruce wrote:
On Sat, 20 Nov 2010 19:20:11 +0000, Justin C

They put a small amount of current through the motors as the same time
as using them to generate, this partially compensates for the drag -
according to last month's Yachting Monthly feature.

Perhaps I'm a cynic but it sounds like pie in the sky.

I'm prepared to suspend belief, I'm only quoting from the article.
However, if they have achieved what the article says, then that's
something quite special.


Of course if they put a small amount of current through the device,
i.e., power it, it will result in less drag. But of course it also
results in less net current generated.

Frankly it sounds very much like a perpetual motion machine.

Not quite perpetual motion, they're only claiming that they can reduce
the drag of the props to 5% by supplying some power.

Be sceptical, if it's for real we'll hear about it from other sources
over time, even some that we trust.

Justin.

--
Justin C, by the sea.

On Sun, 21 Nov 2010 07:19:02 +0700, Bruce
wrote:

Frankly it sounds very much like a perpetual motion machine.

It's definitely not perpetual motion but it does depend on a number of
assumptions that may not hold true in the real world. Extracting
energy from spinning props is definitely possible under the right
conditions but my calculations show that the maximum power available
is relatively low, quite possibly enough to supply house loads, but
very unlikely enough to recharge a large battery bank.

On Sat, 20 Nov 2010 21:18:30 -0500, Wayne.B
wrote:

On Sun, 21 Nov 2010 07:19:02 +0700, Bruce
wrote:

Frankly it sounds very much like a perpetual motion machine.

It's definitely not perpetual motion but it does depend on a number of
assumptions that may not hold true in the real world. Extracting
energy from spinning props is definitely possible under the right
conditions but my calculations show that the maximum power available
is relatively low, quite possibly enough to supply house loads, but
very unlikely enough to recharge a large battery bank.


I knew one person who had a propeller shaft driven alternator on a 40
ft. sloop and metered it's output. He said that it produced
electricity but not much and removed it to install a propshaft driven
bilge pump - bloody great thing it was. I used to offer to chop a hole
in the hole so he could test it but he never seemed to be interested.

A second had one of those towed generators and said much the same - it
did produce electricity but he still needed to run the engine
frequently when sailing unless he was very, very careful with the
electricity. He had a vane steerer so the only "can't turn it off" he
had running would have been his GPS and maybe his nav lights, but I
doubt that he would use them off shore.

And these were blokes who did sail off shore - used to quote speed in
miles per day :-) Along shore I think it would be worse. Hopefully
anyone who tries this system keeps a big outboard on board :-(

Cheers,

Brice

On Nov 19, 10:13*pm, Bruce wrote:
On Fri, 19 Nov 2010 23:34:40 +0000, Justin C





wrote:
In article , Wayne.B wrote:
On Wed, 17 Nov 2010 08:28:04 -0800 (PST), Joe
wrote:

Do you plan to use the captured energy to supply house loads or to use
it as recharge/propulsion when the wind dies?- Hide quoted text -

- Show quoted text -

Both would be the goal.....zero emissions. They have some very good
re-generative systems and nickel-metal hydride and lithium-ion
batteries. The boat would have plenty of room for some huge battery
banks.

You could probably supply house loads with just solar panels and/or
wind generators. * However I'm a bit skeptical about standby
propulsion regardless of battery banks size. * By the time you drag
props that are big enough to capture significant power, you'd be
adding enough drag to considerably slow the boat. *On the other hand
if you are just looking for talking points in a marketing plan, what
the heck.

quote
* *The GREEN MOTION system eliminates fossil fuel used by sailing
yachts in any way. Electrical energy is generated with the system and is
stored in batteries (lithium Iron Phosphate are optional). It will
generate sufficient energy to be used for propulsion, hot water, cooking
and all electrical equipment and navigation on board. When batteries are
fully charged or high speed is required (race) the lifted Motogens
eliminate the drag from the propulsion system and this increases the
speed of the yacht (between 5 - 15%).

* *Retractable Motogen
* *The electric retractable Motogen is new, light
weight, extremely efficient and better than any propulsion system ever
designed for yachts. Usable in all sailing yachts from 30 to 90 ft (9-30
m): monohull, catamaran or trimaran). Installation can be made inside
the hull in a monohull or on a retractable arm for multihull. 5 years of
extensive testing has been done with a ‘proof of concept’ sailing in
excess of 10.000 Nm.
/quote

URL:http://www.green-motion.com/

OK, it's a cat, and not up to Joe's cargo work, but some of the
technology must transfer. I don't fancy the cost of those li-ion
batteries though... but they do handle huge charging loads, charge
quickly, and deliver their full capacity, not just a small percentage of
it.

The idea of a boat that needs no fuel of any kind, other than that
required to sustain the crew, does appeal. No diesel for *anything*. I'm
sure that there are some cruisers out there who would find the cost of
one of these cats a whole lot cheaper when they factor in their diesel
usage over a few years.

* Justin.

I suspect that the estimates of *drag versus speed for the generator
propeller is highly optimistic. The best estimates I can find are that
the drag from a 3 bladed prop reduces speed by about 15%, not the 5 -
15% mentioned.

My own experience changing from a three bladed feathering prop to a
three bladed fixed pitch prop was that the speed reduction was
certainly very noticable.

Fromr one sourcehttp://www.ipoa.org.uk/?p=180(unknown provenance):

quote:
The drag of a propeller is not easy to quantify but some
generalisations are in order such as,

The drag effect increases with speed – actually it increases with
the square of the speed, so faster hulls are penalised much more than
slower ones.

This is true. You chain a single shaft on a quad screw crewboat you
drop from 25kts to 11kts.

The average sailing speed is reduced by about 15% by the drag of a 3
bladed propeller of a size suited to propel a particular hull. When
there is a strong wind there is often sufficient power from the sails
to overcome the drag of the propeller and hull speed is achieved.

I think thats right on for a sailing vessel, around 15% for any
displacement hull, easy to overcome with sail.

As
the wind drops, the drag of the propeller becomes more significant and
in light winds it can seriously reduce sailing speed.


unquote:

If you want to spend a couple of bucks here is what appears to be a
peer reviewed *indipendent study on the effects of props on drag
fromOcean Engineering, Volume 35, Issue 1, January 2008, Pages 28-40

/2008&_rdoc=1&_fmt=high&_orig=search&_origin=search &_sort=d&_docanchor=&vie*w=c&_acct=C000050221&_ver sion=1&_urlVersion=0&_userid=10&md5=a7ab84dce94c50 *24bf9bc438d2397827&searchtype=a

The abstract says:

All but the smallest classes of modern keelboats are fitted with
inboard engines and consequently, when making way under sail, the
craft experience parasitic drag due to trailing propellers and
associated appendages. The variety of screw configurations used on
sailing boats includes fixed-blade, feathering, and folding set-ups,
with blades numbering two or three. Although the magnitude of the
resultant drag is thought to have a significant influence on sailing
performance, the published literature having regard to this problem is
sparse. Here, the aim was to evaluate the drag effect of fixed-blade
propellers of types commonly used on sailing craft. The results of
towing tank tests on full-scale propellers are presented for the
locked shaft condition; these are presented along with reconfigured
data from the few previously published sources. For the case in which
the propeller is allowed to rotate, tests were conducted on a typical
screw with a range of braking torques being applied. It was
hypothesised that the performance coefficients of the Wageningen
B-Screw Series could be used to characterise adequately the types of
screw of interest and that these could be extrapolated to enable
prediction of the drag of a freewheeling propeller; an assessment of
this formed part of the investigation.

Cheers,

Bruce- Hide quoted text -

- Show quoted text -

Do they mention the difference from a chained shaft to a free
wheeling prop. I've heard a chained non turing prop provides less
drag.

Joe

On Nov 20, 1:20*pm, Justin C wrote:
In article , Bruce wrote:
On Fri, 19 Nov 2010 23:34:40 +0000, Justin C
wrote:

quote
* * * *The GREEN MOTION system eliminates fossil fuel used by sailing
yachts in any way. Electrical energy is generated with the system and is
stored in batteries (lithium Iron Phosphate are optional). It will
generate sufficient energy to be used for propulsion, hot water, cooking
and all electrical equipment and navigation on board. When batteries are
fully charged or high speed is required (race) the lifted Motogens
eliminate the drag from the propulsion system and this increases the
speed of the yacht (between 5 - 15%).

* * * *Retractable Motogen
* * * *The electric retractable Motogen is new, light
weight, extremely efficient and better than any propulsion system ever
designed for yachts. Usable in all sailing yachts from 30 to 90 ft (9-30
m): monohull, catamaran or trimaran). Installation can be made inside
the hull in a monohull or on a retractable arm for multihull. 5 years of
extensive testing has been done with a ‘proof of concept’ sailing in
excess of 10.000 Nm.
/quote

URL:http://www.green-motion.com/

I suspect that the estimates of *drag versus speed for the generator
propeller is highly optimistic. The best estimates I can find are that
the drag from a 3 bladed prop reduces speed by about 15%, not the 5 -
15% mentioned.

They put a small amount of current through the motors as the same time
as using them to generate, this partially compensates for the drag -
according to last month's Yachting Monthly feature.

* *Justin.

--
Justin C, by the sea.- Hide quoted text -

- Show quoted text -

I guess they could not afford a CVP prop to reduce drag when needed.

Joe

On Nov 20, 6:19*pm, Bruce wrote:
On Sat, 20 Nov 2010 19:20:11 +0000, Justin C





wrote:
In article , Bruce wrote:
On Fri, 19 Nov 2010 23:34:40 +0000, Justin C
wrote:

quote
* *The GREEN MOTION system eliminates fossil fuel used by sailing
yachts in any way. Electrical energy is generated with the system and is
stored in batteries (lithium Iron Phosphate are optional). It will
generate sufficient energy to be used for propulsion, hot water, cooking
and all electrical equipment and navigation on board. When batteries are
fully charged or high speed is required (race) the lifted Motogens
eliminate the drag from the propulsion system and this increases the
speed of the yacht (between 5 - 15%).

* *Retractable Motogen
* *The electric retractable Motogen is new, light
weight, extremely efficient and better than any propulsion system ever
designed for yachts. Usable in all sailing yachts from 30 to 90 ft (9-30
m): monohull, catamaran or trimaran). Installation can be made inside
the hull in a monohull or on a retractable arm for multihull. 5 years of
extensive testing has been done with a ‘proof of concept’ sailing in
excess of 10.000 Nm.
/quote

URL:http://www.green-motion.com/

I suspect that the estimates of *drag versus speed for the generator
propeller is highly optimistic. The best estimates I can find are that
the drag from a 3 bladed prop reduces speed by about 15%, not the 5 -
15% mentioned.

They put a small amount of current through the motors as the same time
as using them to generate, this partially compensates for the drag -
according to last month's Yachting Monthly feature.

* Justin.

Perhaps I'm a cynic but it sounds like pie in the sky.

Of course if they put a small amount of current through the device,
i.e., power it, it will result in less drag. But of course it also
results in less net current generated.

Frankly it sounds very much like a perpetual motion machine.

Cheers,

Bruce- Hide quoted text -

- Show quoted text -

If they did not have sail energy input I would agree. But a full set
of sails in a nice breeze can generate massive amount of power input.

Joe

On Sat, 20 Nov 2010 21:18:30 -0500, Wayne.B
wrote:

It's definitely not perpetual motion but it does depend on a number of
assumptions that may not hold true in the real world. Extracting
energy from spinning props is definitely possible under the right
conditions but my calculations show that the maximum power available
is relatively low, quite possibly enough to supply house loads, but
very unlikely enough to recharge a large battery bank.

Wayne, you hit the nail on the head as they say.

As most of you know I spent about 6 years living on solar and wind
power, and built electric cars, trikes and motorcycles. So I'm all for
renewable energy and have put my money where my mouth is. But, and a
very big BUT, there are very severe limitations as to what it can do.

You just can't get vast amounts of power from wind, sun and water
unless you take up vast amounts of space and spend vast amounts of
money. One thing that comes to mind. Recently the town here dedicated
a Windspire wind generator at the library. The wind gen and everything
else was donated by various companies in town. It's a 30 foot high
thing that maxes at 1,200 Watts. Of course, like most that figure is
with a 65 MPH wind. More like 100 Watts at the normal 15 MPH winds
here. Anyway, they stated that it should save the libray about $200 a
year in electric costs. Their normal electric bill is about $5,000 a
year!

I just had a thought that might illustrate the problem, at least as
far as propulsion goes. Instead of looking at Amps or Watts directly,
lets look at Horsepower.

1 HP is 746 Watts. Now, to charge a battery there are losses, and to
get that 1 HP there are also motor losses. So to make it easy let's
say 1 HP out is 1,000 Watts, or 1 KW, in. That's 74.6% efficientcy.

Let's further say 10 HP is what we need to power the boat at a decent
speed. In the real world, probably 5 KTs for a 30 footer. Our 30
footer with 10 HP motor has 16 golf cart batteries in series for 96
Volts and 21.6 KWH. This will give us 2 hours and 10 minutes of run
time to a flat battery bank.

Most of what I've read about using an alternator on the prop state the
output is about 10 Amps, so at 13.6 Volts this is 136 Watt Hours, or
..136 KWH. Traveling 10 hours a day gives us 1.36 KWH per day. So a 10
hour sail would let us motor for 8 minutes and 10 seconds.

One could hang a big prop down there, optimised to drive an alternator
and maybe get 50 Amps with a large reduction in speed. That would give
us about 40 minutes run time.

How about solar? If we cover that entire 30 footer in solar panels, we
should be able to get about 3,000 watts. At a cost of $15,000 plus
controller at the current $5 per watt. This will give us between 9 KWH
and 18 KWH per day, depending on latitude and season.

Sooo... We can run under power from 54 mintes to 1 hour and 48 minutes
per sunny day.

We all know air conditioners are power hogs. A 15,000 BTU marine AC
takes about 1.5 HP. So imagine generating enough power to run 6-1/2 of
your AC's. That what you need to power a 30 footer.

Rick