When things are turning there is wear. The driveline is designed to, primarily, transmit power in the other direction. My experiences using the PSA on the Super Maramu caused a half Knot loss in speed compared to a stopped and feathered Max or Autoprop.

Joel F. Potter
Cruising Yacht Specialist.
Amel's Sole Associate For America.
Sent from my iPhone.
Office: 954 462 5869
Cell: 954 812 2485

Joel, I have a fixed prop, maybe thats why I do not see as much speed
differential when the psa is engaged .Freewheeling,are the gears adequately
lubercated and is it harmful to put transmission in reverse while sailing and
prop spinning foreward? I agree that there is wear anytime anything moves, yet
Amel installed the psa to be used. Do you think the degree of wear warrants
concern to the point where you would be reluctant to use it ?

Thanks, Pat SM 123

Come on get real - we have a gearbox/transmission designed for what (to
transmit 50 or so HP in Forward and Reverse) and you think you can damage it
by driving a small alternator Please folks that suggestion is just so far
off the mark it makes me want to write some rather nasty comments.

For those with telepathic or cryptic powers WPAYO!!!

regards

David



On 15 July 2011 15:46, Joel Potter <jfpottercys@...> wrote:

**


When things are turning there is wear. The driveline is designed to,
primarily, transmit power in the other direction. My experiences using the
PSA on the Super Maramu caused a half Knot loss in speed compared to a
stopped and feathered Max or Autoprop.


Joel F. Potter
Cruising Yacht Specialist.
Amel's Sole Associate For America.
Sent from my iPhone.
Office: 954 462 5869
Cell: 954 812 2485

On Jul 15, 2011, at 10:19 AM, Pat <sailw32@...> wrote:

Joel, There has been postings suggesting wear to the drive train

associated with the prop freewheeling while the PSA is engaged. Can you
answer a couple questions?

First, are the gears being lubricated while freewheeling and do you

believe there is an amount of wear occurring to be concerned about? Second,
while sailing and the prop spinning, can the transmission be damaged putting
it reverse? I really like the PSA, I went sailing last night for about 5
hrs. in 15 knts. and came in with higher voltage than when I left my
mooring. One last comment, people mention losing half a knt. while the PSA
is engaged. I have never seen that kind of speed loss, while you have to
lose some speed, it has to be a fraction of a knt., for I cannot see it
reflected on the SOG., any thoughts on speed loss?

Thanks,
Pat SM 123
PS. Thanks, for your help in regards to my re-rig this past spring, took

your suggestion painted entire mast, lots of work but looks new.

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

David - I agree. Capt Amel always thought through his equipment, and if he fitted a PSA you can bet your life he would have thought through the need for:
1. A lubrication system that works whether the prop is driven - either way, or idling
2. A hurth gearbox that can rotate freely in neutral when not under engine load.

On my santorin there was a notice - in french which said - when sailing NEVER select forward gear!

To stop the prop (fixed pitch) you select reverse and with a resounding "KLONK" the shaft stops rotating.

In 20 years and 58,000 sea miles I've done it twice........to clear lines around the prop


Mike & Chris
Akwaaba
SN027



________________________________
From: David Mackintosh <sv.highland.fling@...>
To: amelyachtowners@...
Sent: Saturday, July 16, 2011 3:07 AM
Subject: Re: [Amel] Re: Maramu prop shaft alternator

Come on get real - we have a gearbox/transmission designed for what (to
transmit 50 or so HP in Forward and Reverse) and you think you can damage it
by driving a small alternator  Please folks that suggestion is just so far
off the mark it makes me want to write some rather nasty comments.

For those with telepathic or cryptic powers WPAYO!!!

regards

David



On 15 July 2011 15:46, Joel Potter <jfpottercys@...> wrote:

**


When things are turning there is wear. The driveline is designed to,
primarily, transmit power in the other direction. My experiences using the
PSA on the Super Maramu caused a half Knot loss in speed compared to a
stopped and feathered Max or Autoprop.


Joel F. Potter
Cruising Yacht Specialist.
Amel's Sole Associate For America.
Sent from my iPhone.
Office: 954 462 5869
Cell: 954 812 2485

On Jul 15, 2011, at 10:19 AM, Pat <sailw32@...> wrote:

Joel, There has been postings suggesting wear to the drive train

associated with the prop freewheeling while the PSA is engaged. Can you
answer a couple questions?

First, are the gears being lubricated while freewheeling and do you

believe there is an amount of wear occurring to be concerned about? Second,
while sailing and the prop spinning, can the transmission be damaged putting
it reverse? I really like the PSA, I went sailing last night for about 5
hrs. in 15 knts. and came in with higher voltage than when I left my
mooring. One last comment, people mention losing half a knt. while the PSA
is engaged. I have never seen that kind of speed loss, while you have to
lose some speed, it has to be a fraction of a knt., for I cannot see it
reflected on the SOG., any thoughts on speed loss?

Thanks,
Pat SM 123
PS. Thanks, for your help in regards to my re-rig this past spring, took

your suggestion painted entire mast, lots of work but looks new.

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

 

[Non-text portions of this message have been removed]



------------------------------------

Yahoo! Groups Links



[Non-text portions of this message have been removed]

When installed on shaft type configurations it's not an issue. On the C drive it's not the power of the charging sys it is the Rotational cycles of of bevel gears. Wear of the gear teeth and bearings come into play. Think about it there are three transmissions turning. And by the way you must have the "free wheeling" Hurth to run the shaft Gen sys. The Hurth uses auto trans fluid that does a much better job than 40 Wt motor oil in a "splash" system. Again it is NOT the power of the alternator but wear.

Regards. FOR SAIL IN ANNAPOLIS

Richard Piller

Cell 603 767 5330

"brokerage beyond your expectations"

Capt Amel also used hank on sails for many years. In fact the original design of the Maramu was for hank on sails, not furling. So using this logic we could justify hank on sails.

Capt Amel made decisions based on the technology available at the time. What was a great thought in the 1980's is not necessarily the best choice today. While I would not necessarily scrap a PSA if I had one, I wouldn't be inclined to install it given the alternatives that produce reasonable amounts of power without slowing the boat by half a knot.

A couple of things to think about:
• If a PSA is generating 20 amps @ 13 volts, that's 260 watts which is about 1/3 HP. So you need a motive force equal to that level of drag to overcome it. Hard to imagine that that level of drag would cost the boat 1/2 kt.
• Also, it would seem to be no different if you were "using" 1/3 HP of motive force to generate the power with either a PSA or a wind generator, and I've never heard anyone say they were losing 1/2 kt because of a wind gen.
• In any case, if your boat has a fixed prop, the prop/shaft/gearbox is already generating drag so the PSA would just be incremental on top of that.
• But we really need a marine architect to figure out the actual drag/HP required and tradeoffs.
Daves/v Air OpsMaramu #104

To: amelyachtowners@...
From: dave_benjamin@...
Date: Tue, 19 Jul 2011 03:15:47 +0000
Subject: [Amel] Re: Maramu prop shaft alternator




























Capt Amel also used hank on sails for many years. In fact the original design of the Maramu was for hank on sails, not furling. So using this logic we could justify hank on sails.



Capt Amel made decisions based on the technology available at the time. What was a great thought in the 1980's is not necessarily the best choice today. While I would not necessarily scrap a PSA if I had one, I wouldn't be inclined to install it given the alternatives that produce reasonable amounts of power without slowing the boat by half a knot.



--- In amelyachtowners@..., Chris Smither <yachtakwaaba@...> wrote:

David - I agree. Capt Amel always thought through his equipment, and if he fitted a PSA you can bet your life he would have thought through the need for:

1. A lubrication system that works whether the prop is driven - either way, or idling

2. A hurth gearbox that can rotate freely in neutral when not under engine load.

On my santorin there was a notice - in french which said - when sailing NEVER select forward gear!

To stop the prop (fixed pitch) you select reverse and with a resounding "KLONK" the shaft stops rotating.

In 20 years and 58,000 sea miles I've done it twice........to clear lines around the prop

Mike & Chris

Akwaaba

SN027

________________________________

From: David Mackintosh <sv.highland.fling@...>

To: amelyachtowners@...

Sent: Saturday, July 16, 2011 3:07 AM

Subject: Re: [Amel] Re: Maramu prop shaft alternator

Come on get real - we have a gearbox/transmission designed for what (to

transmit 50 or so HP in Forward and Reverse) and you think you can damage it

by driving a small alternator Please folks that suggestion is just so far

off the mark it makes me want to write some rather nasty comments.

For those with telepathic or cryptic powers WPAYO!!!

regards

David

On 15 July 2011 15:46, Joel Potter <jfpottercys@...> wrote:

**

When things are turning there is wear. The driveline is designed to,

primarily, transmit power in the other direction. My experiences using the

PSA on the Super Maramu caused a half Knot loss in speed compared to a

stopped and feathered Max or Autoprop.

Joel F. Potter

Cruising Yacht Specialist.

Amel's Sole Associate For America.

Sent from my iPhone.

Office: 954 462 5869

Cell: 954 812 2485

On Jul 15, 2011, at 10:19 AM, Pat <sailw32@...> wrote:

Joel, There has been postings suggesting wear to the drive train

associated with the prop freewheeling while the PSA is engaged. Can you

answer a couple questions?

First, are the gears being lubricated while freewheeling and do you

believe there is an amount of wear occurring to be concerned about? Second,

while sailing and the prop spinning, can the transmission be damaged putting

it reverse? I really like the PSA, I went sailing last night for about 5

hrs. in 15 knts. and came in with higher voltage than when I left my

mooring. One last comment, people mention losing half a knt. while the PSA

is engaged. I have never seen that kind of speed loss, while you have to

lose some speed, it has to be a fraction of a knt., for I cannot see it

reflected on the SOG., any thoughts on speed loss?

Thanks,

Pat SM 123

PS. Thanks, for your help in regards to my re-rig this past spring, took

your suggestion painted entire mast, lots of work but looks new.

[Non-text portions of this message have been removed]

------------------------------------

Yahoo! Groups Links

[Non-text portions of this message have been removed]

Hi to all. Regarding all the chatter about the shaft driven alternator; keep in mind that the non "C" drive or direct drive transmissions were designed to free wheel in neutral. We had such a system on our first AMEL with a fixed prop it worked great with no noticeable loss of boat speed. When we explored re powering we found thar Hurth offer both locked and free wheeling transmissions. They are internally different in how they are lubed and cooled. There was an option on the "C" drive for an alternator that came with a freewheeling transmission. We use a wind Gen today on our SM 209 we don't have to be moving to get a charge.

Regards Sm 209 FOR SALE IN ANNAPOLIS

Richard Piller

Cell 603 767 5330

"brokerage beyond your expectations"

On Jul 18, 2011, at 23:15, "Dave_Benjamin" <dave_benjamin@...> wrote:

Capt Amel also used hank on sails for many years. In fact the original design of the Maramu was for hank on sails, not furling. So using this logic we could justify hank on sails.

Capt Amel made decisions based on the technology available at the time. What was a great thought in the 1980's is not necessarily the best choice today. While I would not necessarily scrap a PSA if I had one, I wouldn't be inclined to install it given the alternatives that produce reasonable amounts of power without slowing the boat by half a knot.

--- In amelyachtowners@..., Chris Smither <yachtakwaaba@...> wrote:

David - I agree. Capt Amel always thought through his equipment, and if he fitted a PSA you can bet your life he would have thought through the need for:
1. A lubrication system that works whether the prop is driven - either way, or idling
2. A hurth gearbox that can rotate freely in neutral when not under engine load.

On my santorin there was a notice - in french which said - when sailing NEVER select forward gear!

To stop the prop (fixed pitch) you select reverse and with a resounding "KLONK" the shaft stops rotating.

In 20 years and 58,000 sea miles I've done it twice........to clear lines around the prop


Mike & Chris
Akwaaba
SN027



________________________________
From: David Mackintosh <sv.highland.fling@...>
To: amelyachtowners@...
Sent: Saturday, July 16, 2011 3:07 AM
Subject: Re: [Amel] Re: Maramu prop shaft alternator

Come on get real - we have a gearbox/transmission designed for what (to
transmit 50 or so HP in Forward and Reverse) and you think you can damage it
by driving a small alternator Please folks that suggestion is just so far
off the mark it makes me want to write some rather nasty comments.

For those with telepathic or cryptic powers WPAYO!!!

regards

David



On 15 July 2011 15:46, Joel Potter <jfpottercys@...> wrote:

**


When things are turning there is wear. The driveline is designed to,
primarily, transmit power in the other direction. My experiences using the
PSA on the Super Maramu caused a half Knot loss in speed compared to a
stopped and feathered Max or Autoprop.


Joel F. Potter
Cruising Yacht Specialist.
Amel's Sole Associate For America.
Sent from my iPhone.
Office: 954 462 5869
Cell: 954 812 2485

On Jul 15, 2011, at 10:19 AM, Pat <sailw32@...> wrote:

Joel, There has been postings suggesting wear to the drive train

associated with the prop freewheeling while the PSA is engaged. Can you
answer a couple questions?

First, are the gears being lubricated while freewheeling and do you

believe there is an amount of wear occurring to be concerned about? Second,
while sailing and the prop spinning, can the transmission be damaged putting
it reverse? I really like the PSA, I went sailing last night for about 5
hrs. in 15 knts. and came in with higher voltage than when I left my
mooring. One last comment, people mention losing half a knt. while the PSA
is engaged. I have never seen that kind of speed loss, while you have to
lose some speed, it has to be a fraction of a knt., for I cannot see it
reflected on the SOG., any thoughts on speed loss?

Thanks,
Pat SM 123
PS. Thanks, for your help in regards to my re-rig this past spring, took

your suggestion painted entire mast, lots of work but looks new.

[Non-text portions of this message have been removed]



------------------------------------

Yahoo! Groups Links



[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

Daves, I agree,If you had a folding prop you may see a 1/2 knt loss, I have
a fixed prop and I cannot detect a speed loss although there has to be
some, nothing is for nothing. I also agree a wind generator also creates drag of
course. Pat

Pat,
We have a Sharki with a fixed prop and standard shaft drive and I too cannot notice any reduction in speed, although as you say nothing is for nothing.
Graham

From: "sailw32@..." <sailw32@...>
To: amelyachtowners@...
Sent: Tuesday, 19 July 2011, 13:19
Subject: Re: [Amel] Re: Maramu prop shaft alternator


 

Daves, I agree,If you had a folding prop you may see a 1/2 knt loss, I have
a fixed prop and I cannot detect a speed loss although there has to be
some, nothing is for nothing. I also agree a wind generator also creates drag of
course. Pat






[Non-text portions of this message have been removed]

Thanks, Richard, for not responding in kind.  It's nice that so many make an effort to help others out, and only a few who act like it's some kind of p..ing contest.  Personally, I like to hear all sides of an issue...but am put off when someone presents their thoughts as though anyone who thinks differently is a dimwit.KentSM243Kristy


[Non-text portions of this message have been removed]

I'm a bit confused about the comparison in losses between the PSA and a wind generator. Water is far denser than air. The prop becomes a speed brake of sort. I'm not a physicist but I'd wager that amp for amp the performance loss with a wind generator is negligible compared to a PSA.

I think you will find a wind generator is not really usable when sailing in
decent winds and seas as gyroscopic effects and precession all start to have
a serious effect.

You are correct of course water being denser than air it is much easier to
extract power from a water driven propeller. BUT i think you miss the point
- lets say a PSA producing 10/15 Amp takes 1.5 HP to drive That HP has to
come from somewhere - the sails :-) To get your say what 22 metric ton
Amel up to hull speed is going to take say 80 HP so the losses assuming
they can be measured in a real live real time situation are going to be
insignificant really

Plus if you have 150/200 HP from your sails you have an excess of power and
since your Amel cant get up and plane - you have oodles of spare free HP to
drive your PSA. Any time you have more power from your sails than that
needed to drive the boat at hull speed..there will be no actual loss of
performance when using the PSA.

Actual real time real life reports on the PAS performance say the losses are
insignificant - not really measurable.

Now lets look at the trasmission designed to drive this 22MT boat with say
70 SHP..............do you really think you can damage that transmission in
any way by powering a 1.5 HP PSA with it? I think NOT!!!

IF anyone wants to dump their PSA then please contact me i would love to
have it :-)

regards

David

On 20 July 2011 00:13, Dave_Benjamin <dave_benjamin@...> wrote:

**


I'm a bit confused about the comparison in losses between the PSA and a
wind generator. Water is far denser than air. The prop becomes a speed brake
of sort. I'm not a physicist but I'd wager that amp for amp the performance
loss with a wind generator is negligible compared to a PSA.

[Non-text portions of this message have been removed]

Do those of you with wind generators use them when at sea?  Do you see any problems with performance as the boat moves with the seas?  I'm not experienced with either wind or PSA generators, but with wind it seems to me the wind is driving the wind generator essentially independently of what it's doing to the sails, unless the wind is coming from astern and interrupting the flow of air on the sails.  If you're dragging a fixed prop it wouldn't seem to make much of a difference using a PSA, but if you're using a feathering prop as many are, the turning prop would seem to me to create additional drag.
 
I'm guessing  that just the additional turning of the gears for hours on end would, at some point, create additional wear on them.  How much, significant...I wouldn't hazard a guess.
 
When I do finally get retired and head to the S. Pac, I'll consider both, and solar as well.
 
This has been a great discussion...thanks to all.
Kent
SM 243
Kristy

I put a KISS wind generator on my last boat. The engineering was superb. No
problems with 10-15,000 miles on it.

Cheap and simple.

Fair Winds

Eric

Amel Super Maramu #376 Kimberlite





_____

From: amelyachtowners@...
[mailto:amelyachtowners@...] On Behalf Of Kent Robertson
Sent: Tuesday, July 19, 2011 8:21 PM
To: amelyachtowners@...
Subject: Re: [Amel] Re: Maramu prop shaft alternator





Do those of you with wind generators use them when at sea? Do you see any
problems with performance as the boat moves with the seas? I'm not
experienced with either wind or PSA generators, but with wind it seems to me
the wind is driving the wind generator essentially independently of what
it's doing to the sails, unless the wind is coming from astern and
interrupting the flow of air on the sails. If you're dragging a fixed prop
it wouldn't seem to make much of a difference using a PSA, but if you're
using a feathering prop as many are, the turning prop would seem to me to
create additional drag.

I'm guessing that just the additional turning of the gears for hours on end
would, at some point, create additional wear on them. How much,
significant...I wouldn't hazard a guess.

When I do finally get retired and head to the S. Pac, I'll consider both,
and solar as well.

This has been a great discussion...thanks to all.
Kent
SM 243
Kristy

Hi all. can't agree about a wind generator being unusable in a decent wind and seaway. As I have said before our super wind is at the top of the mizzen and has been in constant use in all conditions of sea and wind. We never have had to consider it at any time, it just keeps on going. As to the drag of a propellor, we had a max prop on a previous boat, if we failed to feather it (ie left the shaft and propellor spinning free (no generator on it) there was a very noticable speed loss. we were racing that boat so we were very aware.
Regards
Danny
SM 299 Ocean Pearl
Mangonui
New Zealand

From: David Mackintosh <sv.highland.fling@...>
To: amelyachtowners@...
Sent: Wednesday, 20 July 2011 12:00 PM
Subject: Re: [Amel] Re: Maramu prop shaft alternator

I think you will find a wind generator is not really usable when sailing in
decent winds and seas as gyroscopic effects and precession all start to have
a serious effect.

You are correct of course water being denser than air it is much easier to
extract power from a water driven propeller. BUT i think you miss the point
- lets say a PSA producing 10/15 Amp takes 1.5 HP to drive  That HP has to
come from somewhere - the sails :-)  To get your say what 22 metric ton
Amel  up to hull speed is going to take say 80 HP so the losses assuming
they can be measured in a real live real time situation are going to be
insignificant really

Plus if you have 150/200 HP from your sails you have an excess of power and
since your Amel cant get up and plane - you have oodles of spare free HP to
drive your PSA.  Any time you have more power from your sails than that
needed to drive the boat at hull speed..there will be no actual loss of
performance when using the PSA.

Actual real time real life reports on the PAS performance say the losses are
insignificant - not really measurable.

Now lets look at the trasmission  designed to drive this 22MT boat with say
70 SHP...............do you really think you can damage that transmission in
any way by powering a 1.5 HP PSA with it?  I think NOT!!!

IF anyone wants to dump their PSA then please contact me i would love to
have it :-)

regards

David

On 20 July 2011 00:13, Dave_Benjamin <dave_benjamin@...> wrote:

**


I'm a bit confused about the comparison in losses between the PSA and a
wind generator. Water is far denser than air. The prop becomes a speed brake
of sort. I'm not a physicist but I'd wager that amp for amp the performance
loss with a wind generator is negligible compared to a PSA.

 

------------------------------------

Yahoo! Groups Links



[Non-text portions of this message have been removed]

I do feel we are missing the point here,  Its virtually free power with almost ZERO carbon foot print. Yes I am factoring in the costs of belts, manufacture of gearbox and pulley. I will continue to use my PSA rather than buy diesel.

Regards Deb



________________________________
From: David Wallace <svairops@...>
To: amelyachtowners@...
Sent: Tuesday, 19 July 2011, 6:36
Subject: RE: [Amel] Re: Maramu prop shaft alternator


A couple of things to think about:
• If a PSA is generating 20 amps @ 13 volts, that's 260 watts which is about 1/3 HP.  So you need a motive force equal to that level of drag to overcome it.  Hard to imagine that that level of drag would cost the boat 1/2 kt. 
• Also, it would seem to be no different if you were "using" 1/3 HP of motive force to generate the power with either a PSA or a wind generator, and I've never heard anyone say they were losing 1/2 kt because of a wind gen. 
• In any case, if your boat has a fixed prop, the prop/shaft/gearbox is already generating drag so the PSA would just be incremental on top of that.
• But we really need a marine architect to figure out the actual drag/HP required and tradeoffs.
Daves/v Air OpsMaramu #104

To: amelyachtowners@...
From: dave_benjamin@...
Date: Tue, 19 Jul 2011 03:15:47 +0000
Subject: [Amel] Re: Maramu prop shaft alternator






















 


   
     
     
      Capt Amel also used hank on sails for many years. In fact the original design of the Maramu was for hank on sails, not furling. So using this logic we could justify hank on sails.



Capt Amel made decisions based on the technology available at the time. What was a great thought in the 1980's is not necessarily the best choice today. While I would not necessarily scrap a PSA if I had one, I wouldn't be inclined to install it given the alternatives that produce reasonable amounts of power without slowing the boat by half a knot.



--- In amelyachtowners@..., Chris Smither <yachtakwaaba@...> wrote:

David - I agree. Capt Amel always thought through his equipment, and if he fitted a PSA you can bet your life he would have thought through the need for:

1. A lubrication system that works whether the prop is driven - either way, or idling

2. A hurth gearbox that can rotate freely in neutral when not under engine load.

On my santorin there was a notice - in french which said - when sailing NEVER select forward gear!

To stop the prop (fixed pitch) you select reverse and with a resounding "KLONK" the shaft stops rotating.

In 20 years and 58,000 sea miles I've done it twice........to clear lines around the prop

Mike & Chris

Akwaaba

SN027

________________________________

From: David Mackintosh <sv.highland.fling@...>

To: amelyachtowners@...

Sent: Saturday, July 16, 2011 3:07 AM

Subject: Re: [Amel] Re: Maramu prop shaft alternator

Come on get real - we have a gearbox/transmission designed for what (to

transmit 50 or so HP in Forward and Reverse) and you think you can damage it

by driving a small alternator  Please folks that suggestion is just so far

off the mark it makes me want to write some rather nasty comments.

For those with telepathic or cryptic powers WPAYO!!!

regards

David

On 15 July 2011 15:46, Joel Potter <jfpottercys@...> wrote:

**

When things are turning there is wear. The driveline is designed to,

primarily, transmit power in the other direction. My experiences using the

PSA on the Super Maramu caused a half Knot loss in speed compared to a

stopped and feathered Max or Autoprop.

Joel F. Potter

Cruising Yacht Specialist.

Amel's Sole Associate For America.

Sent from my iPhone.

Office: 954 462 5869

Cell: 954 812 2485

On Jul 15, 2011, at 10:19 AM, Pat <sailw32@...> wrote:

Joel, There has been postings suggesting wear to the drive train

associated with the prop freewheeling while the PSA is engaged. Can you

answer a couple questions?

First, are the gears being lubricated while freewheeling and do you

believe there is an amount of wear occurring to be concerned about? Second,

while sailing and the prop spinning, can the transmission be damaged putting

it reverse? I really like the PSA, I went sailing last night for about 5

hrs. in 15 knts. and came in with higher voltage than when I left my

mooring. One last comment, people mention losing half a knt. while the PSA

is engaged. I have never seen that kind of speed loss, while you have to

lose some speed, it has to be a fraction of a knt., for I cannot see it

reflected on the SOG., any thoughts on speed loss?

Thanks,

Pat SM 123

PS. Thanks, for your help in regards to my re-rig this past spring, took

your suggestion painted entire mast, lots of work but looks new.

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

 

[Non-text portions of this message have been removed]

------------------------------------

Yahoo! Groups Links

[Non-text portions of this message have been removed]

   
   

   
   






 
                       





------------------------------------

Yahoo! Groups Links



[Non-text portions of this message have been removed]

Just to add to this interesting discussion,  746watts  equals 1 Horse power.    So lets say 20 amps  x 14.2v   = 284  Watts    double it for losses.  568 Watts.  Now  568/746  = 0.76 Hp.  A lot less than has been suggested  and still  free power.

Regards  Deb



________________________________
From: Dave_Benjamin <dave_benjamin@...>
To: amelyachtowners@...
Sent: Wednesday, 20 July 2011, 0:13
Subject: [Amel] Re: Maramu prop shaft alternator


 
I'm a bit confused about the comparison in losses between the PSA and a wind generator. Water is far denser than air. The prop becomes a speed brake of sort. I'm not a physicist but I'd wager that amp for amp the performance loss with a wind generator is negligible compared to a PSA.




[Non-text portions of this message have been removed]

Kent, I just want to say, I agree with you . There is always going to be
subjects that people do not agree on, that should be expected and welcomed,
however posts should always be civil and respectful. I also want to thank
everyone that takes the time to offer their views, these are complex boats for a
dimwit to understand, and I find this forum very helpful. Thanks, Pat SM
123

Hi Kent

You dont need a fixed prop you can use a MaxProp and 'force' it to stay open
so you can have regeneration when you want it and no prop drag when you dont

Most people dont know that you can have the MaxProp stay open to drive a PSA

IF you have a PSA then use it IF you dont have a PSA Wind and Solar
generation then the CBA for Solar PSA and Wind is very hard to justify vis a
vis burning diesel....................IF you are limited in your ability to
purchase diesel (you are going to be sailing well off the beaten track)
then that will need serious consideration and may perhaps override the CBA.

I wonder if Bill would chime in here re CBA of wind/solar vis a vis burning
diesel.

regards

David

On 20 July 2011 01:21, Kent Robertson <karkauai@...> wrote:

**


Do those of you with wind generators use them when at sea? Do you see any
problems with performance as the boat moves with the seas? I'm not
experienced with either wind or PSA generators, but with wind it seems to me
the wind is driving the wind generator essentially independently of what
it's doing to the sails, unless the wind is coming from astern and
interrupting the flow of air on the sails. If you're dragging a fixed prop
it wouldn't seem to make much of a difference using a PSA, but if you're
using a feathering prop as many are, the turning prop would seem to me to
create additional drag.

I'm guessing that just the additional turning of the gears for hours on
end would, at some point, create additional wear on them. How much,
significant...I wouldn't hazard a guess.

When I do finally get retired and head to the S. Pac, I'll consider both,
and solar as well.

This has been a great discussion...thanks to all.
Kent
SM 243

Kristy

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