jeff, are you sure of that 25 to 35 pound figure at 7 knots? I recall 170# at
5 knots.

35# at 7 knots is only about 3/4 hp. not worth thinking about.

If you insist on calling the Autoprop "feathering" then you have to admit its
a
pretty poor one, having 5 to 10 times the drag of other feathering props.
For
example, in the MIT/Practical Sailor test, at about 7 knots the Autoprop had
10
pounds of drag, while the 2 and 3 blade Maxprop feathering props had about 1
and
2 pounds respectively. The folding props were so low they weren't shown. 10
pounds of drag is pretty good, compared to the 25 to 35 pounds for many of
the
props in the test, but it isn't the same as feathering. The Autoprop has
some
interesting properties, like very good performance in reverse, if you rev it
up.


"Jim Richardson" wrote in message
...
On 04 Sep 2004 13:08:18 GMT,
JAXAshby wrote:
Then why did you post a definition of feathering, which fit the
autoprop?

it does not fit. not even close. and if you had not blown $2,200 on a
prop
hoping against hope you could make your boat *sail* faster you would know
the
difference.

Did the dealer tell you you could pass Island Packets and Westsail 32 if
you
bought an auto-prop?



I didn't buy one JAXAshby. I simply wanted to know what you meant by
calling it a non-feathering prop. Alas, I should have known better than
to expect rational discourse from you.

--
Jim Richardson http://www.eskimo.com/~warlock
'Windows' really does make a fine swear word, representing all that's
taboo and awful - just like '****', '****', etc."
-- Mark Hughes, sdm

"JAXAshby" wrote in message
...
....
keep in mind that props don't drag all that much anyway. according to the MIT
data, even a fixed 3 blade only pulled 170# on a boat at 5 knots, or about
the
equivelent of 2-1/2 hp.


That's not much drag??? That's roughly the drag from a 25 knot breeze! Are
you saying that this would have no affect on boat speed?

Are you claiming that a having a 2.5 hp engine pulling backwards would have
little affect on speed? At the low RPMs many boats use to go 5 knots, they only
use 10 to 12 hp to go forward

I'm reading from the Jan 1,1995 article "MIT Propeller Test - Part 2." The
Michigan Wheel 3-blade had about 70 pounds drag at 8 knots. This is a huge
amount of drag, costing maybe 10% of boat speed. The earlier article (Oct 1,
'93) had the same numbers plus a discussion on how much speed this would cost.
They predicted 1/3 of a knot improvement, averaged over a wide variety of
conditions, for a 25 foot boat when removing a 3 blade prop.

I'd agree with some of your conclusions, especially that a folding prop is
perhaps not useful for the OP's Westsail. Since a 2-blade fixed can be lined up
in the aperture to minimize drag, there's little reason to sacrifice reverse
capability with a folder. I can't imagine trying to "crash stop" a Westsail
with a poor performing prop.

However, this is not true for a lot of boats. Many fin keel boats have the prop
too far from the keel to benefit from lining it up. Boats with Saildrives don't
have that option. Light weight boats that rely on low drag would be affected
worse by a high drag prop. And catamarans, with two props would have double the
drag with fixed props.




"JAXAshby" wrote in message
...
jeff, are you sure of that 25 to 35 pound figure at 7 knots? I recall 170# at
5 knots.

35# at 7 knots is only about 3/4 hp. not worth thinking about.

If you insist on calling the Autoprop "feathering" then you have to admit its
a
pretty poor one, having 5 to 10 times the drag of other feathering props.
For
example, in the MIT/Practical Sailor test, at about 7 knots the Autoprop had
10
pounds of drag, while the 2 and 3 blade Maxprop feathering props had about 1
and
2 pounds respectively. The folding props were so low they weren't shown. 10
pounds of drag is pretty good, compared to the 25 to 35 pounds for many of
the
props in the test, but it isn't the same as feathering. The Autoprop has
some
interesting properties, like very good performance in reverse, if you rev it
up.


"Jim Richardson" wrote in message
...
On 04 Sep 2004 13:08:18 GMT,
JAXAshby wrote:
Then why did you post a definition of feathering, which fit the
autoprop?

it does not fit. not even close. and if you had not blown $2,200 on a
prop
hoping against hope you could make your boat *sail* faster you would know
the
difference.

Did the dealer tell you you could pass Island Packets and Westsail 32 if
you
bought an auto-prop?



I didn't buy one JAXAshby. I simply wanted to know what you meant by
calling it a non-feathering prop. Alas, I should have known better than
to expect rational discourse from you.

--
Jim Richardson http://www.eskimo.com/~warlock
'Windows' really does make a fine swear word, representing all that's
taboo and awful - just like '****', '****', etc."
-- Mark Hughes, sdm

ubject: What are the pros and cons of a folding prop?
From: "Jeff Morris"

If you insist on calling the Autoprop "feathering" then you have to admit its
a
pretty poor one, having 5 to 10 times the drag of other feathering props.
For
example, in the MIT/Practical Sailor test, at about 7 knots the Autoprop had
10
pounds of drag, while the 2 and 3 blade Maxprop feathering props had about 1
and
2 pounds respectively. The folding props were so low they weren't shown. 10
pounds of drag is pretty good, compared to the 25 to 35 pounds for many of
the
props in the test, but it isn't the same as feathering. The Autoprop has
some
interesting properties, like very good performance in reverse, if you rev

From this, and looking at diagrams of both the "maxprop" and "autoprop", it
appears that both designs can rightly call themselves "feathering".
However, it appears that the design of the hub of the autoprop is such that it
still creates a marked amount of drag which has little to do with the
shape/curvature of the blades.
Agree/disagree/comments?

Shen

On 04 Sep 2004 21:19:13 GMT,
JAXAshby wrote:
jim, the term "feathering" means to twist the blades into a streamline
position with a teeny, tiny, itzy, bitsy, little, small fraction of
the drag presented by blades in operating under power position.

understand now?



yeah, the autoprop turns it's blades, to be parallel to the axis of the
shaft, resulting in less drag than in the fwd or reverse direction,.
How is that not feathering?



--
Jim Richardson http://www.eskimo.com/~warlock
Go the extra mile. It makes your boss look like an
incompetent slacker.

On Sat, 4 Sep 2004 17:40:54 -0400,
Jeff Morris wrote:
If you insist on calling the Autoprop "feathering" then you have to
admit its a pretty poor one, having 5 to 10 times the drag of other
feathering props. For example, in the MIT/Practical Sailor test, at
about 7 knots the Autoprop had 10 pounds of drag, while the 2 and 3
blade Maxprop feathering props had about 1 and 2 pounds respectively.
The folding props were so low they weren't shown. 10 pounds of drag
is pretty good, compared to the 25 to 35 pounds for many of the props
in the test, but it isn't the same as feathering. The Autoprop has
some interesting properties, like very good performance in reverse, if
you rev it up.




I agree that it's not as low drag as the max prop, it also has way too
much rotating mass for my likes, which is one reason I wouldn't buy one.
But the mechanism is pretty simple, and the thing has a fairly
significant reduction in drag, over a fixed prop yes?

I do find JAXAshby's posts amusing however. although I suppose it's rude
to toy with the retarded kid.

"Jim Richardson" wrote in message
...
On 04 Sep 2004 13:08:18 GMT,
JAXAshby wrote:
Then why did you post a definition of feathering, which fit the
autoprop?

it does not fit. not even close. and if you had not blown $2,200 on a prop
hoping against hope you could make your boat *sail* faster you would know
the
difference.

Did the dealer tell you you could pass Island Packets and Westsail 32 if you
bought an auto-prop?



I didn't buy one JAXAshby. I simply wanted to know what you meant by
calling it a non-feathering prop. Alas, I should have known better than
to expect rational discourse from you.

--
Jim Richardson http://www.eskimo.com/~warlock
'Windows' really does make a fine swear word, representing all that's
taboo and awful - just like '****', '****', etc."
-- Mark Hughes, sdm




--
Jim Richardson http://www.eskimo.com/~warlock
Sin lies only in hurting other people unnecessarily. All other 'sins' are
invented nonsense. (Hurting yourself is not sinful - just stupid.)
-- Lazarus Long

On 04 Sep 2004 23:25:53 GMT,
Shen44 wrote:
ubject: What are the pros and cons of a folding prop?
From: "Jeff Morris"

If you insist on calling the Autoprop "feathering" then you have to admit its
a
pretty poor one, having 5 to 10 times the drag of other feathering props.
For
example, in the MIT/Practical Sailor test, at about 7 knots the Autoprop had
10
pounds of drag, while the 2 and 3 blade Maxprop feathering props had about 1
and
2 pounds respectively. The folding props were so low they weren't shown. 10
pounds of drag is pretty good, compared to the 25 to 35 pounds for many of
the
props in the test, but it isn't the same as feathering. The Autoprop has
some
interesting properties, like very good performance in reverse, if you rev

From this, and looking at diagrams of both the "maxprop" and "autoprop", it
appears that both designs can rightly call themselves "feathering".
However, it appears that the design of the hub of the autoprop is such that it
still creates a marked amount of drag which has little to do with the
shape/curvature of the blades.
Agree/disagree/comments?

Shen


Sounds about right to me, the autprop looks like it would produce
significantly more drag than the Max prop to me, and that both, would
produce less drag than a fixed. Since I think the autoprop is about the
same $$ as the Max prop, I'd go for the Max, unless there was some real
good reason otherwise. Maintenance maybe? is the Max prop a lot more
work to maintain?

--
Jim Richardson http://www.eskimo.com/~warlock
"`If there's anything more important than my ego around, I
want it caught and shot now.'"
-- Zaphod

jeffies, a boat under sail has one hell of a lot more drag than a boat motoring
in a flat calm.

also, keep in mind that the boat under discussion is a Westsail 32, a boat
usually having a minimum of 30 hp installed, and often 40+ hp.

A Westsail 32 with a 10 to 12 hp engine installed is unmarketable. One would
need one hell of a lot patience to wait for wind and tide before setting off.

keep in mind that props don't drag all that much anyway. according to the
MIT
data, even a fixed 3 blade only pulled 170# on a boat at 5 knots, or about
the
equivelent of 2-1/2 hp.


That's not much drag??? That's roughly the drag from a 25 knot breeze!
Are
you saying that this would have no affect on boat speed?

Are you claiming that a having a 2.5 hp engine pulling backwards would have
little affect on speed? At the low RPMs many boats use to go 5 knots, they
only
use 10 to 12 hp to go forward

10% of max boat speed = 1/3 knot??

That one heap slow mutha boat.

I'm reading from the Jan 1,1995 article "MIT Propeller Test - Part 2." The
Michigan Wheel 3-blade had about 70 pounds drag at 8 knots. This is a huge
amount of drag, costing maybe 10% of boat speed. The earlier article (Oct 1,
'93) had the same numbers plus a discussion on how much speed this would
cost.
They predicted 1/3 of a knot improvement, averaged over a wide variety of
conditions, for a 25 foot boat when removing a 3 blade prop.

I'd agree with some of your conclusions, especially that a folding prop is
perhaps not useful for the OP's Westsail. Since a 2-blade fixed can be lined
up
in the aperture to minimize drag, there's little reason to sacrifice reverse
capability with a folder. I can't imagine trying to "crash stop" a Westsail
with a poor performing prop.

However, this is not true for a lot of boats. Many fin keel boats have the
prop
too far from the keel to benefit from lining it up. Boats with Saildrives
don't
have that option. Light weight boats that rely on low drag would be affected
worse by a high drag prop. And catamarans, with two props would have double
the
drag with fixed props.




"JAXAshby" wrote in message
...
jeff, are you sure of that 25 to 35 pound figure at 7 knots? I recall 170#
at
5 knots.

35# at 7 knots is only about 3/4 hp. not worth thinking about.

If you insist on calling the Autoprop "feathering" then you have to admit
its
a
pretty poor one, having 5 to 10 times the drag of other feathering props.
For
example, in the MIT/Practical Sailor test, at about 7 knots the Autoprop
had
10
pounds of drag, while the 2 and 3 blade Maxprop feathering props had about
1
and
2 pounds respectively. The folding props were so low they weren't shown.
10
pounds of drag is pretty good, compared to the 25 to 35 pounds for many of
the
props in the test, but it isn't the same as feathering. The Autoprop has
some
interesting properties, like very good performance in reverse, if you rev
it
up.


"Jim Richardson" wrote in message
...
On 04 Sep 2004 13:08:18 GMT,
JAXAshby wrote:
Then why did you post a definition of feathering, which fit the
autoprop?

it does not fit. not even close. and if you had not blown $2,200 on
a
prop
hoping against hope you could make your boat *sail* faster you would
know
the
difference.

Did the dealer tell you you could pass Island Packets and Westsail 32
if
you
bought an auto-prop?



I didn't buy one JAXAshby. I simply wanted to know what you meant by
calling it a non-feathering prop. Alas, I should have known better than
to expect rational discourse from you.

--
Jim Richardson http://www.eskimo.com/~warlock
'Windows' really does make a fine swear word, representing all that's
taboo and awful - just like '****', '****', etc."
-- Mark Hughes, sdm

I explained it three times already, jimmy. ask your homeroom teacher.

jim, the term "feathering" means to twist the blades into a streamline
position with a teeny, tiny, itzy, bitsy, little, small fraction of
the drag presented by blades in operating under power position.

understand now?



yeah, the autoprop turns it's blades, to be parallel to the axis of the
shaft, resulting in less drag than in the fwd or reverse direction,.
How is that not feathering?



--
Jim Richardson http://www.eskimo.com/~warlock
Go the extra mile. It makes your boss look like an
incompetent slacker.