Removing 3 bladed prop on an Alberg 35
 

I bought an Indigo 3 bladed prop last week for my Alberg 35 with the
original Atomic 4, as the existing prop succumbed to electrolysis

I went down to the boat yesterday, worried that I might not be able to
loosen the old hub's grip on the shaft. It was also a 3 bladed prop.
That was actually easy after about 5 minutes with a map gas torch.

I seem to have only about an inch of space between the end of the prop
shaft and the rudder (post). The hub is about 2-2,5 inches thick. I've
tried swinging the rudder from stop to stop, but don't seem to be able
to find an angle that will allow the old prop to come off, or, for that
matter, a new one to go on.

Others must have encountered this problem and found a solution.....

At this juncture it seems to me that I either have to dismount the
rudder to gain an extra inch or so, or I have to unmount the engine and
pull the prop shaft forward a couple of inches (if that's even possible )

I am hoping that I missed something perfectly obvious as I was working
late and was tired.... any help appreciated.

Thanks,

Jonathan Wye


--
I am building my daughter an Argie 10 sailing dinghy, check it out:
http://home.comcast.net/~jonsailr

Removing 3 bladed prop on an Alberg 35
 

On Mon, 13 Aug 2007 23:00:14 -0400, Jonathan W
wrote:

I bought an Indigo 3 bladed prop last week for my Alberg 35 with the
original Atomic 4, as the existing prop succumbed to electrolysis

I went down to the boat yesterday, worried that I might not be able to
loosen the old hub's grip on the shaft. It was also a 3 bladed prop.
That was actually easy after about 5 minutes with a map gas torch.

I seem to have only about an inch of space between the end of the prop
shaft and the rudder (post). The hub is about 2-2,5 inches thick. I've
tried swinging the rudder from stop to stop, but don't seem to be able
to find an angle that will allow the old prop to come off, or, for that
matter, a new one to go on.

Others must have encountered this problem and found a solution.....

At this juncture it seems to me that I either have to dismount the
rudder to gain an extra inch or so, or I have to unmount the engine and
pull the prop shaft forward a couple of inches (if that's even possible )

I am hoping that I missed something perfectly obvious as I was working
late and was tired.... any help appreciated.

Thanks,

Jonathan Wye


Sorry to say but there are only two ways to get more room, both of
which you've mentioned. I believe most people would prefer to pull the
rudder..

I'm not familiar with an alberg 35 rudder but if you are taking it off
is thee a possibility you could have it modified with a little larger
cut out in case you want to remove things sometime in the future?

There is an Alberg user's group - google "alberg 35" but they didn't
have anything to say about removing a propeller. Apparently not a
popular pass time.


Bruce in Bangkok
(brucepaigeATgmailDOTcom)

Removing 3 bladed prop on an Alberg 35
 

It's called poor engineering and it is unfortunately, very common. The
engine and propshaft should be offset to allow shaft removal without the
rudder and there should be adequate clearance between the rudder and shaft
for removing the prop. Additionally, there should be at 2 inches clearance
between the outer diameter of the prop and the bottom of the boat to prevent
pounding from prop turbulence, but too often these things are not done for
cost savings.

You may be able to remove the coupling from the gear box and gain a bit of
clearance as well, but pulling the rudder has the advantage of being able to
use a prop puller as well.
Steve

"Jonathan W" wrote in message
. ..
I bought an Indigo 3 bladed prop last week for my Alberg 35 with the
original Atomic 4, as the existing prop succumbed to electrolysis

I went down to the boat yesterday, worried that I might not be able to
loosen the old hub's grip on the shaft. It was also a 3 bladed prop. That
was actually easy after about 5 minutes with a map gas torch.

I seem to have only about an inch of space between the end of the prop
shaft and the rudder (post). The hub is about 2-2,5 inches thick. I've
tried swinging the rudder from stop to stop, but don't seem to be able to
find an angle that will allow the old prop to come off, or, for that
matter, a new one to go on.

Others must have encountered this problem and found a solution.....

At this juncture it seems to me that I either have to dismount the rudder
to gain an extra inch or so, or I have to unmount the engine and pull the
prop shaft forward a couple of inches (if that's even possible )

I am hoping that I missed something perfectly obvious as I was working
late and was tired.... any help appreciated.

Thanks,

Jonathan Wye


--
I am building my daughter an Argie 10 sailing dinghy, check it out:
http://home.comcast.net/~jonsailr

Removing 3 bladed prop on an Alberg 35
 

On Aug 14, 4:44 am, "Steve Lusardi" wrote:
It's called poor engineering and it is unfortunately, very common. The
engine and propshaft should be offset to allow shaft removal without the
rudder and there should be adequate clearance between the rudder and shaft
for removing the prop. Additionally, there should be at 2 inches clearance
between the outer diameter of the prop and the bottom of the boat to prevent
pounding from prop turbulence, but too often these things are not done for
cost savings.

You may be able to remove the coupling from the gear box and gain a bit of
clearance as well, but pulling the rudder has the advantage of being able to
use a prop puller as well.
Steve

"Jonathan W" wrote in message

. ..

I bought an Indigo 3 bladed prop last week for my Alberg 35 with the
original Atomic 4, as the existing prop succumbed to electrolysis

I went down to the boat yesterday, worried that I might not be able to
loosen the old hub's grip on the shaft. It was also a 3 bladed prop. That
was actually easy after about 5 minutes with a map gas torch.

I seem to have only about an inch of space between the end of the prop
shaft and the rudder (post). The hub is about 2-2,5 inches thick. I've
tried swinging the rudder from stop to stop, but don't seem to be able to
find an angle that will allow the old prop to come off, or, for that
matter, a new one to go on.

Others must have encountered this problem and found a solution.....

At this juncture it seems to me that I either have to dismount the rudder
to gain an extra inch or so, or I have to unmount the engine and pull the
prop shaft forward a couple of inches (if that's even possible )

I am hoping that I missed something perfectly obvious as I was working
late and was tired.... any help appreciated.

Thanks,

Jonathan Wye

--
I am building my daughter an Argie 10 sailing dinghy, check it out:
http://home.comcast.net/~jonsailr

Cut the prop shaft in the boat. Take out a 2" long section. Take off
prop. When re-installing, use a sliding coupler to join the two
pieces. This assumes you even have enough room to do this cutting.

Removing 3 bladed prop on an Alberg 35
 

"Frogwatch" wrote

Cut the prop shaft in the boat. Take out a 2" long section. Take off
prop. When re-installing, use a sliding coupler to join the two
pieces. This assumes you even have enough room to do this cutting.


Woah! This is up there with some of the worst advice I've encountered on
this newsgroup.

--
Roger Long

Removing 3 bladed prop on an Alberg 35
 

"Roger Long" wrote in message
...

"Frogwatch" wrote

Cut the prop shaft in the boat. Take out a 2" long section. Take off
prop. When re-installing, use a sliding coupler to join the two
pieces. This assumes you even have enough room to do this cutting.


Woah! This is up there with some of the worst advice I've encountered on
this newsgroup.

--
Roger Long


Ya, I kinda cringed when I read it. Alignment questions aside, that would
have to be one strong coupler.

Removing 3 bladed prop on an Alberg 35
 

On Tue, 14 Aug 2007 09:57:42 -0400, "Roger Long"
wrote:


"Frogwatch" wrote

Cut the prop shaft in the boat. Take out a 2" long section. Take off
prop. When re-installing, use a sliding coupler to join the two
pieces. This assumes you even have enough room to do this cutting.


Woah! This is up there with some of the worst advice I've encountered on
this newsgroup.

There isn't any room to do it anyway. The shaft nearly hits the rudder
in the rear and there is only a couple of inches between the engine
coupling and the packing gland.

Unless you wanted an Alberg 33 with the open back cockpit for racing
:-)




Bruce in Bangkok
(brucepaigeATgmailDOTcom)

Removing 3 bladed prop on an Alberg 35
 

What limits/prevents the rudder from swinging to the side.
If it is steering linkage, that can be unhooked to allow more movement,
If it is the mechanical attachment of the rudder itself, you're toast.
Who installed the last one and could you talk to them?
Gordon

Removing 3 bladed prop on an Alberg 35
 

I once chartered a Hunter 37 (IMS) with just this arrangement. And it did in
fact come loose, luckly with the coupling attached to the prop side so it
didn't leave the boat.


"Roger Long" wrote in message
...

"Frogwatch" wrote

Cut the prop shaft in the boat. Take out a 2" long section. Take off
prop. When re-installing, use a sliding coupler to join the two
pieces. This assumes you even have enough room to do this cutting.


Woah! This is up there with some of the worst advice I've encountered on
this newsgroup.

--
Roger Long

Removing 3 bladed prop on an Alberg 35
 

Jonathan,
This is a very common issue with the long keel boats that have the
propeller in an appature.
It is a toss up. If the heel casting unscrews, then dropping the rudder
is really pretty simple. Take all the head fitting off the rudder,
unscrew (2 as I recall) the big screws that hold on the heal casting and
down it comes.

I actual fact, if you keep track of the shims, pulling a U4 forward an
inch and an half is usually just about as hard. The problem if there is
one is the exhaust pipe. The hoses and wires will usually pull that
far, but if the muffler can't be moved with the engine (some can) then
you don't want to mess with that during the season. It may take you out
of commission for longer than it is worth.

Matt Colie
Lifelong Waterman, Licensed Mariner and Perpetual Sailor

Jonathan W wrote:
I bought an Indigo 3 bladed prop last week for my Alberg 35 with the
original Atomic 4, as the existing prop succumbed to electrolysis

I went down to the boat yesterday, worried that I might not be able to
loosen the old hub's grip on the shaft. It was also a 3 bladed prop.
That was actually easy after about 5 minutes with a map gas torch.

I seem to have only about an inch of space between the end of the prop
shaft and the rudder (post). The hub is about 2-2,5 inches thick. I've
tried swinging the rudder from stop to stop, but don't seem to be able
to find an angle that will allow the old prop to come off, or, for that
matter, a new one to go on.

Others must have encountered this problem and found a solution.....

At this juncture it seems to me that I either have to dismount the
rudder to gain an extra inch or so, or I have to unmount the engine and
pull the prop shaft forward a couple of inches (if that's even possible )

I am hoping that I missed something perfectly obvious as I was working
late and was tired.... any help appreciated.

Thanks,

Jonathan Wye

Removing 3 bladed prop on an Alberg 35
 

On Tue, 14 Aug 2007 13:44:42 -0400, Matt Colie
wrote:

Jonathan,
This is a very common issue with the long keel boats that have the
propeller in an appature.
It is a toss up. If the heel casting unscrews, then dropping the rudder
is really pretty simple. Take all the head fitting off the rudder,
unscrew (2 as I recall) the big screws that hold on the heal casting and
down it comes.

I actual fact, if you keep track of the shims, pulling a U4 forward an
inch and an half is usually just about as hard. The problem if there is
one is the exhaust pipe. The hoses and wires will usually pull that
far, but if the muffler can't be moved with the engine (some can) then
you don't want to mess with that during the season. It may take you out
of commission for longer than it is worth.

Matt Colie
Lifelong Waterman, Licensed Mariner and Perpetual Sailor

Jonathan W wrote:
I bought an Indigo 3 bladed prop last week for my Alberg 35 with the
original Atomic 4, as the existing prop succumbed to electrolysis

I went down to the boat yesterday, worried that I might not be able to
loosen the old hub's grip on the shaft. It was also a 3 bladed prop.
That was actually easy after about 5 minutes with a map gas torch.

I seem to have only about an inch of space between the end of the prop
shaft and the rudder (post). The hub is about 2-2,5 inches thick. I've
tried swinging the rudder from stop to stop, but don't seem to be able
to find an angle that will allow the old prop to come off, or, for that
matter, a new one to go on.

Others must have encountered this problem and found a solution.....

At this juncture it seems to me that I either have to dismount the
rudder to gain an extra inch or so, or I have to unmount the engine and
pull the prop shaft forward a couple of inches (if that's even possible )

I am hoping that I missed something perfectly obvious as I was working
late and was tired.... any help appreciated.

Thanks,

Jonathan Wye


There is an Alberg group - google for it -- that has an article about
converting to wheel steering that has a pretty comprehensive section
on removing the rudder.


Bruce in Bangkok
(brucepaigeATgmailDOTcom)

Removing 3 bladed prop on an Alberg 35
 

On Mon, 13 Aug 2007 23:00:14 -0400, Jonathan W
wrote:

I seem to have only about an inch of space between the end of the prop
shaft and the rudder (post). The hub is about 2-2,5 inches thick. I've
tried swinging the rudder from stop to stop, but don't seem to be able
to find an angle that will allow the old prop to come off, or, for that
matter, a new one to go on.....
At this juncture it seems to me that I either have to dismount the
rudder to gain an extra inch or so, or I have to unmount the engine and
pull the prop shaft forward a couple of inches (if that's even possible )

I am hoping that I missed something perfectly obvious as I was working
late and was tired.... any help appreciated.
...
Jonathan Wye

There *IS* the Medieval option. Accomplished with a Sawzall upon the
defenseless rudder. Then made good with epoxy/glass, complete with
two inch set back for NEXT time :-)

Brian Whatcott Altus OK.

Removing 3 bladed prop on an Alberg 35
 

On Wed, 15 Aug 2007 02:45:36 GMT, Brian Whatcott
wrote:

On Mon, 13 Aug 2007 23:00:14 -0400, Jonathan W
wrote:

I seem to have only about an inch of space between the end of the prop
shaft and the rudder (post). The hub is about 2-2,5 inches thick. I've
tried swinging the rudder from stop to stop, but don't seem to be able
to find an angle that will allow the old prop to come off, or, for that
matter, a new one to go on.....
At this juncture it seems to me that I either have to dismount the
rudder to gain an extra inch or so, or I have to unmount the engine and
pull the prop shaft forward a couple of inches (if that's even possible )

I am hoping that I missed something perfectly obvious as I was working
late and was tired.... any help appreciated.
..
Jonathan Wye

There *IS* the Medieval option. Accomplished with a Sawzall upon the
defenseless rudder. Then made good with epoxy/glass, complete with
two inch set back for NEXT time :-)

Brian Whatcott Altus OK.


That is a point. The User's group listing says that the rudder is
solid mahogany....
Bruce in Bangkok
(brucepaigeATgmailDOTcom)

Removing 3 bladed prop on an Alberg 35
 

On Wed, 15 Aug 2007 15:40:14 +0700, wrote:

There *IS* the Medieval option. Accomplished with a Sawzall upon the
defenseless rudder. Then made good with epoxy/glass, complete with
two inch set back for NEXT time :-)
Got to be the way to go. You bust a corroded exhaust system and it
will be a major pain. Leave the engine alone.
There are a zillion powerboats that take a chain saw to get the
engines out. I think you can usually remove something like an A-4
without doing that. I have a chain saw and a sawzall. And an open
boat. And you can drill out the rivets with those aluminum hulls. Same
as aircraft repair.

Casady

Removing 3 bladed prop on an Alberg 35
 

On Aug 15, 4:40 am, wrote:
On Wed, 15 Aug 2007 02:45:36 GMT, Brian Whatcott



wrote:
On Mon, 13 Aug 2007 23:00:14 -0400, Jonathan W
wrote:

I seem to have only about an inch of space between the end of the prop
shaft and the rudder (post). The hub is about 2-2,5 inches thick. I've
tried swinging the rudder from stop to stop, but don't seem to be able
to find an angle that will allow the old prop to come off, or, for that
matter, a new one to go on.....
At this juncture it seems to me that I either have to dismount the
rudder to gain an extra inch or so, or I have to unmount the engine and
pull the prop shaft forward a couple of inches (if that's even possible )

I am hoping that I missed something perfectly obvious as I was working
late and was tired.... any help appreciated.
..
Jonathan Wye

There *IS* the Medieval option. Accomplished with a Sawzall upon the
defenseless rudder. Then made good with epoxy/glass, complete with
two inch set back for NEXT time :-)

Brian Whatcott Altus OK.

That is a point. The User's group listing says that the rudder is
solid mahogany....
Bruce in Bangkok
(brucepaigeATgmailDOTcom)

I will defend my suggestion although it sounds impractical for the
Alberg. A coupler properly made, probably from SS about 1" ID larger
than the shaft with deep holes drilled and then milled to size will be
as well balanced as the original. A few barnacles on a prop would
produce a far greater imbalance.
I have been amazed at how my 3 bladed prop does not shake even though
it gets covered with barnacles. I hit a mast from a dismasted Laser
this past year and made a huge ding in one blade and it still turns
smoothly. This causes me to believe that it is alignment, not balance
that is most critical and a well made coupler would maintain that
alignment. Besides, you can always re-align the shaft (fairly easy on
my S2).

Removing 3 bladed prop on an Alberg 35
 

On Thu, 16 Aug 2007 09:59:09 -0700, Frogwatch
wrote:


There *IS* the Medieval option. Accomplished with a Sawzall upon the
defenseless rudder. Then made good with epoxy/glass, complete with
two inch set back for NEXT time :-)

Brian Whatcott Altus OK.

That is a point. The User's group listing says that the rudder is
solid mahogany....
Bruce in Bangkok
(brucepaigeATgmailDOTcom)

I will defend my suggestion although it sounds impractical for the
Alberg. A coupler properly made, probably from SS about 1" ID larger
than the shaft with deep holes drilled and then milled to size will be
as well balanced as the original.

If what you want is to get in the water, thirty minutes with a rasp
and sandpaper might do it. No sawzall needed. Or is it covered with
glass?

Casady

Removing 3 bladed prop on an Alberg 35
 

On Thu, 16 Aug 2007 09:59:09 -0700, Frogwatch
wrote:

I will defend my suggestion although it sounds impractical for the
Alberg. A coupler properly made, probably from SS about 1" ID larger
than the shaft with deep holes drilled and then milled to size will be
as well balanced as the original. A few barnacles on a prop would
produce a far greater imbalance.
I have been amazed at how my 3 bladed prop does not shake even though
it gets covered with barnacles. I hit a mast from a dismasted Laser
this past year and made a huge ding in one blade and it still turns
smoothly. This causes me to believe that it is alignment, not balance
that is most critical and a well made coupler would maintain that
alignment. Besides, you can always re-align the shaft (fairly easy on
my S2).


Here's a little engineering insight. If a drive shaft is lightened
by drilling out an axial hole whose diameter is one half the outer
diameter - the shaft's strength in torque is reduced by 5% and its
weight is reduced by 25% This is important in aircraft
construction.

So as applied to cutting and shutting a propellor shaft, if its
diameter is x, and it is cut then bridged with a coupler,
the coupler's diameter ought to be just over twice the shaft's
diameter, to bridge across the gap. As to passing the torque into
and out of the coupler - the ideal connection is splines, the more the
merrier, within reason. But this is unlikely to be an option.
Another option, much simpler to arrange, is two well-fitted bolt holes
at right angles to each other, at one shaft diameter back from the
cut, and the other at two diameters back if possible. This is likely
to be weaker than the original torque capability.
There is another option, which will be familiar to you from
examining an old style (English) bike pedal crank.
A flat is worked on the shaft, and the pedal crank has a hole
to pass the shaft. But it also has a hole at right angles to the shaft
through which a cotter bolt with a tapered flat passes to bear on the
main shaft's flat. The cotter, when bolted tight, eliminates slippng
between the two pieces, so a wear point is eliminated.
If an eccentric hole can be drilled in the coupler, so a cotter bolt
can bear on the shaft, it would stop relative motion.
But there are many other ways you could concieve of connecting a shaft
into and out of a coupler, I'm sure.

Brian Whatcott Altus OK

Removing 3 bladed prop on an Alberg 35
 

On Thu, 16 Aug 2007 20:01:29 GMT, (Richard
Casady) wrote:

A coupler properly made, probably from SS about 1" ID larger
than the shaft
Surely you meant OD. Makes more sense that way.
Casady

Removing 3 bladed prop on an Alberg 35
 

On Fri, 17 Aug 2007 02:13:06 GMT, Brian Whatcott
wrote:

There is another option, which will be familiar to you from
examining an old style (English) bike pedal crank.

I had one like that, back in 1960. Loathed those cotters. And they
were tacky. Oh, so British.
Then there was the cotterless cranks with insufficient room for a
standard bolt. Head was too big. I got one from the Datsun dealer that
fit.

Casady

Removing 3 bladed prop on an Alberg 35
 

On Fri, 17 Aug 2007 02:13:06 GMT, Brian Whatcott
wrote:

On Thu, 16 Aug 2007 09:59:09 -0700, Frogwatch
wrote:

I will defend my suggestion although it sounds impractical for the
Alberg. A coupler properly made, probably from SS about 1" ID larger
than the shaft with deep holes drilled and then milled to size will be
as well balanced as the original. A few barnacles on a prop would
produce a far greater imbalance.
I have been amazed at how my 3 bladed prop does not shake even though
it gets covered with barnacles. I hit a mast from a dismasted Laser
this past year and made a huge ding in one blade and it still turns
smoothly. This causes me to believe that it is alignment, not balance
that is most critical and a well made coupler would maintain that
alignment. Besides, you can always re-align the shaft (fairly easy on
my S2).


Here's a little engineering insight. If a drive shaft is lightened
by drilling out an axial hole whose diameter is one half the outer
diameter - the shaft's strength in torque is reduced by 5% and its
weight is reduced by 25% This is important in aircraft
construction.

So as applied to cutting and shutting a propellor shaft, if its
diameter is x, and it is cut then bridged with a coupler,
the coupler's diameter ought to be just over twice the shaft's
diameter, to bridge across the gap. As to passing the torque into
and out of the coupler - the ideal connection is splines, the more the
merrier, within reason. But this is unlikely to be an option.
Another option, much simpler to arrange, is two well-fitted bolt holes
at right angles to each other, at one shaft diameter back from the
cut, and the other at two diameters back if possible. This is likely
to be weaker than the original torque capability.
There is another option, which will be familiar to you from
examining an old style (English) bike pedal crank.
A flat is worked on the shaft, and the pedal crank has a hole
to pass the shaft. But it also has a hole at right angles to the shaft
through which a cotter bolt with a tapered flat passes to bear on the
main shaft's flat. The cotter, when bolted tight, eliminates slippng
between the two pieces, so a wear point is eliminated.
If an eccentric hole can be drilled in the coupler, so a cotter bolt
can bear on the shaft, it would stop relative motion.
But there are many other ways you could concieve of connecting a shaft
into and out of a coupler, I'm sure.

Brian Whatcott Altus OK


I think the point you are missing is that although a coupling may very
well cope with the torque there just isn't any room to fit a coupling
of the type you describe at either the propeller or the engine end.
One might possibly use a larger cutlass bearing running on the O.D. of
the coupling but that would just add complications to a system that
should be as sim0le as possible.

The most logical answer is(1) remove the rudder, or (2) saw the cutout
in the rudder larger.




Bruce in Bangkok
(brucepaigeATgmailDOTcom)

Removing 3 bladed prop on an Alberg 35
 

On Fri, 17 Aug 2007 18:26:31 +0700, wrote:

Here's a little engineering insight. If a drive shaft is lightened
by drilling out an axial hole whose diameter is one half the outer
diameter - the shaft's strength in torque is reduced by 5% and its
weight is reduced by 25% This is important in aircraft
construction.

Driveshafts are usually tubes and not rods. Always for cars and big
ships. It is only the smaller boats that lack the space.

Casady

Removing 3 bladed prop on an Alberg 35
 

Richard Casady wrote:

On Fri, 17 Aug 2007 18:26:31 +0700, wrote:

Here's a little engineering insight. If a drive shaft is lightened
by drilling out an axial hole whose diameter is one half the outer
diameter - the shaft's strength in torque is reduced by 5% and its
weight is reduced by 25% This is important in aircraft
construction.

Driveshafts are usually tubes and not rods. Always for cars and big
ships. It is only the smaller boats that lack the space.

Casady

uh what have you been taking?
drive shafts on cars are tubes may be on other things; i have only seen one
driveshaft on a boat that was tube and it corroded til it fell apart.
mostly you find a ss shaft machined to speck for the boat and the power out
put of the engine.

but go ahead and use spring steel tube drive shafts it will give me
business.

Removing 3 bladed prop on an Alberg 35
 

On Fri, 17 Aug 2007 02:13:06 GMT, Brian Whatcott
wrote:

On Thu, 16 Aug 2007 09:59:09 -0700, Frogwatch
wrote:

I will defend my suggestion although it sounds impractical for the
Alberg. A coupler properly made...


Here's a little engineering insight. If a drive shaft is lightened
by drilling out an axial hole whose diameter is one half the outer
diameter - the shaft's strength in torque is reduced by 5% and its
weight is reduced by 25% This is important in aircraft
construction.

So as applied to cutting and shutting a propellor shaft, if its
diameter is x, and it is cut then bridged with a coupler,
the coupler's diameter ought to be just over twice the shaft's
diameter, to bridge across the gap.
....
Brian Whatcott Altus OK


I knew, sure as sure, as soon as I wrote "engineering insight" there
would be a screw-up. And there was.
If you want to maintain torque capacity though a coupling, it doesn't
need to be TWICE the shaft diameter. That's three times the cross
section area, at about twice the distance from the axis.
The coupler diameter doesn't need to be even 1.5 times the diameter
of the shaft. 1.3 times the shaft diameter would do it.
So a coupler whose diameter is about one inch bigger than the shaft
could handle up to a three inch shaft, if well connected. Yeah Baby!

Brian W

Removing 3 bladed prop on an Alberg 35
 

On Tue, 14 Aug 2007 09:14:49 -0500, "KLC Lewis"
wrote:


"Roger Long" wrote in message
...

"Frogwatch" wrote

Cut the prop shaft in the boat. Take out a 2" long section. Take off
prop. When re-installing, use a sliding coupler to join the two
pieces. This assumes you even have enough room to do this cutting.


Woah! This is up there with some of the worst advice I've encountered on
this newsgroup.

--
Roger Long


Ya, I kinda cringed when I read it. Alignment questions aside, that would
have to be one strong coupler.
Why? Isn't that just a twenty five horse motor? This is a boat, not an
electrical generating station.

Casady

Removing 3 bladed prop on an Alberg 35
 

Jonathan W wrote:
I bought an Indigo 3 bladed prop last week for my Alberg 35 with the
original Atomic 4, as the existing prop succumbed to electrolysis

I went down to the boat yesterday, worried that I might not be able to
loosen the old hub's grip on the shaft. It was also a 3 bladed prop.
That was actually easy after about 5 minutes with a map gas torch.

I seem to have only about an inch of space between the end of the prop
shaft and the rudder (post). The hub is about 2-2,5 inches thick. I've
tried swinging the rudder from stop to stop, but don't seem to be able
to find an angle that will allow the old prop to come off, or, for that
matter, a new one to go on.

Others must have encountered this problem and found a solution.....

At this juncture it seems to me that I either have to dismount the
rudder to gain an extra inch or so, or I have to unmount the engine and
pull the prop shaft forward a couple of inches (if that's even possible )

I am hoping that I missed something perfectly obvious as I was working
late and was tired.... any help appreciated.

Thanks,

Jonathan Wye



Well, the m marina figured it out. Apparently with enough patience one
could align the prop and rudder and "turn" it off. I had thought
something like this might be the case, as I was tired and it was late
when I got to the prop last weekend.

Also, some years ago I got hit by a Mack truck (literally) and sometimes
I have trouble with certain 3 dimensional space/configuration problems.
This might have been a bit of that, too.

In any event, the new prop is on, and the boat is back in the water.
Wish I could have gotten down this weekend to try it out.

thanks for all the interesting commentary :)

Jonathan

--
I am building my daughter an Argie 10 sailing dinghy, check it out:
http://home.comcast.net/~jonsailr

Removing 3 bladed prop on an Alberg 35
 

Jonathan W wrote:
Jonathan W wrote:

I bought an Indigo 3 bladed prop last week for my Alberg 35 with the
original Atomic 4, as the existing prop succumbed to electrolysis

I went down to the boat yesterday, worried that I might not be able to
loosen the old hub's grip on the shaft. It was also a 3 bladed prop.
That was actually easy after about 5 minutes with a map gas torch.

I seem to have only about an inch of space between the end of the prop
shaft and the rudder (post). The hub is about 2-2,5 inches thick.
I've tried swinging the rudder from stop to stop, but don't seem to be
able to find an angle that will allow the old prop to come off, or,
for that matter, a new one to go on.

Others must have encountered this problem and found a solution.....

At this juncture it seems to me that I either have to dismount the
rudder to gain an extra inch or so, or I have to unmount the engine
and pull the prop shaft forward a couple of inches (if that's even
possible )

I am hoping that I missed something perfectly obvious as I was working
late and was tired.... any help appreciated.

Thanks,

Jonathan Wye



Well, the m marina figured it out. Apparently with enough patience one
could align the prop and rudder and "turn" it off. I had thought
something like this might be the case, as I was tired and it was late
when I got to the prop last weekend.

Also, some years ago I got hit by a Mack truck (literally) and sometimes
I have trouble with certain 3 dimensional space/configuration problems.
This might have been a bit of that, too.

In any event, the new prop is on, and the boat is back in the water.
Wish I could have gotten down this weekend to try it out.

thanks for all the interesting commentary :)

Jonathan

I'm glad you found a solution. Having said that, what year was all of
this assembled? Maybe removing the rudder, looking for corrosion on the
pieces and giving everything as good cleaning and greasing would be a
good idea.