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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 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 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)