[Public-List] Engine Alignment

Tue Dec 29 18:48:54 PST 2009

The alignment and prop shaft in an Alberg is a wonderful thing for any 
number of experiences, mostly those that require quick thinking. I have 
had reverse back things out of the coupler even with the lock bolts in 
place, had the prop shaft let go in a big choppy swell when bolts backed 
out of the coupler and sheared,  and had the nut come off the back end 
of the transmission too. It never happens when you can get by without it 
and is always an interesting challenge. Two of the three have been in 
the Welland Canal for me,  and the other thing that can happen is that 
you wrap a line at 1:30 hours as you enter a lock. It was a 3/4" poly 
pro line and that stalled the motor as I glided to the center of the 
lock to get the lines to hold as the lock was to be evacuated. 
Fortunately, that one came free with hand turning the prop shaft in 
reverse. Otherwise I would have stopped commercial traffic and  had to 
have a diver come and free the prop. Some things do work out in the end.
     As for alignment, there is the feeler guage way to align things or 
there is the easier way if you are on a cradle. Feeler gauges are 
measuring the difference across the coupler which is about 2 1/2" and 
requires that  you to get over the engine to set the guages absolutely 
equally on both sides of the shaft and then once again for top and 
bottom. I prefer to use a bit of an extension by using the shaft and 
therefore start by  bolting  the shaft tightly onto the couplers and the 
couplers tightly together. Then I tape a sharpened wire to the rudder in 
such a way that the sharpened point aligns with the very edge of the 
shaft at the 9:00 o'clock position. The sharper the point the more 
accurate you can be. A bent coat hook wire with a sharpened end works 
well for this Then I turn the shaft. If the wire does not stay on the 
outside edge, the shaft is not aligned and the motor mounts need 
loosening and the motor needs adjusting. Two people sure help to shorten 
time for adjusting and retesting at this point. The process is repeated 
for the 12:00 position on the top of the shaft. Again the shaft is 
turned and the motor adjusted if necessary. I believe you will find it 
easier to adjust the 12:00 o'clock position first since you need to shim 
the motor mounts on this alignment. By using this method, the extra 
length of the shaft will give a more accurate measure of being out of 
alignment than gauges on the coupler because the measurement is at the 
end of a 28" shaft rather than on the outside of a 1 1/4" radius on the 
coupler.  A final test is to put the point of the wire on the dead 
center of the shaft and turn again. It should be without relative 
movement on the shaft as it turns. I then check it again with the gauges 
once in the water, but have never been more than 0.002" out. I did  have 
one owner question this method and he had a friend who had a laser and 
wanted to check the method using both the wire and laser. They said the 
wire was as accurate as the laser given the difficulty of getting the 
laser aligned with the rudder in the way. .
    One thing that you need to consider when tightening the set screws 
is to avoid breaking out the key way in the couplers. I suggest that if 
you take the coupler apart, you take a good look at the edge of the key 
way with a magnifying lens to see if there is a crack there. Most never 
look but there is very little metal left in the coupler shoulder where 
the key way is cut and if you tighten the set screw too much, you will 
break the coupler at the key way and then things loosen up on their own 
quite easily. The key can fall out under extreme conditions. And then 
there is another happy emergency. That key was originally brass so it is 
in the bilge and you cannot retrieve it with magnets even if it is still 
square. Been there,  done that too! Usually the shaft key way is not 
good either if this happens.  The best solution is to use the clamp as 
JB has suggested but try to get it balanced,  so you may use two clamps  
to offset the screw weights. If you need to get new couplers made (since 
any used ones I have looked at were also broken at the key way) then 
have the machinist offset the key ways on the coupler halves to 180 º to 
help to maintain balance. I think you will find that the current ones 
have no offset.
    Most problems begin with the transmission in reverse, and for that 
reason, I now never go into a dock under any more 'run on'  than I can 
stop with just a feather in reverse. (You get good at this if you have 
to go up a canal and have to stop in 7 locks at a pair of lines on the 
side of the wall and can't admit that reverse does not work because if 
you do, you will be refused entry!) Once the shaft exits the coupler, 
the prop will hit the rudder and that is the end of steering.  It is 
your choice on how fast you hit a wharf.
    If you have any questions e-mail me off list.
Don
#528

Amy & David Swanson wrote:
> I had a new shaft made & installed about 3 years ago.  While running 
> the engine in reverse in the slip, the prop pulled the shaft out of 
> the coupling & jammed the rudder just as you described.  I think the 
> yard left the set screws loose (they were almost completely backed 
> out), and they definitely did not put lock tite or any such thing on it.
>
> David Swanson
> Strayaway Child
> Alberg 30 #229
>
> ----- Original Message ----- From: "Thomas Moffatt" 
> <tmoffatt at xplornet.com>
> To: "Alberg 30 Public List -- open to all" 
> <public-list at lists.alberg30.org>
> Sent: Tuesday, December 29, 2009 5:36 PM
> Subject: [Public-List] Engine Alignment
>
>
>> Just thought I would throw in an educational story on engine alignment.
>>
>> I bought my Alberg 30 several decades ago, and in its previous life  
>> the engine and shaft had not been realigned, I don't believe. And  
>> every year, into the crane, out of the crane...etc.
>>
>> Took the Alberg from St. Andrews, NB down the coast of Maine to  
>> Penobscot Bay, and off North Haven was running the engine since 
>> there  was a large following swell and almost no wind. The jerking 
>> was the  final straw, I suppose...
>>
>> Suddenly the tiller would not work, and when I tried more, the boat  
>> was swirling around in circles. Put up the sails to get some control  
>> (not knowing what else to do), and of course it just made matters  
>> worse, since the Alberg was going in tight circles. Thought a 
>> lobster  pot line was grabbed, but that wasn't it.
>>
>> Finally decided to take off the steps/engine cover - and with a 
>> flashlight was horrified to see the shaft within a few inches of the 
>> thru-hull.
>>
>> Grabbed it with a wrench, and worked it forward. Then happened to  
>> have some brass "snare wire" and used it to get enough friction  
>> around the shaft, and found a way to secure the snare wire.
>>
>> Realized it was a definite blessing that the hole between hull and  
>> rudder was small enough that the propeller had fetched up against 
>> the  rudder, jamming it initially - but not allowing the shaft to leave!
>>
>> Once the shaft was secure, had my wife watch it while I used the late 
>> afternoon breezes to make it across Penobscot Bay and as the final  
>> breath of wind died, made it to one of the outer moorings in Camden  
>> harbor.
>>
>> Wayfarer Marine was happy to pull the boat the next morning, and  
>> after almost a week on the dock, I had much time to think about the  
>> matter of engine/shaft alignment. Especially as we were still living  
>> aboard, and everyone going by enjoyed the chance to ask how the  
>> cruising was up there (in the air).
>>
>> I realigned yearly from that point.
>>
>>
>> Tom Moffatt
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