boat pulling to port when using motor!! Distress!

[Indian Falls]

Are you sure they put "your" prop back on?

[Ken Juul]

The first season after I did the Ron Hill make your rudder eliptical mod I didn't get it quite right.  Had a similar pull to port.  The following spring I re-faired the rudder and the pull went away.  It really sounds like somehow the trailing edge of the rudder has been bent.  Goes along with what prh77 mentioned.

[Clay Greene]

I had the same thoughts as to both the rudder and the steering system but neither makes sense if the pull is occurring only under power and not under sail as well.  That's why I think it has to be something in the shaft-strut-propeller system that is causing the force applied under power to be significantly off-center. 

[prh77]

I think the difference under power versus sail has to do with water flow over the rudder ie under power more flow. I also agree that a strut/shaft misalignment that would generate that kind of pull would also vibrate like hell. So I am still leaning twords a rudder issue.

[Clay Greene]

I would agree with you if you are comparing sailing at three knots to motoring at six knots.  But if the boat is sailing at six knots and not pulling to port but is doing so motoring at six knots, I think you have to look at the shaft and prop as the most likely causes. 

If the boat was pulling to port under sail, my first guess would be the steering system as that is more likely to be out of adjustment than major damage to the rudder or the rudder post. 

[kerk fisher]

Hi all.  I just got back from the boat which is 600 miles away.  Found something interesting.  The main tech person at the yard noticed that the shaft is coming through the shaft log very close to the starboard side, almost touching, way off center. Could this be the problem??? The strut is straight.  (All else looked good, prop is ours, rudder was new elliptical a few years ago) I looked at the cutlass bearing briefly and it looked good although it was only on the journey home that I wish I had looked more carefully to see if I could notice slight uneven wear. Would this shaft position provide enough of an angle so that the prop pushes the stern to starboard and the bow to port? I"m not sure why this would be so out of alignment.....  We didn't notice much vibration at all. Nothing out of the ordinary.  I've never done the alignment although it was done by another yard when the new shaft was put in. Will these techs be able to determine in the alignment process that the shaft is centered in the log even when the boat's in the water and cover by ( in the interior) by a PSS Packless sealing system.  I wanted to send a photo but nothing worked.(any hints on this process?)  Thanks, Kerk

[Ken Juul]

Possibly.  But you really need to check the shaft alignment with the boat in the water.  The apparent misalignment may just be the way they have the boat supported by the jack stands.

[Stu Jackson]

I wanted to send a photo but nothing worked.(any hints on this process?)

Kerk,

Posting Photos 101  http://c34.org/bbs/index.php/topic,3701.0.html

[scotty]

I re-read your post.  The problem is more than just a prop walk issue.  It showed up after you had a new shaft put in, so I would start there.  You should be able to fix this!!

[Ron Hill]

Kirk : I've reread all of your posts and it sounds as though your problem has just started after the new stainless shaft was installed - is that correct??

If that is correct, it also sounds as though the yard must have changed the position of the shaft so it is now NOT centered in the middle of the molded tube that passes thru the hull which the PSS is attached to. 
I'll guess that the yard messed up that alignment installing the new stainless shaft thru the PSS dripless gland.  They did the work on land and never rechecked that alignment when the boat was back in the water. 
It is imperative to check final shaft alignment when the boat is back in the water for at least 24 hours with the rigging tuned.

A few thoughts

[Indian Falls]

What RPM are you at when this happens?  Are you sure the tachometer is accurate?
Did they put the same prop back on that they took off?  Did they ruin your prop and then put one on that was laying around?  Your shaft misalignment will not pull your boat port or starboard, an 1/8'' of an inch over 5 feet means nothing to your problem with steerage.
Do you have the same prop walk to port when in reverse that you had all along before the shaft change?  I feel a lot of prop wash on my rudder through the wheel when I change direction and put the throttle up to 2000 rpm, but as soon as I get a few knots on the knot log that sensation goes away.  If I let go of the wheel and it's not locked the boat will careen right or left, but this is not a struggle if holding the wheel, nor is it a struggle to hold a straight course underway.  Hopefully all the experience available here will help you get to the bottom of this.   Good one...

[kerk fisher]

Again, thanks all for your continued interest in this mystery.  To clarify.  The problem began the second season after the new shaft and the pss was put in.  Maybe the alignment took a season to get out of wack?  Indian Falls thinks the alignment would not create the problem but maybe you, Ron, think it might.  Believe it or not we only backed one time this season because we only sailed for one week of anchoring due to an emergency abort mission to return home to an ailing mother-in-law so can't speak to the issue of prop wash while in reverse.

Three pix are included: 1. showing the shaft through the log.  2. The strut (what is the water stain?) 3.  The rudder. Clearance seems rather close at the top aft section of the rudder.  Note: bottom paint will be applied in the spring!

[Jeff Tancock]

That strut is looking very suspicious......
Grab it and give it a good push/pull from each side. It could be mush.
I discovered mine was shot when I was having some other work done last year. Electrolysis had destroyed it gradually over time.

[Roc]

The shaft coming out of the hull off center can be due to the fact that the boat is on stands.  The hull could be distorted.  On my boat, when on stands, some interior cabinet doors don't align as well as when the boat's in the water.

[Ron Hill]

Kirk : Eyeballwise, The shaft should be coming out of the middle of the "hole in the hull".  Even on jack stands the bottom of the hull should not be warped that much.  If the yard knows what they are doing the jack-stands should be where there is a bulkhead and you should only experience side hull warp (the doors won't close right)!!

With the boat out of the water try this.  Remove the 4 bolts that couple the shaft to the transmission and then see how the shaft is - in or out of center.  Also shove the shaft (with prop attached) aft 5 or 6 inches and look at the wear pattern on the shaft from the cutless bearing (I assume that the strut is solidly secure?). 
Also move the shaft back in to place and it should easily mate back up at the transmission attaching points.

I still believe that your problem started and is caused by an improper installation of your stainless shaft.

A few thoughts