[Sentoa] shaft alignment

Mike Pedersen mikeped at gmail.com
Thu Jun 21 22:06:06 EDT 2007


Jim,

No need to be upset at Bob, he's trying to help...

After spinning wrenches on ships and submarines and now while
engineering on heavy industrial equipment, I have come to understand
that most things aren't as rigid as one may initially think.  I truly
doubt that even my skookum built little Nordic Tug doesn't flex.
Heck, just last week, I measured 0.250" deflection in a 35' long 4'
diameter 2205 stainless steel core, causing fatigue cracks all over
it.  (Let's just say the repair cost would've bought a nice new 42'
NT.)

Let's face it, our boats are plastic and they sit in water, sometimes
rough water. The go through fairly drastic temperature changes.  The
engine is mounted on rubber mounts.  The cutlass bearing is rubber.
Shaft alignment will change over time as things settle and wear.  I
would also venture that the more often a boat is hauled and stored,
the more incremental the change will be.

First check your engine mounts.  Mine are soft, I need to change them.
 Watch them when you change from forward to reverse.  You can see
right away if they are too soft.  Check you cutlass bearing, as it is
rubber and can wear as well.  Not sure if 32 have a steady bearing or
not; my 26 does, it's in good shape.  I checked the straightness and
run out of the shaft through the bearing with a laser alignment tool.
You may be able to rent a laser alignment tool to do, I borrowed mine
from the mill.  I'm not quite sure how I would go about with a dial
micrometer, as there is not great reference plane.  I couldn't use the
opti-line for my alignment as it is too tight to hook up to the output
flange and spin.  So I used a feeler gage and a straight edge.  You
could use a dial indicator here to check for parallel, not sure if you
could fit face to face for angular.  Remember, you want to check for
parallel as well as angular alignment.

All this being said, I'm not a small boat mechanic.  I probably left
out some things to check while aligning.  It sounds like you have the
requisite knowledge and desire to do, so give it a try.

Regards,

Mike Pedersen
Northern Spy NT26-028
Powell River, BC

On 6/21/07, Jim Stimpson <jstimpson at torchlake.com> wrote:
> Bob,
> I was very upset when you came out with the recommendation to check the
> shaft alignment every year on boats that are taken out of the water each
> winter. I have had my boat 6 years, have logged 1600 hours and have never
> checked the alignment. I did hit a rock the second year I had the boat which
> bent the shaft. The shaft was straightened. I don't know if the yard checked
> the alignment, but I do know they did not change any adjustment on the
> mounts. Since that time I have run over 1200 hours with no vibration or
> bearing problems. I have often wondered when it would be necessary to change
> the forward cutlass bearing - what is your recommendation for that? As for
> alignment I never knew it was recommended. Your recent recommendation is the
> first time I ever heard about it. It is hard for me to understand why a
> check is necessary -once properly aligned what can cause it to change? My
> engine mount adjustment has not changed --has the boat distorted?  If this
> check is so important why was it not included in the owners manual? I
> aligned shafts over 50 years ago in a 28 ft Bay City boat I helped my dad
> build. Back then I just removed the bolts from the coupling and used a
> feeler gage to check the gap around the flange. Is this still the basic way
> to do the job?
> I think the least that Nordic Tugs can do for us owners is publish a
> recommended procedure. By the way I do not have an "A" layout and access to
> the coupling is not a problem for me.
>
> Jim Stimpson
> Tug Jimary - Duncan Bay Boat Club, Cheboygan, MI
> NTK 32-193
>
>
> ---- Original Message -----
> From: "Bob Shamek" <Bobs at nordictug.com>
> To: "South East Nordic Tugs Owners' Association (SENTOA)"
> <sentoa at lists.samurai.com>
> Sent: Thursday, June 21, 2007 5:45 PM
> Subject: Re: [Sentoa] shaft alignment
>
>
> > Carey
> > Thinking back to when I was first selling engines to Nordic the cabinets
> > over the transmission area could be removed.  I will dig through some
> > old photos and ask Jerry next week access to the coupling on A models.
> > Bob Shamek
> > Nordic Tugs
> >
> > -----Original Message-----
> > From: sentoa-bounces at lists.samurai.com
> > [mailto:sentoa-bounces at lists.samurai.com] On Behalf Of Cook, Carey
> > Sent: Thursday, June 21, 2007 2:21 PM
> > To: South East Nordic Tugs Owners' Association (SENTOA)
> > Subject: Re: [Sentoa] shaft alignment
> >
> > Bob:  Let me re-phrase the question.  I think w/ the "A" layout you need
> > to get to the shaft coupling by dismantling some of the galley cabinets
> > (e.g., the shelf under the microwave oven).  How is that done?  I can't
> > even seem to get the drawer out that is also under the microwave oven.
> > There is no way you can get to the shaft coupling from the engine
> > spaces.
> >
> >
> > Carey Cook
> > 32-138 LeeLoo
> > Racine WI (berth)
> >
> > -----Original Message-----
> > From: sentoa-bounces at lists.samurai.com
> > [mailto:sentoa-bounces at lists.samurai.com] On Behalf Of Bob Shamek
> > Sent: Thursday, June 21, 2007 3:57 PM
> > To: South East Nordic Tugs Owners' Association (SENTOA)
> > Subject: Re: [Sentoa] shaft alignment
> >
> > I have never checked the alignment on a 'A' layout 32 so its had for me
> > to comment on optional long feeler gauge maybe it the way to go.  Or
> > tall skinny guy at the boat yard!
> > Bob Shamek
> >
> >
> > -----Original Message-----
> >>> Question directed to Bob Shamek...
> >>
> >> Bob,
> >>
> >> Do you have a method or description of aligning the shaft in an NT32.
> >> With my sailboats,
> >> shaft alignment was simple.  Once back in the water, loosen the bolts
> >> at the shaft/transmission coupling, then re-tighten.  Same way ?
> >>
> >> John Baczek
> >> Puffin, NT32-266
> >>
> >> !DSPAM:448,467a7254318239538111582!
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> >>
> >
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