"Evan Gatehouse" wrote

I'm sort of disagreeing with Roger here with his suggestion (I
think) of flexibly mounted engines but a rigid shaft coupling.

It's probably not a disagreement but having lost track here of a point
in the thread. I'm talking about a specific drive train configuration
which is common on sailboats.

There must be a flexible stuffing box or shaft seal and there must be
no other bearings other than the stern strut. The engine can be on
very soft mounts. There is then nothing except the cutlass to pick up
any shaft vibration. The shaft is long enough to flex and accommodate
the engine motion. The full length version of this video

http://marine.unh.edu/Images/Gulf%20Challenger.wmv

shows a cup of coffee sitting on the quarter bit while the boat is
going 20 knots and there isn't a ripple on the surface. The struts
pick up very little vibration.

As soon as you introduce a second bearing into a the shaft system with
soft engine mounts, you have to have something flexible between the
gear and the shaft. I've made the shafts slightly oversize on my fast
research vessels to eliminate the need for a second bearing, way, way,
cheaper than installing and lining up that second bearing.

BTW there is a direct relationship between how much the engine can
move and the frequency of vibration isolated. Thin rubber pads take
out the high whine but getting the low throb and rumble out requires
letting the engine move 3/8" to 1/2" as you say you are doing.

--

Roger Long

Evan,

I'm curious. What kind of boats does a phone company design or is
your header showing something odd for an organization?

--

Roger Long



"Evan Gatehouse" wrote in message
...
I'm sort of disagreeing with Roger here with his suggestion (I
think) of flexibly mounted engines but a rigid shaft coupling. On
all the vessels that we design, 95% use flexible mounts. We like
Lo-Rez because they are very soft (~0.5" static deflection). But to
use them you HAVE to have a flexible coupling because otherwise all
that vibration will get into the structure via the shaft and
stuffing box.

Evan Gatehouse

"Roger Long" wrote in message
...

Skip the drive saver. Line up your shaft carefully calculating the
overhanging weight of the shaft and using a scale to hold the end up. Make
sure the flanges are true and the pilot concentric. Then hard mount it.
The metal parts will then be more precision than a plastic disk can ever
be and will stay that way. It will run fine.

If you see my pix of the installation to come, at
http://justpickone.org/skip/gallery/...06&sta rt=297, I
believe I qualify on the pilot/hard mount bit.

However, my question has to do with weighing the shaft. Currently the
packing's out of the gland, awaiting mount/alignment before repacking, so
it's floppy on its hose, so far as it can move.

Reading Calder on the subject, I'm not clear on how I measure the weight and
position the flange for alignment with the transmission. Of course, there's
some possibility it was done properly the first time, when they changed out
the engine, rebuilt the tranny and changed to SS shaft, but given what I've
seen in our refit, and the simple fact of the current, were it bolted back
up, misalignment, I doubt it.

So, could you elaborate on that (weighing and positioning)?

Thanks.

L8R

Skip, sore from PT today, not lifting 125# batteries, but wishing it were...


--
L8R

Skip

Morgan 461 #2
SV Flying Pig KI4MPC
http://tinyurl.com/384p2 The vessel as Tehamana, as we bought her

"Believe me, my young friend, there is *nothing*-absolutely nothing-half so
much worth doing as simply messing, messing-about-in-boats; messing about in
boats-or *with* boats.
In or out of 'em, it doesn't matter. Nothing seems really to matter, that's
the charm of it.
Whether you get away, or whether you don't; whether you arrive at your
destination or whether you reach somewhere else, or whether you never get
anywhere at all, you're always busy, and you never do anything in
particular; and when you've done it there's always something else to do, and
you can do it if you like, but you'd much better not."

If you just have a single shaft bearing, just ahead of the prop, you
don't need to weigh the shaft. Just suspend it so it is centered as
closely as possible in the stern tube. Be sure to hang and fix it by
the coupling or close to it. Some stuffing boxes also incorporate a
bearing so check carefully. If there is a bearing in the stuffing
box, it's a bearing. If your stuffing box isn't flexible, there
probably is a bearing in there somewhere.

If you have two bearings, measure the length and diameter from the
forward shaft end to the bearing and calculate the volume and weight
(.28 lbs / cubic inch is close enough). Divide by 2. Then calculate
the volume and weight of the coupling. Add the two weights. Hang the
coupling so a pull scale inserted in the wire reads this amount. You
will then not be lining up to a shaft that is drooping under it's own
weight.

On further reflection: shafts in most sailboats are probably so short
that this isn't a big issue. On power boats, there will often be
several feet of shaft between the bearing and the gear. Still, it
wouldn't hurt to hang and weight it. We're talking about very small
tolerances here.

--

Roger Long



"Skip Gundlach" skipgundlach at gmail dotcom wrote in message
...
"Roger Long" wrote in message
...

Skip the drive saver. Line up your shaft carefully calculating the
overhanging weight of the shaft and using a scale to hold the end
up. Make sure the flanges are true and the pilot concentric. Then
hard mount it. The metal parts will then be more precision than a
plastic disk can ever be and will stay that way. It will run fine.

If you see my pix of the installation to come, at
http://justpickone.org/skip/gallery/...06&sta rt=297, I
believe I qualify on the pilot/hard mount bit.

However, my question has to do with weighing the shaft. Currently
the packing's out of the gland, awaiting mount/alignment before
repacking, so it's floppy on its hose, so far as it can move.

Reading Calder on the subject, I'm not clear on how I measure the
weight and position the flange for alignment with the transmission.
Of course, there's some possibility it was done properly the first
time, when they changed out the engine, rebuilt the tranny and
changed to SS shaft, but given what I've seen in our refit, and the
simple fact of the current, were it bolted back up, misalignment, I
doubt it.

So, could you elaborate on that (weighing and positioning)?

Thanks.

L8R

Skip, sore from PT today, not lifting 125# batteries, but wishing it
were...


--
L8R

Skip

Morgan 461 #2
SV Flying Pig KI4MPC
http://tinyurl.com/384p2 The vessel as Tehamana, as we bought her

"Believe me, my young friend, there is *nothing*-absolutely
nothing-half so much worth doing as simply messing,
messing-about-in-boats; messing about in boats-or *with* boats.
In or out of 'em, it doesn't matter. Nothing seems really to
matter, that's the charm of it.
Whether you get away, or whether you don't; whether you arrive at
your destination or whether you reach somewhere else, or whether you
never get anywhere at all, you're always busy, and you never do
anything in particular; and when you've done it there's always
something else to do, and you can do it if you like, but you'd much
better not."

The key thing is where and how you support the shaft. If it is a
single strut bearing system, you would like to have it end up centered
in the tube the flexible box hose attaches to in order not to have any
preset on the hose and maximize the possible movement in all
directions. One way to do that would be put wedges or a bushing in
the stern tube. You would then have three feet of shaft sticking out
with a coupling on the end and I would say, yes, you should weight it.

Simpler would just be to support it at the coupling and adjust for
equal spacing in the stern tube. The shaft will sag some small amount
but this will not be significant to the flexible stuffing box in the
way that the coupling face angle error would be with the overhanging
shaft bending down.

Speaking of the angles, do you have a dial gauge? It looks from the
pictures like the faces were cleaned up a lot. Unless the
transmission coupling was checked in the shop, you should set up a
dial gauge and turn it by hand to be sure it is truly square. The
coupling style you have makes this a pain to do as you have to be
careful not to knock the whole thing out of its base setting as it
skips over the cut outs. You want to also check the shaft the same
way. This is hard in the boat because the bearings make it want to
"screw" for and aft as you turn it, even if the helper manages not to
push for and aft on the prop.

The whole idea is to get the geometry such that, if the shaft was
weightless and just sticking off the end of the engine, the center at
the prop nut end would not be going around in a little circle as the
shaft turned. As the engine moves around on its mounts there will be
larger misalignments and flexing in the whole system. However, if the
shaft is attached at even a slight angle, the engine will be trying to
wave the whole thing around in that circle. Since this happens on
every revolution it is rhythmic and sets up impulses that something
will resonate to and you have vibration.

How many shaft diameters do you have between the coupling and the
shaft bearing? Might be better to look for any red flags now than
after it is all together.

--

Roger Long



"Skip Gundlach" skipgundlach at gmail dotcom wrote in message
...
Hi, Roger, and thanks for the response, left below.

The shaft in the M46 is pretty long. I've not measured it, but I'm
guessing 7-8 feet minimum.

The stuffing box is on a hose, which is flexible; there's a tube
from the stuffing box, through the hull, and out to the cutlass.
The last few inches of the cutlass are cut away ~45* to half
coverage, making a water vent, and the tube is kerf-width slit in a
couple of places on the bottom, between the keel and the Pstrut for
about 20* or so for more water lubrication.

So, I'm reasonably sure there's not an intermediate bearing; there
had been one, not far before the stuffing box, but it was removed,
presumably when the SS shaft (stiffer, I'd assume) replaced the
Bronze original.

However, there's lots of length between the stuffing box and the
tranny - 3' or more, I'd say. Does that impact your advice (for
which I'm grateful)?

Thanks.

--
L8R

Skip

Morgan 461 #2
SV Flying Pig KI4MPC
http://tinyurl.com/384p2 The vessel as Tehamana, as we bought her

"Believe me, my young friend, there is *nothing*-absolutely
nothing-half so much worth doing as simply messing,
messing-about-in-boats; messing about in boats-or *with* boats.
In or out of 'em, it doesn't matter. Nothing seems really to
matter, that's the charm of it.
Whether you get away, or whether you don't; whether you arrive at
your destination or whether you reach somewhere else, or whether you
never get anywhere at all, you're always busy, and you never do
anything in particular; and when you've done it there's always
something else to do, and you can do it if you like, but you'd much
better not."

"Roger Long" wrote in message
...
If you just have a single shaft bearing, just ahead of the prop,
you don't need to weigh the shaft. Just suspend it so it is
centered as closely as possible in the stern tube. Be sure to hang
and fix it by the coupling or close to it. Some stuffing boxes
also incorporate a bearing so check carefully. If there is a
bearing in the stuffing box, it's a bearing. If your stuffing box
isn't flexible, there probably is a bearing in there somewhere.

If you have two bearings, measure the length and diameter from the
forward shaft end to the bearing and calculate the volume and
weight (.28 lbs / cubic inch is close enough). Divide by 2. Then
calculate the volume and weight of the coupling. Add the two
weights. Hang the coupling so a pull scale inserted in the wire
reads this amount. You will then not be lining up to a shaft that
is drooping under it's own weight.

On further reflection: shafts in most sailboats are probably so
short that this isn't a big issue. On power boats, there will
often be several feet of shaft between the bearing and the gear.
Still, it wouldn't hurt to hang and weight it. We're talking about
very small tolerances here.

--

Roger Long

In the commercial world, the flange on the gear is trued up so that
the outside edge is exactly concentric and the face exactly
perpendicular to the shaft. That flange is then mated to the
propeller shaft flange which is trued up after being installed on the
shaft with the whole thing being turned in a lathe or other fixture.

Amen. For years I had an minor vibration in the auxiliary on my 36'
sailboat, which engine realignment, new cutlass bearing, and new engine
mounts didn't change. On last haulout, after a transmission swap (with
a trued output flange), the yard recommended the above procedure and
voila', vibration gone.

Skip,

Thinking about it some more, there is a lot to be said from the
practical side from fixing it solidly in the stern tube. With all the
squirming around in tight space, you're less likely to bump it out of
the desired line. Weighing the shaft also would then align it with
minimal sag. (Use the length from the wedges or split bushing in the
stern tube for the calculation.) If you are up around or over 40
shaft diameters of unsupported length, this could make a detectable
difference, but only if you had two absolutely identical boats and
listened carefully. Since you'll never know, may as well cover the
bases.

--

Roger Long



"Roger Long" wrote in message
...
The key thing is where and how you support the shaft. If it is a
single strut bearing system, you would like to have it end up
centered in the tube the flexible box hose attaches to in order not
to have any preset on the hose and maximize the possible movement in
all directions. One way to do that would be put wedges or a bushing
in the stern tube. You would then have three feet of shaft sticking
out with a coupling on the end and I would say, yes, you should
weight it.

Simpler would just be to support it at the coupling and adjust for
equal spacing in the stern tube. The shaft will sag some small
amount but this will not be significant to the flexible stuffing box
in the way that the coupling face angle error would be with the
overhanging shaft bending down.

Speaking of the angles, do you have a dial gauge? It looks from the
pictures like the faces were cleaned up a lot. Unless the
transmission coupling was checked in the shop, you should set up a
dial gauge and turn it by hand to be sure it is truly square. The
coupling style you have makes this a pain to do as you have to be
careful not to knock the whole thing out of its base setting as it
skips over the cut outs. You want to also check the shaft the same
way. This is hard in the boat because the bearings make it want to
"screw" for and aft as you turn it, even if the helper manages not
to push for and aft on the prop.

The whole idea is to get the geometry such that, if the shaft was
weightless and just sticking off the end of the engine, the center
at the prop nut end would not be going around in a little circle as
the shaft turned. As the engine moves around on its mounts there
will be larger misalignments and flexing in the whole system.
However, if the shaft is attached at even a slight angle, the engine
will be trying to wave the whole thing around in that circle. Since
this happens on every revolution it is rhythmic and sets up impulses
that something will resonate to and you have vibration.

How many shaft diameters do you have between the coupling and the
shaft bearing? Might be better to look for any red flags now than
after it is all together.

--

Roger Long



"Skip Gundlach" skipgundlach at gmail dotcom wrote in message
...
Hi, Roger, and thanks for the response, left below.

The shaft in the M46 is pretty long. I've not measured it, but I'm
guessing 7-8 feet minimum.

The stuffing box is on a hose, which is flexible; there's a tube
from the stuffing box, through the hull, and out to the cutlass.
The last few inches of the cutlass are cut away ~45* to half
coverage, making a water vent, and the tube is kerf-width slit in a
couple of places on the bottom, between the keel and the Pstrut for
about 20* or so for more water lubrication.

So, I'm reasonably sure there's not an intermediate bearing; there
had been one, not far before the stuffing box, but it was removed,
presumably when the SS shaft (stiffer, I'd assume) replaced the
Bronze original.

However, there's lots of length between the stuffing box and the
tranny - 3' or more, I'd say. Does that impact your advice (for
which I'm grateful)?

Thanks.

--
L8R

Skip

Morgan 461 #2
SV Flying Pig KI4MPC
http://tinyurl.com/384p2 The vessel as Tehamana, as we bought her

"Believe me, my young friend, there is *nothing*-absolutely
nothing-half so much worth doing as simply messing,
messing-about-in-boats; messing about in boats-or *with* boats.
In or out of 'em, it doesn't matter. Nothing seems really to
matter, that's the charm of it.
Whether you get away, or whether you don't; whether you arrive at
your destination or whether you reach somewhere else, or whether
you never get anywhere at all, you're always busy, and you never do
anything in particular; and when you've done it there's always
something else to do, and you can do it if you like, but you'd much
better not."

"Roger Long" wrote in message
...
If you just have a single shaft bearing, just ahead of the prop,
you don't need to weigh the shaft. Just suspend it so it is
centered as closely as possible in the stern tube. Be sure to
hang and fix it by the coupling or close to it. Some stuffing
boxes also incorporate a bearing so check carefully. If there is
a bearing in the stuffing box, it's a bearing. If your stuffing
box isn't flexible, there probably is a bearing in there
somewhere.

If you have two bearings, measure the length and diameter from the
forward shaft end to the bearing and calculate the volume and
weight (.28 lbs / cubic inch is close enough). Divide by 2. Then
calculate the volume and weight of the coupling. Add the two
weights. Hang the coupling so a pull scale inserted in the wire
reads this amount. You will then not be lining up to a shaft that
is drooping under it's own weight.

On further reflection: shafts in most sailboats are probably so
short that this isn't a big issue. On power boats, there will
often be several feet of shaft between the bearing and the gear.
Still, it wouldn't hurt to hang and weight it. We're talking
about very small tolerances here.

--

Roger Long

Hi, Roger, and group,

Thanks again for knowledgeable insight, left below and in the prior post.

Fortunately, in our boat, access is very open, so squirming around isn't an
issue - but it's what drives the suspended length.

I'm not going to be back on the boat for a couple of weeks, but when I am,
I'll pull the hose from the tube and do as you suggest about shimming and
see what the result is for the flange end.

I'll also check the length. I don't think it's 50 inches, but I'd be
surprised if it weren't more than 36.

And, you're correct. I cleaned up the faces with the rotary cup brush on a
grinder as shown in one of the pix. Not a milled surface, but pretty well
cleaned of rust lumps. Unfortunately, I don't have a dial gauge - though I
suppose I could find one to borrow. I painfully see your point about the
faces of the flanges - but don't know whether I feel it worth pulling both
of them out (the end of the shaft would be challenging, as I'm pretty sure
it's seized; the tranny would just be a nuisance, as I'd take the plate with
it off to some machine shop).

Hm. Without the shaft being in it, the shaft plate suffers the potential to
move from dead flush by virtue of the split end clamping. That gets into
some major work to attempt to ascertain (which would allow correction, of
course, but then would have to be disassembled again to reinstall - I guess
the trick would be multiple mount/dismounts at the shop to be sure it stayed
that way when reattached?) what flush is on that assembly.

Heh. The drive saver is looking more attractive just from a slop
perspective, though I'm still going to use the solid biscuit...

Thanks again.

L8R

Skip

Morgan 461 #2
SV Flying Pig KI4MPC
http://tinyurl.com/384p2 The vessel as Tehamana, as we bought her

"Believe me, my young friend, there is *nothing*-absolutely nothing-half so
much worth doing as simply messing, messing-about-in-boats; messing about in
boats-or *with* boats.
In or out of 'em, it doesn't matter. Nothing seems really to matter, that's
the charm of it.
Whether you get away, or whether you don't; whether you arrive at your
destination or whether you reach somewhere else, or whether you never get
anywhere at all, you're always busy, and you never do anything in
particular; and when you've done it there's always something else to do, and
you can do it if you like, but you'd much better not."

----- Original Message -----
From: "Roger Long"
Newsgroups: rec.boats.cruising,rec.boats.building
Sent: Sunday, April 02, 2006 4:21 PM
Subject: Drive alignment (was) Drive Saver/Spacer users sought


Skip,

Thinking about it some more, there is a lot to be said from the practical
side from fixing it solidly in the stern tube. With all the squirming
around in tight space, you're less likely to bump it out of the desired
line. Weighing the shaft also would then align it with minimal sag. (Use
the length from the wedges or split bushing in the stern tube for the
calculation.) If you are up around or over 40 shaft diameters of
unsupported length, this could make a detectable difference, but only if
you had two absolutely identical boats and listened carefully. Since
you'll never know, may as well cover the bases.

--

Roger Long



"Roger Long" wrote in message
...
The key thing is where and how you support the shaft. If it is a single
strut bearing system, you would like to have it end up centered in the
tube the flexible box hose attaches to in order not to have any preset on
the hose and maximize the possible movement in all directions. One way
to do that would be put wedges or a bushing in the stern tube. You would
then have three feet of shaft sticking out with a coupling on the end and
I would say, yes, you should weight it.

Simpler would just be to support it at the coupling and adjust for equal
spacing in the stern tube. The shaft will sag some small amount but this
will not be significant to the flexible stuffing box in the way that the
coupling face angle error would be with the overhanging shaft bending
down.

Speaking of the angles, do you have a dial gauge? It looks from the
pictures like the faces were cleaned up a lot. Unless the transmission
coupling was checked in the shop, you should set up a dial gauge and turn
it by hand to be sure it is truly square. The coupling style you have
makes this a pain to do as you have to be careful not to knock the whole
thing out of its base setting as it skips over the cut outs. You want to
also check the shaft the same way. This is hard in the boat because the
bearings make it want to "screw" for and aft as you turn it, even if the
helper manages not to push for and aft on the prop.

The whole idea is to get the geometry such that, if the shaft was
weightless and just sticking off the end of the engine, the center at the
prop nut end would not be going around in a little circle as the shaft
turned. As the engine moves around on its mounts there will be larger
misalignments and flexing in the whole system. However, if the shaft is
attached at even a slight angle, the engine will be trying to wave the
whole thing around in that circle. Since this happens on every
revolution it is rhythmic and sets up impulses that something will
resonate to and you have vibration.

How many shaft diameters do you have between the coupling and the shaft
bearing? Might be better to look for any red flags now than after it is
all together.

--

Roger Long



"Skip Gundlach" skipgundlach at gmail dotcom wrote in message
...
Hi, Roger, and thanks for the response, left below.

The shaft in the M46 is pretty long. I've not measured it, but I'm
guessing 7-8 feet minimum.

The stuffing box is on a hose, which is flexible; there's a tube from
the stuffing box, through the hull, and out to the cutlass. The last few
inches of the cutlass are cut away ~45* to half coverage, making a water
vent, and the tube is kerf-width slit in a couple of places on the
bottom, between the keel and the Pstrut for about 20* or so for more
water lubrication.

So, I'm reasonably sure there's not an intermediate bearing; there had
been one, not far before the stuffing box, but it was removed,
presumably when the SS shaft (stiffer, I'd assume) replaced the Bronze
original.

However, there's lots of length between the stuffing box and the
tranny - 3' or more, I'd say. Does that impact your advice (for which
I'm grateful)?

Thanks.

--
L8R

Skip

Morgan 461 #2
SV Flying Pig KI4MPC
http://tinyurl.com/384p2 The vessel as Tehamana, as we bought her

"Believe me, my young friend, there is *nothing*-absolutely nothing-half
so much worth doing as simply messing, messing-about-in-boats; messing
about in boats-or *with* boats.
In or out of 'em, it doesn't matter. Nothing seems really to matter,
that's the charm of it.
Whether you get away, or whether you don't; whether you arrive at your
destination or whether you reach somewhere else, or whether you never
get anywhere at all, you're always busy, and you never do anything in
particular; and when you've done it there's always something else to do,
and you can do it if you like, but you'd much better not."

"Roger Long" wrote in message
...
If you just have a single shaft bearing, just ahead of the prop, you
don't need to weigh the shaft. Just suspend it so it is centered as
closely as possible in the stern tube. Be sure to hang and fix it by
the coupling or close to it. Some stuffing boxes also incorporate a
bearing so check carefully. If there is a bearing in the stuffing box,
it's a bearing. If your stuffing box isn't flexible, there probably is
a bearing in there somewhere.

If you have two bearings, measure the length and diameter from the
forward shaft end to the bearing and calculate the volume and weight
(.28 lbs / cubic inch is close enough). Divide by 2. Then calculate
the volume and weight of the coupling. Add the two weights. Hang the
coupling so a pull scale inserted in the wire reads this amount. You
will then not be lining up to a shaft that is drooping under it's own
weight.

On further reflection: shafts in most sailboats are probably so short
that this isn't a big issue. On power boats, there will often be
several feet of shaft between the bearing and the gear. Still, it
wouldn't hurt to hang and weight it. We're talking about very small
tolerances here.

--

Roger Long

If you used a grinder on those coupling faces, I would strongly advise
pulling the shaft and having at least that coupling trued up. At the
same
time, they can check for straightness, wear that will shorten bearing
life,
prop taper fit, etc. Straightness is a greatly overlooked issue,
especially
in the long shafts that many pleasure boats have. The offcenter mass
in the
middle pulls the shaft out of line which puts the mass farther from
the axis
of rotation. The result is many pounds of steel spinning off center.
It's
tough on your rear end, your ears, and all the bearings in the system.
It
can also work your flexible stuffing box overtime.

The transmission is a tougher matter but the fit on the shaft is apt
to be
better than the prop shaft since it was presumably done at the
factory. I
would pull that coupling and have them do what they can with it. You
might
also look into buying one that fits and is full round so you can align
and
check it more easily. Buy or rent a dial gauge and check it in the
boat
after reassembly.

It's always painful to insert a major project like this into the
schedule at
this stage but you are going to spend many hours listening to that
engine.
Vibration increases fatigue and weakens components in other systems.
If it
isn't smooth, it's going to cost much more time and money to fix it
later.

You don't have a thrust bearing so you can't put in anything soft
enough to
accommodate any real misalignment. A Drivesaver will mitigate but
it's only
going to take the edge off the kind of problems you could have in that
coupling.

Friend of mine has the identical boat. With the same kind of prop,
his
vibrates like crazy while mine is smooth. I haven't touched my
shaftline
yet so it's just luck but it does show that subtle things can have
large
effects. He has a Drivesafer too.

Sound like you are going to be sailing off over the horizon. You are
really
going to be depending on that engine. This is the time to be sure the
shaftline is right.

--

Roger Long

"Skip Gundlach" skipgundlach at gmail dotcom wrote

It was just a cup wire wheel. Does that change your thinking?

I was assuming that this is a boat you haven't run before but that's a
point worth checking on my part. If it was smooth before, than the
risk is less of leaving it as it is. If you don't have any operation
history, I would sure want to pull it myself. Wire wheeling shouldn't
have taken that much off.

Just remember that the tiny angular misalignment at the shaft is
magnified at the shaft end by the ratio of the coupling diameter to
the shaft length. Even though a Drivesaver will pick up some of that,
it's hard enough to transmit the remaining impulses through to the
transmission and stern bearing. Pick up the disk in your hand, think
of the force to push one edge down even a few thousandths of an inch
and then imagine that being exerted on your engine and shaft
00 -1000 times per minute.

You said you got the point but I can't resist saying: Smooth is good.
Imagine motoring 12 -18 hours to beat the weather and having to run a
very challenging and complex inlet. Vibration and noise fatigue can
be more than just a comfort issue.

--

Roger Long