Drive Saver/Spacer users sought
 

Hi, Lists,

Thanks for all the responses to my line cutter question. To put one on will
require some more space, and, in general, I've come to think that a
break-away (with built-in safeguards to allow continued use until
replacement) spacer is also a good move.

Who here has had one, and, best, has had to use it to save their gear?

Thanks again.

L8R

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

"Twenty years from now you will be more disappointed by the things you
didn't do than by the ones you did do. So throw off the bowlines. Sail
away from the safe harbor. Catch the trade winds in your sails. Explore.
Dream. Discover." - Mark Twain

Drive Saver/Spacer users sought
 

In article ,
"Skip Gundlach" skipgundlach at gmail dotcom wrote:

Thanks for all the responses to my line cutter question. To put one on will
require some more space, and, in general, I've come to think that a
break-away (with built-in safeguards to allow continued use until
replacement) spacer is also a good move.

Who here has had one, and, best, has had to use it to save their gear?

We've had one for about a decade. Hasn't broken from normal use.

So far, we have avoided wrapping a line while the engine was running, so
I don't know if it'll work when the time comes, but I worry less.

Nice side-effect was that it takes up slight misalignments, smoothing
the slight vibrations out.

Note: Ours is solid "rubber". The pics of the more recent ones make them
look more engineered.

--
Jere Lull
Xan-a-Deux ('73 Tanzer 28 #4 out of Tolchester, MD)
Xan's Pages: http://members.dca.net/jerelull/X-Main.html
Our BVI FAQs (290+ pics) http://homepage.mac.com/jerelull/BVI/

Drive Saver/Spacer users sought
 

For what it's worth, I deal often with one of the foremost drivetrain
and propulsion specialists in the country in connection with designing
boats like this:

http://home.maine.rr.com/rlma/WHOIrv.htm

The shipyard that builds these boat specializes in fast,
sophisticated, high powered craft. Both told me that they hate
"Drivesavers". The boat in the picture has two 710 horsepower engines
with the engines flex mounted and the shafts connected with solid
couplings. There is just one bearing, in the shaft strut. They run
smooth as silk.

I do have a drivesaver disk in my boat but they cut the shaft short
when they installed it so I have to buy a whole new shaft to take it
out. It's not causing any problems that I can see though other than
making it a pain to repack the stuffing box.

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.

There's a whole range of prop strike forces where the drive saver
could break but the solid coupling would still leave you able to limp
off a lee shore with the engine vibrating and shaking. I like that
scenario better. I've heard of a lot more broken shafts and totally
trashed props than gear boxes that failed due to prop strike. The
gears are a lot more rugged than you would think. Remember that there
is a friction clutch in the system that will give some under an
extreme shock load.

--

Roger Long



"Skip Gundlach" skipgundlach at gmail dotcom wrote in message
...
Hi, Lists,

Thanks for all the responses to my line cutter question. To put one
on will require some more space, and, in general, I've come to think
that a break-away (with built-in safeguards to allow continued use
until replacement) spacer is also a good move.

Who here has had one, and, best, has had to use it to save their
gear?

Thanks again.

L8R

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

"Twenty years from now you will be more disappointed by the things
you
didn't do than by the ones you did do. So throw off the bowlines.
Sail
away from the safe harbor. Catch the trade winds in your sails.
Explore.
Dream. Discover." - Mark Twain

Drive Saver/Spacer users sought
 

Hi, Roger, and List/Group,

This really has more to do with a spacer than drive saver, though I like the
flexibility of it in case the alignment isn't perfect.

Those of you who have been around a couple of years know how we jacked the
tranny out of the mounting plate (now replaced, no harm done other than
inconvenience in making up a keeper to stay moving with the engine, and the
packing gland needing redoing cuz of the weight of the tranny on the shaft
when it came out, also redone). Recent readers also know of my search for
line cutters, which would have prevented that (which shouldn't have
happened, but stupid sailor tricks happen all the time, anyway, so a mooring
line overboard isn't guaranteed against for all time on our boat, as much as
we'd like to think so, and, of course the occasional lobster/crab pot warp I
don't see in the middle of the night) - which will require a longer shaft,
or...

.... a spacer - so why not a flexible one?

And, I was looking for input from those who'd had a use for one preferably
where the thing sheared and left the 'limp home' mode in place.

I agree about proper alignment - and that will happen before we insert a
spacer or drive saver...

L8R

Skip, back to the boat for two weeks in a few days


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

"Twenty years from now you will be more disappointed by the things you
didn't do than by the ones you did do. So throw off the bowlines. Sail
away from the safe harbor. Catch the trade winds in your sails. Explore.
Dream. Discover." - Mark Twain
"Roger Long" wrote in message
...
For what it's worth, I deal often with one of the foremost drivetrain and
propulsion specialists in the country in connection with designing boats
like this:

http://home.maine.rr.com/rlma/WHOIrv.htm

The shipyard that builds these boat specializes in fast, sophisticated,
high powered craft. Both told me that they hate "Drivesavers". The boat
in the picture has two 710 horsepower engines with the engines flex
mounted and the shafts connected with solid couplings. There is just one
bearing, in the shaft strut. They run smooth as silk.

I do have a drivesaver disk in my boat but they cut the shaft short when
they installed it so I have to buy a whole new shaft to take it out. It's
not causing any problems that I can see though other than making it a pain
to repack the stuffing box.

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.

There's a whole range of prop strike forces where the drive saver could
break but the solid coupling would still leave you able to limp off a lee
shore with the engine vibrating and shaking. I like that scenario better.
I've heard of a lot more broken shafts and totally trashed props than gear
boxes that failed due to prop strike. The gears are a lot more rugged
than you would think. Remember that there is a friction clutch in the
system that will give some under an extreme shock load.

--

Roger Long



"Skip Gundlach" skipgundlach at gmail dotcom wrote in message
...
Hi, Lists,

Thanks for all the responses to my line cutter question. To put one on
will require some more space, and, in general, I've come to think that a
break-away (with built-in safeguards to allow continued use until
replacement) spacer is also a good move.

Who here has had one, and, best, has had to use it to save their gear?

Thanks again.

L8R

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

"Twenty years from now you will be more disappointed by the things you
didn't do than by the ones you did do. So throw off the bowlines. Sail
away from the safe harbor. Catch the trade winds in your sails. Explore.
Dream. Discover." - Mark Twain

Drive Saver/Spacer users sought
 

I would just put in a very accurately machined spool piece or steel
disk with proper pilots. As I understand it, having just had the
opportunity to sit at the feet of some masters and listen but not
being an expert myself, the really critical alignment issue is that
the shaft be exactly centered. Steel will do this better than
plastic. Bolts will not maintain it reliably. You need those
machined pilots.

I know that the drivetrains I have used so successfully must develop
some angular misalignment as the engine moves around on the mounts but
the shaft accommodates it without a problem. The single stern bearing
and flexible stuffing box (or shaft seal) on these boats is actually
almost exactly the same setup as on many sailboats.

If you are relying on something between the flanges to accommodate
misalignment, it has to be very, very, soft. Otherwise, there will
still be enough force transmitted to create vibration. Just think how
hard it is to dent or deform that drivesaver disk even a small amount
and then imagine that force on your system a few hundred times a
minute. If the coupling is soft enough to accommodate misalignment,
then you will need a thrust bearing and all sorts of other
complications. I've designed and built successful shaft lines for
auxiliary equipment with big rubber tire couplings, CV joints and
thrust bearings, etc. None ran a smoothly as these high power
research vessels do.

Say, I'm awake too early, how about a sea story?

I worked at Woods Hole Oceanographic Institution converting the ship
that Bob Ballard later used for the first mapping of the Titanic site
and the Alvin dives to the ship. We were taking out the steam engines
and installing a diesel power plant. We took two of the propulsion
motors out of the old diesel electric salvage tug "Chain" the was in
the process of being scrapped and turned them into DC generators to be
driven by big PTO's on top of the new reduction gears. One of my jobs
was to design the shaft system which had to penetrate the main
watertight bulkhead just aft of the reduction gears.

My boss wanted to build two tall pedestals with pillow blocks to
support the shafts. It would have been really tight and complicated
and alignment very critical with the bearings so close to each other.
I suggested that we just let the ends of the shaft hang on it's own
bearings by modifying a big rubber tire flex coupling at the generator
end with a pilot bearing inside. My boss explained that there were
buoys down south of Cape Horn that the ship had to retrieve before the
batteries in the acoustical locator beacons and anchor releases ran
down. If my idea didn't work, years of research would be down the
tubes and several Ph.D. candidates might have to spend and extra year
or two in school to get their doctorates. Was I sure? I was pretty
young but I gulped and said, "Yes".

"What did you say?", he asked, "I couldn't hear you."

"YES"

So, I designed the rig. Time and people were short so I ended up
assembling it myself. The engines for the ship were two surplus
railroad locomotive engines that came from a Navy warehouse still
wrapped up from 1942. Finally, the day came to fire things up and
test it.

We clutched in the port generator. It ran beautifully. Then we
started up the identical starboard engine and clutched in the PTO.
Instantly, the six foot diameter generator and twelve foot long engine
started violently lunging back and forth so hard that you could almost
see the structure of the ship deform. We stopped everything
instantly. Took it all apart, checked the alignments, put it back
together. Same result. Everyone was spending a lot of time staring
at me.

We checked and rechecked. We tried to reproduce the problem on the
other side. It was a total mystery. Finally, my boss said that there
was only one guy who could figure it out and flew someone up from
Texas. The Texan arrived and we fired it up for him so he could watch
the whole thing thrash around. This is tons of machinery solidly
bolted to the heavy engine bed of a ship shaking it so you feel like
you are standing in a moving train. Very scary.

He watched for two seconds and yelled, "Shut it off!". Then he
jumped up on the engine and opened up the cover of the engine
governor. "Give me a drill.", he asked. He drilled a hole, did
something else, put the cover on, and told us to start it again. It
ran smooth as silk and both sides continued to for years until the
ship was sold.

Turns out that the governor of the starboard engine had a device in it
that would give the engine a little boost of power if it suddenly
slowed down. This is so that it wouldn't stall when the locomotive
took all the slack out of the couplers when starting up the train.
When we clutched up the PTO, the inertia of starting the big generator
would wind up the rubber tire coupling and slow the engine. The
governor would give it a goose winding up the coupling some more. The
coupling would then unwind, unloading the engine. The timing was such
that these impulses would travel back and forth through the system in
such a way as to amplify each other with each cycle and build up to
enormous force in about two seconds. All the guy did was drill a hole
and drop a pin into the boost mechanism of the governor. He was on
the ship for ten minutes and then in his car headed back to the
airport.

The next day, we tied pulling power from the generator. The other one
had worked fine so this was pretty casual. When the switch was
thrown, a ring of fire, like a circular lightning bolt appeared around
the commutator of the big, open frame, motor cum generator. I'd
always wondered whether those little round escape hatches in ships
were big enough but, six guys can go up a ladder and through one in
less than three seconds when sufficiently motivated.

Turns out that the guy who overhauled the motor put the brushes in
backwards. He came down and turned them around. No harm done and the
whole system worked perfectly thereafter.

--

Roger Long



"Skip Gundlach" skipgundlach at gmail dotcom wrote in message
...
Hi, Roger, and List/Group,

This really has more to do with a spacer than drive saver, though I
like the flexibility of it in case the alignment isn't perfect.

Those of you who have been around a couple of years know how we
jacked the tranny out of the mounting plate (now replaced, no harm
done other than inconvenience in making up a keeper to stay moving
with the engine, and the packing gland needing redoing cuz of the
weight of the tranny on the shaft when it came out, also redone).
Recent readers also know of my search for line cutters, which would
have prevented that (which shouldn't have happened, but stupid
sailor tricks happen all the time, anyway, so a mooring line
overboard isn't guaranteed against for all time on our boat, as much
as we'd like to think so, and, of course the occasional lobster/crab
pot warp I don't see in the middle of the night) - which will
require a longer shaft, or...

... a spacer - so why not a flexible one?

And, I was looking for input from those who'd had a use for one
preferably where the thing sheared and left the 'limp home' mode in
place.

I agree about proper alignment - and that will happen before we
insert a spacer or drive saver...

L8R

Skip, back to the boat for two weeks in a few days


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

"Twenty years from now you will be more disappointed by the things
you
didn't do than by the ones you did do. So throw off the bowlines.
Sail
away from the safe harbor. Catch the trade winds in your sails.
Explore.
Dream. Discover." - Mark Twain
"Roger Long" wrote in message
...
For what it's worth, I deal often with one of the foremost
drivetrain and propulsion specialists in the country in connection
with designing boats like this:

http://home.maine.rr.com/rlma/WHOIrv.htm

The shipyard that builds these boat specializes in fast,
sophisticated, high powered craft. Both told me that they hate
"Drivesavers". The boat in the picture has two 710 horsepower
engines with the engines flex mounted and the shafts connected with
solid couplings. There is just one bearing, in the shaft strut.
They run smooth as silk.

I do have a drivesaver disk in my boat but they cut the shaft short
when they installed it so I have to buy a whole new shaft to take
it out. It's not causing any problems that I can see though other
than making it a pain to repack the stuffing box.

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.

There's a whole range of prop strike forces where the drive saver
could break but the solid coupling would still leave you able to
limp off a lee shore with the engine vibrating and shaking. I like
that scenario better. I've heard of a lot more broken shafts and
totally trashed props than gear boxes that failed due to prop
strike. The gears are a lot more rugged than you would think.
Remember that there is a friction clutch in the system that will
give some under an extreme shock load.

--

Roger Long



"Skip Gundlach" skipgundlach at gmail dotcom wrote in message
...
Hi, Lists,

Thanks for all the responses to my line cutter question. To put
one on will require some more space, and, in general, I've come to
think that a break-away (with built-in safeguards to allow
continued use until replacement) spacer is also a good move.

Who here has had one, and, best, has had to use it to save their
gear?

Thanks again.

L8R

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

"Twenty years from now you will be more disappointed by the things
you
didn't do than by the ones you did do. So throw off the bowlines.
Sail
away from the safe harbor. Catch the trade winds in your sails.
Explore.
Dream. Discover." - Mark Twain

Drive Saver/Spacer users sought
 

"Roger Long" wrote in message
...
I would just put in a very accurately machined spool piece or steel disk
with proper pilots. As I understand it, having just had the opportunity to
sit at the feet of some masters and listen but not being an expert myself,
the really critical alignment issue is that the shaft be exactly centered.
Steel will do this better than plastic. Bolts will not maintain it
reliably. You need those machined pilots.

I know that the drivetrains I have used so successfully must develop some
angular misalignment as the engine moves around on the mounts but the
shaft accommodates it without a problem. The single stern bearing and
flexible stuffing box (or shaft seal) on these boats is actually almost
exactly the same setup as on many sailboats.

If you are relying on something between the flanges to accommodate
misalignment, it has to be very, very, soft. Otherwise, there will still
be enough force transmitted to create vibration. Just think how hard it
is to dent or deform that drivesaver disk even a small amount and then
imagine that force on your system a few hundred times a minute. If the
coupling is soft enough to accommodate misalignment, then you will need a
thrust bearing and all sorts of other complications. I've designed and
built successful shaft lines for auxiliary equipment with big rubber tire
couplings, CV joints and thrust bearings, etc. None ran a smoothly as
these high power research vessels do.

Say, I'm awake too early, how about a sea story?


Marvelous story, Roger,

Back to mine, however, the spacer is just between a couple of flanges, both
flat on the mating surfaces, with no pilot or other bearing or bushings or
pins. If the shaft and the tranny plates aren't perfectly aligned fore-aft,
they aren't going to want to go together. Twiddling, if needed, the engine
mounts will take care of any minor differences (I'm into tight tolerances -
I think .005 or less? might do it). Whenever it was converted from bronze
to SS shaft, the intermediate bearing was removed (still aboard, but would
require removing the Max prop and flange and pulling the shaft far enough
for remounting. As it made it for however many years it was from the change
to now, successfully, it's my presumption that it wasn't needed any more,
perhaps due to the greater rigidity of the SS over the original bronze.

I understand and "get" what you are saying about the drivesavers - but years
of use by others, successfully, makes me wonder why the problems you
cite/project don't make it so nobody uses them?

I also don't "get" what you are saying about spool piece or pilot - I need a
spacer of some sort to accommodate the line cutter. If I wanted to save a
bunch of money (having to buy it originally; there may be one in my cockpit
when I get there from someone who had it available, and if it fits, it's
cheap), I'd just get the proper thickness scrap steel machined to fit the
proper size and holes, easily enough done by a rubbing of both pieces, I'd
think. (Curiously to me, some of the line cutter folks want several
hundred - as much as the device - for their machined steel spacer...)
However, if I align it first, then slide it aft only enough to use the
spacer (whatever it is), should not that alignment persist through the use
of - the only difference I'd see - longer bolts? Of course, I'd check,
using the modus recommended by DriveSaver, if that turns out to be what I
use, but I'd expect that it would come out right.

Thanks for your insight(s) - and thanks again for the story, as well as
getting to see your Titanic thoughts.

L8R

Skip


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

"Twenty years from now you will be more disappointed by the things you
didn't do than by the ones you did do. So throw off the bowlines. Sail
away from the safe harbor. Catch the trade winds in your sails. Explore.
Dream. Discover." - Mark Twain

Drive Saver/Spacer users sought
 

"Skip Gundlach" skipgundlach at gmail dotcom wrote

I understand and "get" what you are saying about the drivesavers -
but years of use by others, successfully, makes me wonder why the
problems you cite/project don't make it so nobody uses them?

They aren't really a problem by themselves but sort of a band aid
solution for not doing it right in the first place. Of course, most
pleasure boaters, and plenty of boatbuilders, don't want to do it
right. They just want to take stuff out of boxes and bolt it
together. A drivesaver probably won't make things any worse in that
situation, it may even help a little bit with a boost from the placebo
effect.

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.
A male/female pilot or disk; not the bolts, keeps the two halves
concentric.

If you're not going to do this stuff, maybe a drivesaver will help but
it won't be as good as doing it right.

If you do it right, you won't need the drivesaver and it just makes
things more likely to slip.

Still, I wouldn't bother taking the one out of my shaft system except
to make it less of a pain to repack the stuffing box.

--

Roger Long

Drive Saver/Spacer users sought
 

In article ,
"Roger Long" wrote:

"Skip Gundlach" skipgundlach at gmail dotcom wrote

I understand and "get" what you are saying about the drivesavers -
but years of use by others, successfully, makes me wonder why the
problems you cite/project don't make it so nobody uses them?

They aren't really a problem by themselves but sort of a band aid
solution for not doing it right in the first place.

Sorry if I'm misinterpreting -- it's late and I'm catching up on 1400
messages -- but my post seems to be the genus of this.

Our Drivesaver is solely there to try to protect the engine and drive
shaft in the case of a wrapped mooring line or similar. We snapped a
shaft once. I only mentioned that it helped moderate vibration as a
slight benefit.

Every couple of years, I take the drivesaver out, check the alignment
and would correct if necessary, but it hasn't been.

BUT with the Yanmar's flexible mounts, there will be some misalignment
under some power loads, merely because the engine has shifted in its
mounts slightly due to torque.

I wasn't talking about the vibrations a 700 HP setup would generate. I
was talking about vibrations a sailor would notice, one who spent about
70 days out and about last season and who used a grand total of 13
gallons.

I may be hyper-sensitive to noise and vibration, but the drivesaver
makes my motoring time more enjoyable.... Okay, less objectionable.

--
Jere Lull
Xan-a-Deux ('73 Tanzer 28 #4 out of Tolchester, MD)
Xan's Pages: http://members.dca.net/jerelull/X-Main.html
Our BVI FAQs (290+ pics) http://homepage.mac.com/jerelull/BVI/

Drive Saver/Spacer users sought
 

"Jere Lull" wrote

I may be hyper-sensitive to noise and vibration, but the drivesaver
makes my motoring time more enjoyable.... Okay, less objectionable.

I have no doubt that it does. My point was that setting up everything
PROPERLY would very likely produce an even smoother running system.
The key word is properly. Few boats have their shaft systems machined
properly which makes a good market for the Drivesaver. At least this
is the opinion of the people who have set up the demanding drive
trains in my 1400+ HP boats so they run far smoother than my sailboat.

Doing it right probably would cost quite a bit more than a drivesaver
which may also help keep those folks in business.

One thing I hadn't thought of:

The shafts on the boats I'm used to dealing with are very
conservatively designed and I've almost never heard of one breaking,
even when the wheels are totally trashed. With the small shafts
common on many yachts, it might make sense to have a "fuse" in the
system that is cheaper than the shaft.

I'll have to confess that I don't deal with the nitty gritty details
of shafts; just the basic layout and sizing. I'm simply passing on
what a guy who has solved shaft problems that others couldn't on boats
from fast patrol boats to aircraft carriers told me when I said,
"shouldn't we have a Shaftsaver?"

I'm sure opinions vary. The shaft shop you talk to may love to just
take stuff out of boxes and sell it to you alone with a Shaftsaver for
the same price as doing it the right way. They may not even know the
right way in which cast the Shaftsaver is your best option.

Like I said, taking the one out of my shaft line is about item number
6374 on my list of things I'd like to do.

--

Roger Long

Drive Saver/Spacer users sought
 

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

Drive Saver/Spacer users sought
 

"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

Drive Saver/Spacer users sought
 

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

Question followup for Roger (was) Drive Saver/Spacer users sought
 

"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."

Question followup for Roger (was) Drive Saver/Spacer users sought
 

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."

Drive alignment (was) Drive Saver/Spacer users sought
 

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

Drive Saver/Spacer users sought
 

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.

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

Drive alignment (was) Drive Saver/Spacer users sought
 

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

Drive alignment (was) Drive Saver/Spacer users sought
 

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

Drive alignment (was) Drive Saver/Spacer users sought
 

"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

Drive alignment (was) Drive Saver/Spacer users sought
 

Yikes!

This is a bullet you'd really better bite and have the whole thing
checked out. You should be working with a feeler gauge when checking
final clearances around the flanges. It should be rechecked after the
boat is launched just for hull flex.

Get it right now. It will never be easier or cheaper.

BTW there is a way you can check the shaft coupling in the boat but it
takes some rigging and doesn't tell you about other things that should
probably be checked with the kind of history you relate.

--

Roger Long