Skip Gundlach" wrote

However, I'm baffled, given your prior assertions, that you don't
eliminate the issue by using a solid spacer, as I'm, based on your
scholarly treatise on the subject, going to do.

Good point and touched on in a reply above. Worth expanding on.

I was reporting what the most knowledgeable driveline people I've met
told me. Looking at better pictures of the unit at the link that Evan
sent, I find it a bit harder to understand why they feel that way. My
discussions with them involved engines of 35 times the horsepower
which may bear significantly on the issue.

I still think my boat (and yours) would end up smoother with a solid
coupling and everything trued up as I recommend you do but it is
acceptably smooth to me now. I wouldn't at this stage of refit and
finances, pay for a spacer and all the other machining just to make it
a little quieter. I'll probably do all that before I head off to
Newfoundland in a few years but my priority now is to not find myself
sinking because the stuffing box hose let got while also avoiding
divorce because of the bills. Either would probably result in loss of
the boat.

I also have a wicked clearance issue that makes packing the stuffing
box almost impossible and would much rather invest in the proper
length shaft than a spacer. One thing prompting this is the discovery
that there is only room for one hose clamp on the stern tube. I think
it's long enough but someone lapped the glass on top too much and
covered up part of it. I think I can cut that back but I'll need a
new hose to get enough length for the second hose clamp. Sliding the
hose back enough to pull the coupling bolts is not an option.

--

Roger Long

Did you read the article on alignment I cited? It's by a primarily
high-end powerboat surveyor, so has that bias.

The best I can read out of his stuff is that alignment in our boats
isn't worth much...

Despite that, I''m still going to pull the tranny, the shaft, take off
the prop (of course, required) and take the couplings and shaft off for
truing, should it need it. Another list I'm on where a similar
discussion is taking place has it that the only reliable
truing/observation of a shaft is a calibrated roller bed. His (the
surveyor) article suggests it's not needed in our sizes, based on all
the other factors...

L8R

Skip

Morgan 461 #2
SV Flying Pig KI4MPC
http://tinyurl.com/p7rb4 - NOTE:new URL! 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

I haven't had a chance to read it yet due to the rare opportunity to
actually earn a little money.

He may well be right. When I stop and think how stubborn and
difficult vibration issues are in high powered boats and how rare
problems are in almost universally neglected drive trains like ours, I
can believe it.

The shaft on one of my research vessels is about 3" dia. Three times
the diameter for over 30 times the horsepower so the relationships are
quite different.

You've got my curiosity up so I think I'll take a break....

You'll feel better after you do all that work anyway

--

Roger Long



"Skip Gundlach" wrote in message
oups.com...
Did you read the article on alignment I cited? It's by a primarily
high-end powerboat surveyor, so has that bias.

The best I can read out of his stuff is that alignment in our boats
isn't worth much...

Despite that, I''m still going to pull the tranny, the shaft, take
off
the prop (of course, required) and take the couplings and shaft off
for
truing, should it need it. Another list I'm on where a similar
discussion is taking place has it that the only reliable
truing/observation of a shaft is a calibrated roller bed. His (the
surveyor) article suggests it's not needed in our sizes, based on
all
the other factors...

L8R

Skip

Morgan 461 #2
SV Flying Pig KI4MPC
http://tinyurl.com/p7rb4 - NOTE:new URL! 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

Just skimmed it.

I think he's right but he's talking about something different than the
couplings faces being true and square to the shaft. If you have a
true running shaft pulled out of line by the engine moving on the
mounts or not being perfectly aimed towards the strut, that's one
thing and probably not a big issues as he says. If the engine is
trying to wave the far end of the shaft in a circle under the same
circumstances, I think you are going to have some noise.

--

Roger Long

Roger Long wrote:
Skip Gundlach" wrote

However, I'm baffled, given your prior assertions, that you don't
eliminate the issue by using a solid spacer, as I'm, based on your
scholarly treatise on the subject, going to do.


Good point and touched on in a reply above. Worth expanding on.

I was reporting what the most knowledgeable driveline people I've met
told me. Looking at better pictures of the unit at the link that Evan
sent, I find it a bit harder to understand why they feel that way. My
discussions with them involved engines of 35 times the horsepower
which may bear significantly on the issue.

I still think my boat (and yours) would end up smoother with a solid
coupling and everything trued up as I recommend you do but it is
acceptably smooth to me now. I wouldn't at this stage of refit and
finances, pay for a spacer and all the other machining just to make it
a little quieter. I'll probably do all that before I head off to
Newfoundland in a few years but my priority now is to not find myself
sinking because the stuffing box hose let got while also avoiding
divorce because of the bills. Either would probably result in loss of
the boat.


By the way, in my business we really like Lo-Rez mounts / couplings as
they are considerably softer (and thus transmit less vibration) than
rubber or elastomer mounts and couplings. And we use them on 5000 HP
tugs all the time.

I also have a wicked clearance issue that makes packing the stuffing
box almost impossible and would much rather invest in the proper
length shaft than a spacer. One thing prompting this is the discovery
that there is only room for one hose clamp on the stern tube. I think
it's long enough but someone lapped the glass on top too much and
covered up part of it. I think I can cut that back but I'll need a
new hose to get enough length for the second hose clamp. Sliding the
hose back enough to pull the coupling bolts is not an option.

Having a similar situation on my last boat you have my sympathy.
Getting the packing out of the stuffing box required the use of a fish
hook that had been straightend out and held with some needle nose vise
grips.

Evan Gatehouse

I got the coupling separated. The gear flange attachments on these
small Drivesavers appear to be molded in studs. The nuts on them were
thoroughly rounded and buggered up when the unit was installed so it
probably isn't coming off the gear unless the engine comes out of the
boat.

Picture here and more info he

Http://home.maine.rr.com/rlma/Strider0605.htm#Latest

--

Roger Long