GL: How do I stop rotation on a 2.5 inch shaft

[Joseph Roy]

Once I needed to motor a long distance with only one engine. I had no good idea how to stop the idled shaft from turning while I idled my way back to port. Can anyone provide clear instructions on how to tied a shaft down, or is there a mechanical device available to do this?


I would appreciate all suggestions,


Joe


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[Ralph Yost]

Large pipe wrench or large vice grips. Clamp on the shaft and let the wrench
handle rest on the hull to counter the rotation. It WILL gouge up the
shaft....but so what?
They sell elaborate devices that look like a car brake system with a caliper
and clamp on the caliper but I don't think its worth it unless you are doing
it often.
R.

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[Sean Welsh]

On 02/09/2017 08:43 PM, Joseph Roy wrote:
> Once I needed to motor a long distance with only one engine. I had no good idea how to stop the idled shaft from turning while I idled my way back to port. Can anyone provide clear instructions on how to tied a shaft down, or is there a mechanical device available to do this?

Yes, there are shaft lock or shaft brake devices. However, first I would
ask whether it is even necessary.

When we were boat shopping, any time we looked at a twin I researched
the make and model of transmission to see if it could be freewheeled. A
surprising number of them can be freewheeled without issue; some can be
freewheeled for short periods or below certain speeds, and some can be
freewheeled if the fluid is circulated with a pump. Stuffing boxes are
another issue of course; some dripless seals will require an external
water supply, at least above certain speeds.

Unless your transmission is not permitted to freewheel at all, you can
likely come up with a strategy to operate without locking the shaft. And
on some transmission/engine combinations, stopping the rotation may be
as simple as putting it in gear.

Quick story: While we were very careful to do this research for
twin-engine boats (on the theory that we'd cross oceans on a single
engine, alternating periodically), when we ended up with a single screw
boat, we neglected to check. And so it was that one day in the middle of
the night we awoke in panic to the sound of the propeller windmilling in
Winyah Bay, as perhaps as much as three knots of current passed under us
after a tide change. We started the engine to circulate fluid until we
could figure it out; after about an hour of research we learned there
were no restrictions on freewheeling our ZF transmission.

-Sean
m/y Vector
lying New Orleans, LA
http://OurOdyssey.BlogSpot.com

[John Esch]

While doing the Loop I stopped the shaft a few times with a rope tied to
the engine mount on one end and the other eye spliced end looped a few
time around the shaft and over a coupling bolt. Some other people used a
piece of wire the same way. Once i spun the shaft by hand to tighten up
the line it stayed in place.

John Esch
Fet-Esch, currently lying Port St Lucie, FL

[Rich Gano]

And then there is the pre-GPS story of the guy who needed to economize of
fuel to make it and who removed one of his propellers and set off for Hawaii
from the west coast keeping an eye on the jetliner contrails, and when he
got halfway there dove to replace the prop and remove the original to even
out engine wear.

One thing that was discussed here long time back was the difference in
resistance between a freewheeling prop and a locked-in-position prop. That
was interesting.


Rich Gano
FROLIC 2005 Mainship 30 Pilot II
Panama City, FL

[Phil Little via Great-Loop]

From: Ralph Yost <ra...@alphacompservices.com>
To: 'Joseph Roy' <jor...@hotmail.com>; great...@lists.trawlering.com
Sent: Friday, February 10, 2017 6:33 AM
Subject: Re: GL: How do I stop rotation on a 2.5 inch shaft

"Large pipe wrench or large vice grips. Clamp on the shaft and let the wrench
handle rest on the hull to counter the rotation. It WILL gouge up the

shaft....but so what? " Snip.
Not a good idea. A stress concentration will be introduced which can lead to low-cycle fatigue failure depending on torque level. And yes, it will fall off as soon as the shaft momentarily reverses itself, such as while rolling in the troughs while stationary.
I think the easiest solution would be to affix one or more eyes to the shaft coupling bolts, and a short chain with a hook, attached to the hull, could just be hooked in, or be quickly attached if the shaft is jerking around while away from the dock.
FWIW, most modern marine gears drive the hydraulic pump, for lube and clutch application, off the input shaft, so no lube flow with a stopped engine, The frictional heat generated by windage and clutch plates rubbing, and lack of cooler flow, can cause the lube temperature to rise. 220 deg. F, is the point at which most gear lubes lose film strength, and metal-to-metal contact ensues. Death! $$!
Since the lube oil temperature sensor is probably in a flow path, it will not correctly indicate lube bulk temperature, and certainly not elevated temperatures at teeth-mesh surfaces and bearing races.
I've seen a common problem on 4- and 5-engine GOM crew boats, losing an engine underway, certain (unnamed mfg.) equipped boats actually had a wheelhouse plaque stating DO NOT FREEWHEEL. Then the crew had to somehow secure the shaft, whipping back and forth while possibly rolling violently in a beam sea. This impossible situation led to a lot of ruined transmissions. Lose the gear, not an arm!
In summary, after working at a marine gear manufacturer, especially on a project to develop a portable QD-attached auxiliary lube pump for freewheeling use, my advice would be not to freewheel if avoidable.  
Phil Little

[Robert Austin]

I have sailed many thousands of miles with the shaft locked using “Chain Vise Grips” Chain Vise grips, use a 18” motor cycle type of chain and cost about $35. The chain Vise Grips have all sorts of uses around the boat—especially when a strap wrench will not do the job! There are cheap imitation—but as usual one gets what he pays for.

Example: https://www.lowes.com/pd/IRWIN-Vise-Grip-Chain-Clamp-Locking-Pliers/50431790 <https://www.lowes.com/pd/IRWIN-Vise-Grip-Chain-Clamp-Locking-Pliers/50431790>

I had a block of 2/4 for the Vise Grip handle to rest upon. A lot depends on the configuration of the hull, if this short handle will do the job, It did in sail boats 46 to 62 feet long. However, the prop was only a 3 blade 24” diameter.

I wonder what type of vice, one is stopping? Probably one of the most often misspelled tools!

Regards,

Bob Austin
Pensacola, FL.

[Norm Miller]

On my boat if I clamp a pipe wrench on the prop shaft it would cause damage that would make changing a PSS seal an ordeal so I would never do it. Maybe a strap wrench on the engine coupler.

First determine if you boat can operate with a shaft rotating with no problem.

Norm Miller
Quiet Company
Great Harbour GH47


Sent from my iPad. Please excuse typing errors...

[PeteandPeggy]

In ref to your problem of stopping a marine prop shaft from rotating,
identify the direction of rotation of your shaft. Then select a dock
line of about 5/8" . If you have a large set screw or bolt that you can
secure to on the coupling from the engine, secure this line to same, and
then find a good substantial item to secure the other end of the line.
You might also make a few turns around the shaft before making the final
attachment to the boat. I like to make a bunch of clove hitches if no
bolt is available- say 10 - 15 hitches around the shaft.

I have used this set up to stop the shaft for two reasons- some of the
dripless seals will burn up after 20 or so minutes and some marine
transmissions will over heat due to lack of oil and no cooling.

Pete


>> *From:* "Ralph Yost" <ra...@alphacompservices.com
>> <mailto:ra...@alphacompservices.com>>
>> *Date:* February 10, 2017 at 6:33:49 AM EST
>> *To:* "'Joseph Roy'" <jor...@hotmail.com
>> <mailto:jor...@hotmail.com>>, <great...@lists.trawlering.com
>> <mailto:great...@lists.trawlering.com>>
>> *Subject:* *Re: GL: How do I stop rotation on a 2.5 inch shaft*
>> *Reply-To:* Ra...@alphacompservices.com
>> <mailto:Ra...@alphacompservices.com>