Cardude close call on crossing

[psneeld]

Vomit may work well when dried.... though it mat be a bit corrosive if any former Rum was mixed in.

 

[skyhawk]

Seen that happen a bunch of times. Coupler bolts shearing. Most common on boats with tight access to that area where the last tech could not (or did not) get enough purchase on the bolts/nuts to get enough torque on them. Can hear the muttering "good enough". A few years later, it was not "good enough".

Gotta put the hoodoo on those grade 8 bolts/nuts. Whatever it takes, wrench-wise.

I'd imagine there aren't very many boats with accurately aligned shafts either... a hard adjustment to make I'd guess in most boats...+ the rotational speed is slow enough for it to "seem" forgiving of misalignment....

 

[healhustler]

Vomit may work well when dried.... though it mat be a bit corrosive if any former Rum was mixed in.

LOLROF! If I know Bill, chemical analysis would reveal that it was definitely a cocktail of contents. Past experience has shown me that the Dude is not shy on “splicing the mainbrace”.

 

[Gdavid]

View attachment 123017

We made it to the dock with my temp repair. I need to go search for some good grade 8 bolts today. What about putting loctight on them?

I do have a sail rig, and the sails were up when this happened. If I was not able to fix the coupler that was my plan, but it would have taken forever to sail in, and I’m not sure I could have sailed through that inlet. We were about 70miles from Pensacola when it happened and it was pretty rough IMO.

A drogue would have been nice to keep the bow into the waves. 3-5’ swell and all that wind chop hitting the boat on the beam really sucked. It was too deep to anchor.

Glad to hear you are back in port safely. Have you ever tried heaving to with your sailing rig? Do you know if the PY and SP models have the same rudder?

On most well balanced rigs, once you are hove to, you can adjust your relative angle to the wind (to a degree) by adjusting the main.

 

[fgarriso]

High strength bolts needed perhaps ?

Safety wire and Loctite on prop shaft bolts!

 

[cardude01]

Glad to hear you are back in port safely. Have you ever tried heaving to with your sailing rig? Do you know if the PY and SP models have the same rudder?

On most well balanced rigs, once you are hove to, you can adjust your relative angle to the wind (to a degree) by adjusting the main.

I have not tried to heave to yet. This is such a small sail rig I kind of doubt it would work, but I should try it I suppose.

 

[HTurner]

I have not tried to heave to yet. This is such a small sail rig I kind of doubt it would work, but I should try it I suppose.

It will work...

 

[High Wire]

Curious to what grade bolts were in place that broke. Can you post a pic of the bolt head?

 

[cardude01]

In spite of that. Welcome to FLORIDA.

My only comment. IF the bolt doesn't see much length to stretch, just relying on torque alone may be risky. LW and blue locktite for me.

Consider a connecting rod assembly. Typically, no locktite or LW on those, just a correctly torqued nut, and look what horrific action it is subjected to. But, its on a long, stretched bolt.

These shaft/trans coupler bolts on my boat are not very long at all due to the lack of clearance. Maybe 2”? I agree on the locktite and lock washers.

 

[wkearney99]

Had that happen on a previous boat, a 34' that had twins w/v-drives. Thankfully not in bad weather. Caught the vibration right away, locked off the shaft from turning with some vise grips and used the other engine to get home. Spares kit onboard now always includes those bolts AND the tools necessary to attach them.

 

[BruceK]

Glad it worked out. Maybe nyloc nuts plus tab washers. Wouldn`t lock wiring need a hole drilled into the bolt? Same goes for castellated nut and split pins.

 

[kthoennes]

Even though our boat is shrink wrapped and on jackstands until April, this conversation is making me want to jump in the car and check my bolts.

 

[catalinajack]

I had the same happen while in the sixth lock in Ottawa. Imagine my surprise as I am moving forward into the next lock and losing propulsion. Fortunately, I have twins and was able to use the other engine to check my forward motion but it took a few moments to realize what was happening and bring the off-engine to bear. I came pretty damn close to the lock gate.. Turns out that two of the four coupler bolts had disappeared into the bilge. With only two remaining, the wobbling resulted in the bolts to the DriveSaver intercoupling being ripped out of the hard plastic/rubber thus parting the shaft from the transmission.

Yes, I now often take a look at my coupler bolts. It happened cuz of a lousy job by the yard who replaced my damper plates. Instead of using fresh bolts and lock washers, they reused the old, tired bolts. I found that the nuts on the two remaining bolts were only finger tight. I have always been suspicious that the mechanic neglected to do the final tightening of all four nuts. He may have run them to finger tight and then plain forgot. No way of knowing.

 

[O C Diver]

I'm very happy that Jewel and Bill are safe!

But, after the near demise in the Bahamas and now this, one has to wonder about the Karma of putting a sailing rig on a power boat. Just saying....

Ted

 

[healhustler]

I'm very happy that Jewel and Bill are safe!

But, after the near demise in the Bahamas and now this, one has to wonder about the Karma of putting a sailing rig on a power boat. Just saying....

Ted

Exactly, Ted, and I’ve been trying to get Bill to install some Ft Lauderdale sized neuticles, an antenna farm, and a tuna tower to offset these blatant “light side” accessories and get some respect around here.

 

[HopCar]

Cardude glad it worked out. Sounds scary.

This conversation got me to wondering what coupling manufactures recommend for bolts. I went to the Buck Algonquin catalog and found they sell Coupler Flange Bolt Sets. The sets include Grade 5 bolts, nuts, and split lock washers. They are not drilled for safety wire or cotter pins.

They also had metric sets which were Grade 8.8. I don’t know what that is.
Cardude we’re the nuts still on the broken bolts?
Could you tell if the bolts failed in tension or shear?

I’m not an engineer but I would think that if there was an alignment problem the bolts might fail in tension. If the nuts were not properly torqued it might allow the flanges to work back and forth causing shear. I won”t be offended if someone smarter wants to correct me on this.

 

[rslifkin]

Metric Grade 8.8 is approximately equivalent to SAE grade 5.



This makes me think I should check my coupler bolts at some point before we launch in the spring. And more importantly, I should make sure I have some spares. I have the tools to install them, but I'm not sure I've got spare bolts in the right size. If I'm remembering correctly, mine are installed with split lock washers under the nuts.

 

[cks]

Every year.
I check every bolt.
Before every days run I am in my engine room to take a quick survey.
Every time……

 

[Ski in NC]

No need for locktite or lockwire or castellated nuts w/pins.

Standard kit for couplings (SAE) is fine thread bolts, nuts and lockwashers, all grade 8. If you can't find grade 8, grade 5 will do, but I would replace with gr 8 when you can get them in hand.

I have seen two types of coupling bolt failures: Nuts coming off and bolts fracturing. The root cause of both is the same. Insufficient torque. Nuts can work off and be shed. Or when running loose, normal torsional variations from the diesel will cause relative motion between the flanges and that will flex and fatigue the bolts, leading to fracture.

A properly made up flange joint will have zero relative motion, bolts will stay tight and you will have zero problems.

Cardude- Consider pulling back the prop shaft and checking flanges around bolt holes for "raised metal". This can screw up alignment and can be fixed with a file. You want the flanges to mate up absolutely flat, and not be kicked apart by damage around a bolt hole.

Good time to do an alignment check too.

 

[cardude01]

I'm very happy that Jewel and Bill are safe!



But, after the near demise in the Bahamas and now this, one has to wonder about the Karma of putting a sailing rig on a power boat. [emoji57] Just saying....



Ted

Or, it could be that I’m just a general dumbass. ?

Here is the last remaining bolt that was trying to hold the thing together. If you look closely the threads are smashed in the middle.





I had the transmission replaced on this boat a few years ago and I think they reused the same bolts, so I’m assuming this is the OEM bolt. Hard to see in the photo but this is a 10.9 grade bolt.

 

[diver dave]

Well shoot. U got a metric bolt set on a FL built boat. [emoji848]

kidding aside.

A M10 is smaller than a 7/16" by about 40 thou.

Can't tell what you have, but a slightly smaller dia bolt will have more play than the design wants. Play is bad here.

 

[O C Diver]

Don't know if you can find them, but I prefer bolts where there is smooth shank in both flanges instead of thread.

Ted

 

[angus99]

I had the transmission replaced on this boat a few years ago and I think they reused the same bolts, so I’m assuming this is the OEM bolt. Hard to see in the photo but this is a 10.9 grade bolt.

Could be worse, Bill. They could have left the bolts off entirely, like a PO (or whoever he hired) did on my boat. As we were preparing to have damper plates replaced a few years ago, we noticed the Twin Disc on the starboard side budging ever so slightly whenever it was shifted in or out of gear. Upon disassembly, it turned out that FIVE (!) of the seven bolts supposed to be holding the tranny to the adapter plate were missing. These were not visible from the outside, so it was not possible to know they were AWOL without removing the Twin Disc. Nothing laying in the bell housing; they were simply never installed. Evidently, the weight and torque were being shouldered by some combination of the splined shaft, the prop shaft, some guide pins and the two bolts.

Glad you made it back safely.

 

[healhustler]

Upon disassembly, it turned out that FIVE (!) of the seven bolts supposed to be holding the tranny to the adapter plate were missing. These were not visible from the outside, so it was not possible to know they were AWOL without removing the Twin Disc. Nothing laying in the bell housing; they were simply never installed. Evidently, the weight and torque were being shouldered by some combination of the splined shaft, the prop shaft, some guide pins and the two bolts.

Holy crap!

 

[Max1]

View attachment 123017

We made it to the dock with my temp repair. I need to go search for some good grade 8 bolts today. What about putting loctight on them?

I do have a sail rig, and the sails were up when this happened. If I was not able to fix the coupler that was my plan, but it would have taken forever to sail in, and I’m not sure I could have sailed through that inlet. We were about 70miles from Pensacola when it happened and it was pretty rough IMO.

A drogue would have been nice to keep the bow into the waves. 3-5’ swell and all that wind chop hitting the boat on the beam really sucked. It was too deep to anchor.

Glad you made it back safely.
I have learned a lesson from your experience and will make an inspection of my bolts an annual (at the least) event.

 

[Max1]

Yeah, the coupler at the transmission. I have to admit, the only time I’ve ever checked my shaft bolts is when I did a seal change or pulled the shaft. Having to lay over the engine, it’s not that easy. After this incident and from what David added above, it goes on my list.

I'm going to do the same

Geez! Glad the Dude’s OK.

Reminds me to get our couplers checked out. The traditional coupler bolts have never been a problem, but some PO added a bolt on each coupler that goes transversely through the collar and the shaft. I occasionally find them sheared off and laying in the bilge. I replace them but, even with Grade 8s, they shear over time.

Folks, I strongly suspect one of the root causes of shearing of the shaft bolts would be misalignment of the engine to the prop shaft.

Still in my steep learning curve, I have downloaded and am still reading the Lehman owners manual and shop manual.

One of the items in the annual checklist is to check the engine alignment.
First time i read it, it was "what is that?"
But after I also read up on packing-gland stuffing, I opened mine up to check it and removed the old packing. The inner rings of the packing were OLD and hard as a rock. So good thing #1

Good thing #2: Then the next thing I noticed was now that the packing was out, I could not help but notice that the two mating parts on the packing gland- (not sure of the names, but the packing cylinder and the insert that is rammed into it) were out of alignment if I fit them together without the packing material. Not much, but rather than being perfectly in-line so that I get 1/4" clearance at top and bottom between the mating parts- perfect alignment for the 1/4" packing seals to fit in the gland, I was getting 1/8" clearance at the top and 3/8" clearance at the bottom. At that point I realised "this is what the Lehman manual must mean when they say to check the engine alignment"

I now realise that any misalignment would be transmitted to the prop shaft bolts that mate the engine to the prop-shaft. This misalignment would apply alternating compression and tension forces on the bolt leading to fatigue failure of the bolts as are being mentioned in this thread (same way a coat-hangar would break if you flexed it back and forth continually)
So check your alignment at your packing gland to make sure you are not fatigue- stressing your prop-shaft bolts.

 

[Bmarler]

Could be worse, Bill. They could have left the bolts off entirely, like a PO (or whoever he hired) did on my boat. As we were preparing to have damper plates replaced a few years ago, we noticed the Twin Disc on the starboard side budging ever so slightly whenever it was shifted in or out of gear. Upon disassembly, it turned out that FIVE (!) of the seven bolts supposed to be holding the tranny to the adapter plate were missing. These were not visible from the outside, so it was not possible to know they were AWOL without removing the Twin Disc. Nothing laying in the bell housing; they were simply never installed. Evidently, the weight and torque were being shouldered by some combination of the splined shaft, the prop shaft, some guide pins and the two bolts.

Glad you made it back safely.

good to know all you need is two right?
attention to detail is one thing, but forgetting to do the main thing is something else.

 

[Max1]

Or, it could be that I’m just a general dumbass.

Here is the last remaining bolt that was trying to hold the thing together. If you look closely the threads are smashed in the middle.


I had the transmission replaced on this boat a few years ago and I think they reused the same bolts, so I’m assuming this is the OEM bolt. Hard to see in the photo but this is a 10.9 grade bolt.

These bolts have an inherent weakness as OC Diver states below

Don't know if you can find them, but I prefer bolts where there is smooth shank in both flanges instead of thread.

Ted

These are much better bolts than the fully threaded bolts. These are called "Shoulder Bolts" and can be purchased with the shoulder at any length (generally).

Measure the thickness of the two mating parts and order shoulder bolts with the shoulder lengths equal to the sum of the two thicknesses minus 3/16" or the nearest size shorter shoulder. Don't forget to add the thickness of the washers and lock-washers if you plan use them

 

[KnotYet]

These bolts have an inherent weakness as OC Diver states below

These are much better bolts than the fully threaded bolts. These are called "Shoulder Bolts" and can be purchased with the shoulder at any length (generally).

Measure the thickness of the two mating parts and order shoulder bolts with the shoulder lengths equal to the sum of the two thicknesses minus 3/16" or the nearest size shorter shoulder. Don't forget to add the thickness of the washers and lock-washers if you plan use them

A shoulder bolt has a shaft that is larger in diameter than the thread size.
The bolt you pictured is usually called a partially threaded bolt as opposed to
cardude's fully threaded ones.
I grabbed this attachment from the McMaster-Carr site as an example of a shoulder bolt/screw.

 

[Max1]

A shoulder bolt has a shaft that is larger in diameter than the thread size.
The bolt you pictured is usually called a partially threaded bolt as opposed to
cardude's fully threaded ones.
I grabbed this attachment from the McMaster-Carr site as an example of a shoulder bolt/screw.

Thank you. I wanted to correct my post but the edit feature seems to have disappeared