Sheared Propeller Shaft

[kevbo5566]

I'm not sure how it happened, but after losing propulsion and assuming it was a transmission issue, it turns out my propeller shaft sheared in half directly in front of the strut. I haven't hit anything in over a year, so perhaps a small nick in the shaft eventually led to a stress fracture.

In any event, any suggestions on where to buy a new propeller shaft from? I've only ever bought parts online from skidim.com, but it doesn't look like they sell them.

I've got to replace the strut as well, which was bent when the shaft sheared. Hopefully, by getting a new strut and there shouldn't be any alignment issues. Any tips/tricks for this repair?

[docdrs]

Aquamarine of anderson indiana. Ron Hasting is the owner , im sure he could hook you up

[CornRickey]

Skidim. com. Great people. Something else...... Claim it on your insurance as a prop strike. Give them a quote with labor do it yourself and pocket some had money or upgrade your shaft seal. . With strut your probable looking @ 1500 in parts.

[Salty87]

struts can be straightened if not mangled too bad. is there a prop shop near you? shipping something like a strut will be costly.

nettles marine in austin is a fantastic shop. they'll ship stuff but...

[CJD]

Interesting that the strut is bent. I bet you did hit something, as a simple shaft failure shouldn't have any affect on the strut. Even if the prop moved back and contacted the rudder, the strut should be strong enough to take it.

[DKJBama92Mariah]

Odds are the last time you hit something, you bent the strut. Bending the strut will cause the shaft to be out of alignment, eventually causing it to snap.

Skidim has struts http://www.skidim.com/products.asp?dept=1124
As well as shafts http://www.skidim.com/products.asp?dept=1160

[kevbo5566]

I don't know what happened, but it didn't sound or feel like I hit anything. Perhaps the torque released during the failure of the shaft bent it over, but as the picture shows, it's certainly bent.

15847

[DKJBama92Mariah]

Sorry, I didn't explain my post well enough. You could have hit something and bent the strut a long time ago. The bend puts the shaft out of alignment which would cause this type of shaft failure when run long term. Don't feel bad, run an inboard long enough, and it happens to everybody. Here's a pic of the last one I bent.
http://img.photobucket.com/albums/v55/dkjpika/Boat/BentStrutPic-1.jpg

You can't just bolt the strut up and stick the shaft in, the bolt holes in the hull have enough wiggle room for the strut to be misaligned. I wrote a post years ago on strut replacement and making sure it's lined up. Let me see if I can find it.

[loopmaster]

My shaft has failed twice from not perfect alignment on it. So it does not take much misalignment to do this. My prop looked perfect, but when I measured, I was off slightly on the strut and that caused the second failure.

[DKJBama92Mariah]

Here's the post, almost 10 years ago. https://forum.supraboats.com/showthread.php?1023-prop-engine-alignment-questions&p=3747#post3747

Once you get the old strut off (let us know if you need help on that one, it's a challenge in and of itself). For purposes of alignment go ahead and bolt the coupler to the transmission output flange without the shaft installed in it. Apply your liberal coat of 3M 5200 sealant to the mounting flat of the new strut and loosely bolt it into the boat. Now, with the strut still loosely attached, insert the shaft through the strut, through the shaft log/stuffing box and into the tapered hole on the coupler. You can now tighten the nuts holding the strut on and your alignment should be pretty close. Once you have the strut secure, you can the remove the coupler from the transmission and properly fit it to the shaft.

Note: this will get your alignment pretty darn close, but I would still double check it before reattaching the coupler to the transmission.

[thepadokc]

Im assuming since i just bought a supra i need to crawl underneath and inspect all this and make sure mine isn't bent and going to cause this same issue?

Any other parts i should inspect while under it... can you tell from the outside how good the seals are?

[kevbo5566]

How does the thrust bearing/drive flange connect to the forward end of the propeller shaft?

The mechanic we're using has said that he's going to need to remove the engine and transmission to get the shaft out because he can't this piece off the end of the shaft? Is it typically necessary to remove the engine and transmission for a shaft replacement?

[wotan2525]

I'd pick up your boat TODAY! This guys a moron and shouldn't be trusted. The engine DEFINITELY does not need to be removed.

The drive flange will have 4 nuts around the outside, there is also a nut on the very end (inside of the flange.) Remove all of the outside nuts, slide shaft back as far as you can. Wedge a 2x4 against the prop to keep it from spinning. Then remove the interior nut (some people have had to cut down a full-size socket to fit it in with enough clearance. Be creative on how you're going to get to this nut -- it all depends on how far back you can get the prop shaft.) With this bolt removed the shaft may still be stuck on the coupler flange. You can put the right sized socket on bare shaft and then retighten the 4 outside nuts back against the transmission coupler. This will press the shaft out of the coupler.



http://i.imgur.com/ulGMTwy.jpg

[DKJBama92Mariah]

I'd pick up your boat TODAY! This guys a moron and shouldn't be trusted. The engine DEFINITELY does not need to be removed.

The drive flange will have 4 nuts around the outside, there is also a nut on the very end (inside of the flange.) Remove all of the outside nuts, slide shaft back as far as you can. Wedge a 2x4 against the prop to keep it from spinning. Then remove the interior nut (some people have had to cut down a full-size socket to fit it in with enough clearance. Be creative on how you're going to get to this nut -- it all depends on how far back you can get the prop shaft.) With this bolt removed the shaft may still be stuck on the coupler flange. You can put the right sized socket on bare shaft and then retighten the 4 outside nuts back against the transmission coupler. This will press the shaft out of the coupler.



http://i.imgur.com/ulGMTwy.jpg

Absolutely agreed 100%. This is how I take mine apart. There is absolutely no reason to pull the motor. I wouldn't let that mechanic touch my boat. If he can't get the terminology right and cant get the coupler off the shaft, then he has no business working on an inboard. I run into a lot of these guys. They work mostly on sterndrives and then just wing it when it comes to inboard work. I can't find anyone around here I trust, so I do it myself and know it's done right.

[Salty87]

It's possible for the coupler (drive flange) to be extremely hard to get off. Nettles Prop Shop (very inboard/drive shaft savvy) had to use their hydraulic press to separate mine once. JT said there was no chance I was going to get them apart.

Otherwise, I agree with the above. Unless you're at an inboard specialist you're likely dealing with an i/o mechanic who's a hack on inboards.

[CJD]

Just to add...the manual says to check the shaft alignment annually. If you hit something and bend the strut, shaft, or damage the hull...it is blatantly obvious when you do an alignment check. So it would also be a good idea to check alignment if you even suspect damage. I know from my earliest questions when I bought our boat that the majority of owners never check prop shaft alignment...until the shaft breaks!

[kevbo5566]

I should have stated it, but the shaft is shreared off, so it's not possible to jam the prop with a 2x4 (since it's not attached anymore) to prevent the shaft from spinning. I was thinking maybe he could use a pipe clamp or two around the shaft outside the hull connected to a 2x4. Any thoughts?

[Jetlink]

You're just trying to get the coupler off the old shaft so you can remove it and replace it with a shaft that is intact? Unbolt the coupler, loosen all the strut fittings and back the coupler off the transmission until you can fit the socket inside the coupler. Loosen that nut and then with just the socket in the coupler, thread the bolts between the coupler and the transmission output shaft and tighten until the coupler pops free from the shaft. That should do it if that is what you are trying to accomplish here.

[docdrs]

A pipe wrench wedged against the hull will stop if from rotating if necessary

[jzelt]

I would do the above steps with socket and coupler, tighten it, hit the shaft a few times with a hammer, rotate it, hit it again and maybe the vibrations will loosen it, try to tighten it some more.

[Salty87]

Some beers, blades and a sawzall. Of course, I've never worked on a vdrive and have no idea what the access is like.

[wotan2525]

Some beers, blades and a sawzall. Of course, I've never worked on a vdrive and have no idea what the access is like.

This is exactly what I was going to say. Sawzall should make quick work of this if you don't need to save the shaft.

[docdrs]

You might be able to get a puller on it once the set screw and nut are removed. Heat on the coupler can help free them with a puller as well . If there was no hull damage it is possible that full power turns can bend rudder posts and cause shaft fatigue ( ha ha) and future failure

[Jetlink]

If there was no hull damage it is possible that full power turns can bend rudder posts and cause shaft fatigue ( ha ha) and future failure

This anti-power turn PSA brought to you by Cialis for daily use and docdrs.