Prop shaft broke...replacement issues?

searaycruisn

searaycruisn

New Member
Nov 10, 2006
242
Old Saybrook, CT
Boat Info
2000 380 Sundancer
Engines
CAT 3126
We were about 45 minutes into our weekend trip on Friday, when all of the sudden, lack of power, and a thud! I do not believe I hit anything solid, since I was in 100FT of water, but I probably hit a submerged floating object. I powered down and got in the water and sure enough, the shaft had sheared off just behind the strut. Propeller was gone. There was fiberglass damage in the cavity presumably where the propeller hit the hull on the way down.

In the spring, I removed the propellers and had them rebalanced. I can't help but think that all that banging on the propeller puller with a sledge hammer had something to do with weakening the shaft....

Anyways, I called the local propeller shop and they said they can make a shaft in three to five days. All they need are the "measurements". I asked him why he could not make the shaft from factory specs (which I assumed are available somewhere), and he said that "each boat is different, based on where the motor mounts are installed".

Does this make sense? The yard committed to hauling the boat on Monday and getting the "measurements" over to the prop shop "first thing", but I am not too confident that will happen based on prior commitments the yard has made, and not kept. I hoped there were factor specs the shop could use to start making the shaft right away.

Also, any other issues, questions etc. that I should speak to the yard or the propeller shop about? Anyone know what this might cost? I have a $2,000 insurance deductible....
 
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I'd think a quick call to SR CS could net you the answer to the shaft dimensions. I'd recommend this because you are missing part of the shaft. If all of the shaft were present, measuring it would be a snap.
Look at the condition of the cutlas bearing while it's out. An off handed guess at the price not including the yard fees would be about $1000.
 
This is from my other thread, but I thought I would copy it here since it gets right to the point:

Here's the repair and cost breakdown:

I had the broken shaft, coupler and starboard prop removed and sent to Admiral C&B Prop in Tampa. Bob, the owner, took great care of me. He found that I did not have Federal wheels, but Hall and Stavert Hy Torq. Admiral did the following:

Provided a new 73.46" 1 1/2" AQ22 shaft and machined it to my coupler: $899
Provided a new 20x25 Hy Torq Nibral Prop and hardware: $1220
Reconditioned, balanced, scanned, etc. the old prop and new prop to match: $350

MarineMax did a "dye" check of my starboard shaft to determine if there were any stress cracks or signs of fatigue- none were found. They also checked the cutlass bearings, re-installed the shaft, and re-aligned everything. The glass tech repaired the gouge in the tunnel caused by the wheel leaving the shaft. Since MarineMax had just done a bottom job, they reapplied the epoxi coat on the shafts and wheels and repainted the entire area with Cukote. Total labor: $450 for the shaft, coupler, alignment, etc. and $175 for the glass and paint work- all of which I thought was very fair.

So it was a somewhat expensive repair to have happen just two week into ownership, but now I feel good that it is done and over, hopefully not to happen again!
 
Yes, Aquamet 22, which is supposed to be stronger than Aquamet 19. The shaft had to be machined to fit the coupler, which also added cost.
 
Interesting.....same boat....same failure.

Mine also happened at 2400RPM, cruising in 100FT of water...so there was not recovering the propeller! However, I just had my props reconditioned in May, so there should be no problem replacing the prop, and matching it to the port side prop, since they have all the specs.

Still wondering though, does the shop really need "measurements" from a broken shaft??

Or do they get them from SR?

The guy at the shop started trying to explain to me how to measure the shaft, and I stopped him and told him that I am sure the yard would give him the information he needs, since I was not going to attempt the repair myself.
 
AQUAMET 22 is a high-alloy austenitic stainless steel that provides superior corrosion resistance along with excellent toughness and high strength. It has higher strength than AQUAMET 17 in diameters of ¾" through 1¼", and equivalent strength in diameters up to 2". Due to its high alloy content, AQUAMET 22 resists pitting and crevice corrosion and is ideal for pleasure boats which are operated infrequently, spending much of their time tied up at docks. (AQUAMET 22 H.S., a higher strength version, is available in 2½" to 6" diameters.)

You say you removed the props; did you replace them as well?
Proper seating of the keyway is critical to avoid unbalanced stress on the shaft. If the keyway is not properly seated, it can often be the cause of the shaft snapping just behind the strut. I'd have the shop examine the old shaft to see if they can make a determination, but it might take a metallurgist for a definitive cause.
 
Yes, I did reinstall the props. I am very confident that the propeller was seated properly on the shaft and the key. I do not think that was a contributing factor.
 
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I gave my broken shaft the the machine shop and they replaced it. I don't know where they got thet exact measurements.

My machine shop told me that 1 1/2" shafts are about the minimum size for a boat of our size with the torque of diesels. He told me that he sees bigger diameter shafts from other boat manufacturers in similiar weight/ diesel hp set ups. I also have heard snapped shaft causes can be metal fatigue, shafts could have slight misalignments causing whips, and as mentioned, the keyway not set properly.

It is an unfortnuate problem, but it can be fixed!
 
I have had had to replace both my shafts about 1 year apart on my 1989 44 footer. I called up Sea Ray and they looked up the lenght for me. They have all the boats parts on their web site also. They were very helpfull on the phone. They even had to go to their archives building and pull out the info because of the age of the boat. If you can get the lenght most people who do shafts know the taper for the props and how to machine the coupling end. I had them made from aquamet 19. Seemed to work fine as I ran the boat another 600 or so hrs after they were replaced. My shafts were about 1320.00 ea. so it seems as though you are getting a good price. Good luck with it.
 
I would also check your alignment when you are finished as well as your cutlass bearings. They could be on their way out which in turn caused substantial runout and hence why the shaft broke.

Doug
 
Insurance might cover the repair. That's not normal wear and tear.

Best regards,
Frank
 
Eric:
After buying my boat- at the first haul for a bottom job- the mechanic called me to come out and take a look at the unevenly worn bearing. I was pizzed that my surveyor missed it (and it was obvious enough that I should have caught it myself). The port bearing was so worn on one side that the rubber insert was gone- and the shaft had gotten scored. Had it continued unnoticed I'm sure the shaft would have eventually snapped.

In my case, when we took a closer look we noticed that the strut was slightly bent. We pulled the strut and sent it out along with the shaft and coupler to be straightened. Shaft was too badly scored to be used and needed a new one, but the strut got straightened out and solved most of the problem. The alignment was still slightly off, so we shimmed the strut a tiny bit which got us within tolerance. So, didn't need to re-align the engine.
 
Just got a call from the propellar shop.

The shaft has been removed, and they are taking measurements to cut a new shaft. Propeller is on order and on its way. I did not speak with the yard mechanic, so I don't know if the allignment issue is at the engine, or the strut.

I will report back, once I get all the facts.

Called my insurance agent yesterday to report the loss. Still waiting for a call from the adjuster. By the time I hear from him, I hope the boat will be back in the water!
 
way back when, with this boat...
boat4sale.jpg


i was running back to the marina and suddenly heard a strange grating sound coming from the drive. had a mechanic look at it and he said "you'd better call your insurance company, and when you do, tell them you 'hit something.'" good advice. bearings or gears or something in the top of the drive were shot. needed a complete rebuild, which allstate paid for no questions asked. at that time (1999) it cost about $1100 for an alpha one.
 
Same thing happened to a new 34DA that was cruising with us last month. 60 ft of water, nothing to hit, two clunks and the shaft shears off like it was cut with an electric hacksaw just aft of the strut. The first clunk was the break the second was the prop hitting the tunnel. The owner was stuck in the Bahamas for a week waiting for parts, haul out and repair.
 
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