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View Full Version : Snapped shaft on 84 s&s


Jayc
07-26-2009, 05:14 PM
The guy who bought my old s&s called me over yesterday when he said he had no drive. I had a looked and found the shaft had snapped between the coupler and the log.

I've only ever seen one shaft snap and that was after major impact. The guy swears he didn't hear and big bang it just stopped moving. Prop has some damage but could be from previous impacts or from where it slipped back and hit the rudder.

I pulled the coupler today and am waiting on a prop puller to get the rest of the shaft out. I looked in my garage as I new I had 2 shafts which my father had gave me. He had owned many s&s, rainbow and late pro comps so I had spares from them but the shaft I found whilst being the right length and dia are not tapered both ends. Any idea if I can get them to work with my coupler?

http://img268.imageshack.us/img268/4297/26072009016.jpg

http://img198.imageshack.us/img198/9691/26072009017.jpg

http://img198.imageshack.us/img198/2902/26072009015.jpg

Jerseydave
07-26-2009, 05:29 PM
25 year old propshaft, no surprise really. Plus in your pic you have alot of rust on that flange, which should be replaced as well. Maybe the shaft had some corrosion as well?

I'm no expert, but I would not mess around trying to get your spare shaft to work. Keep in mind how many rpm's that shaft turns, I'd get a new shaft, flange and have the prop reconditioned. Just my $.02

CameronCarey
07-26-2009, 05:30 PM
Nice Pics Thanks for sharing them.
From a strength analysts perspective (what i do when I am not working on my boat) that looks like a faitgue crack which grew to failure over time.

It probably started at the keyway......... it would have likely sheared more unevenly from the material yeilding and stretching with the sudden impact load if he had hit something.

Supposedly this happend on my boat too.........before i bought it. The cause was soft stringers which allowed the boat and shaft to flex..

Jayc
07-26-2009, 05:48 PM
No visable corrosion on the shaft but it has been used and left moored for the past 25 years in saltwater so that will explain the corrosion on the coupler.

Problem is a new shaft and coupler here in the UK is likely to cost about 25% of the boats value! Still, glad it's no longer my boat so not my money but was hoping to sell one of the shafts I had as tey are no use to me anymore.

CameronCarey
07-26-2009, 05:55 PM
www.skidim.com has alot of neat options for replacement shafts...........no idea about any import tarrifs though........I am sure they ship international......if not..........that shaft and coupler would be pretty simple for a machine shop to create with even the crudist of lathes.....it may be one off those times when making it custom is cheaper than purchasing it

Cloaked
07-26-2009, 07:25 PM
www.skidim.com (http://www.skidim.com) has alot of neat options for replacement shafts...........no idea about any import tarrifs though........I am sure they ship international......if not..........that shaft and coupler would be pretty simple for a machine shop to create with even the crudist of lathes.....it may be one off those times when making it custom is cheaper than purchasing it
Agreed. I'd get an e-mail exchange started with someone at Skidim and they will guide you to the right part if you decide to purchase new. As well, they will ship accordingly.

Very good people to deal with..

As stated, cyclic failure appears to be the culprit. with a stress point in the keyway. Odd but certainly not out of the question.

justinglow
07-26-2009, 07:27 PM
On one of my older boats I had to replace the shaft. I ordered a new A.R.E one from skidim and it worked out perfect. Comes with a new coupler. Measure the old one and order a new one from them. It's worth it.

TMCNo1
07-26-2009, 08:09 PM
You can also check out these sites, http://www.elberts.com/system.htm
and http://www.ojprops.com/services

Jayc
07-27-2009, 11:39 AM
Will likely get a new shaft made up locally as shipping from the states would not be practicle. Cheers for the advice though guys.

Bouyhead
07-29-2009, 10:25 AM
Jayc, don't forget to check your alignment between tranny flange and the shaft flange, and check stingers and engine mounts. Iv'e seen shafts break on the old boats do to bad stringers/mounts/and associated hardware. if any of these are bad the engine can lift up under hard acceleration causing the shaft to break.

CameronCarey
07-29-2009, 01:04 PM
Jayc, don't forget to check your alignment between tranny flange and the shaft flange, and check stingers and engine mounts. Iv'e seen shafts break on the old boats do to bad stringers/mounts/and associated hardware. if any of these are bad the engine can lift up under hard acceleration causing the shaft to break.

This is Obvious but great input!