1971 36c shaft size

[hatterass]

I am om my second shaft coupling in the last several years. I think the shaft needs to be replaced as it is hogging out the keyway and coupling. Does anyone know how long the shaft is or where I could get one? I know the shaft is 1.5 in in diameter. Any help would be great!
Thanks in advance.

 

[saltshaker]

You can call SAMs with your hull ID and they will tell you what they were when they left the factory. If they were changed at some point they may not be the same. Safest way is to pull the shaft and have it measured. As for a source, start with your local prop shops and see what they offer.

 

[hatterass]

Good point. I was trying not to have the boat pulled several times. I am running a charter boat service and can't have it out that long. Unfortunately I may have no choice.

 

[Boatsb]

What type of a coupling are you using ?

You may want to replace both at once with a version that has a taper and nut or pinch bolts that can be tightened.

 

[saltshaker]

If you have the original power and both are positioned similarly, they probably are the original length shafts. If they are double tapered shafts, you'll want to send the coupling out when the shafts are made to get a custom fit. Find out what they were, line up a shop to do the work and then you can pull the shafts and couplings when they're ready to do the job. A couple of inches shouldn't make much of a difference in price. Have them cut the shafts after they confirm the size of the ones you are replacing. Make sure all the clearances are good first. Now would be a good time to make any adjustments. I had a previous boat that had very little space between the strut end and the prop hub. An extra inch would have made a big difference when pulling the props.

 

[Fanfare]

A little extra space also lets you install line cutters such as Spurs.

 

[saltshaker]

A little extra space also lets you install line cutters such as Spurs.

Which is what I wanted. I ended up adding drive savers to get the extra space I needed.

 

[Avenger]

You can call SAMs with your hull ID and they will tell you what they were when they left the factory. If they were changed at some point they may not be the same. Safest way is to pull the shaft and have it measured. As for a source, start with your local prop shops and see what they offer.

Yeah, I don't think Hatteras built them with Perkins. Better to pull and measure to be sure. It's an expensive oops if you can't cut them longer.

 

[jim rosenthal]

The original shaft spec in these boats is for Aquamet 22, I think at least 80K PSI tensile strength. The wheel end is tapered; the coupling end is not. I think they are about 108" but that is only a guess. It does sound like the shaft at least needs to be straightened and the boat realigned; also are the cutlass bearings in good shape? If they are worn, the shaft may move laterally too much as it rotates.

We just had the shafts out of my identical boat, and straightened; we also fitted new cutlass bearings and realigned both sides. An alignment check in the water is in the near future.

 

[saltshaker]

Did I miss the Perkins reference?

 

[hatterass]

Yes I have Perkins. Tapered shaft at prop and straight at coupling. 1.5" diameter. I believe they are original. the coupling is not split but has a keyway and set screws. The keyway and he coupling are getting rounded out. the cutlass brings a just did a few years ago and were good when I pulled the boat last. I think it's best to get the new shaft and coupling and the same time to make sure they work together. Then get it aligned in the water. I just had the props tuned about 5 mo. ago as well.
Thanks for the response

 

[saltshaker]

SAMS will tell you but I don't think Perkins were a factory option. Most Hatts I've seen have a double taper. Not sure if that's the case for the 36C but if so that's more indication that your shafts aren't original.

 

[jim rosenthal]

Diesel option would have been 3160 Cats, there are still a few boats running around with them, they were very durable. I don't think any of these were built with Perkins or DDs, not that I am aware of.
Perkins, not a bad choice for the time, though, as they are lighter than Cats and probably make nearly as much hp.

 

[dsharp]

There is no reason for the shaft to be causing any wear inside the coupling unless the fit is too loose. To fix it correctly buy a "blank" coupling and take it to a machine shop with the shaft. Take it to someone that does boat work. Tell them to bore the coupling where it takes 4 or 5 hits with a hammer to seat the shaft. Obviously put a block of wood on the coupling. Then tell them to face the coupling while it's on the shaft. Dimple the shaft for the set screws. If the end of the shaft is mangled from flopping in the coupling it won't hurt it to take a light cut to smooth it. The 1 1/2 inch shafts didn't have tapered couplings on the engine end. If you get a shaft made make sure you and the machine shop are on the same page about length. Some want overall length, some want to the end of the taper, etc. Also tell them if you want double nuts or single castle nut.

 

[Avenger]

Did I miss the Perkins reference?

No. It's local knowledge. But being it's repowered I wouldn't take it on faith that they used the original shaft length. Especially with an inline 6.