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Beneteau 361
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Discussion Starter · #1 · (Edited)
I am trying to source a new shaft/transmission coupling (as a result of cutting off the old one). Beneteau can sell one for $250 which is a bit steep. I checked Buck Algonquin catalog and they don't seem to make this size. Is there any other options? Some other manufacturers?

 

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I am trying to source a new shaft/transmission coupling (as a result of cutting off the old one). Beneteau can sell one for $250 which is a bit steep. I checked Buck Algonquin catalog and they don't seem to make this size. Is there any other options? Some other manufacturers?

Not a Beneteau original part, if you knew the dimensions and the make/model of gear box it would be easier to find a match.
 

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One of None
Hunter 34
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uh... shaft size? Guessing, it's metric?
 

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Vetus makes some nice flexible couplings, I have the older version of this type, and have been happy with it, still going strong after 15+ years... And they come in metric sizes...

Flexible couplings - Stern gear systems

Probably gonna run more than $250 these days, however... I'm guessing you're gonna be hard-pressed to find a decent coupling for much less than that, anyway...

And, if you go with something like the Vetus, you probably won't have to destroy it by cutting it off, next time...

:)
 

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Old as Dirt!
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You might try TransAtlantic Diesel . Next time, if there is one, it might be wise to query the Board about freeing a shaft from a coupling without destroying either. It is fairly easily done without pounding the crap out of the gear or destroying expensive equipment.
 

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Beneteau 361
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Discussion Starter · #8 ·
Vetus looks great but would only work with straight shaft. Mine is tapered.

I will check out TransAtlantic Diesel, thanks.

I would be very interested to learn how to easily get a coupling off next time! The methods I've tried are:
- soaking in PB blaster for ~ 1 month
- custom steel pressing plate + 4 bolts
- 6' three-jaw gear puller
- heating with oxy torch

No I did not forget to remove the nut! :)
 

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One of None
Hunter 34
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could a machine shop make one for that cost or there about?
 

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I think you can get one from Buck with no shaft hole at all. Having a shop drill one of those to match your shaft should be cheaper than having them build it from scratch. Or you could get one with smallest hole they have and have the shop open it up. Buck couplers can be had for about $60 plus shipping online.
 

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Beneteau 361
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Discussion Starter · #14 ·
I would only trust a machine shop if I could bring the shaft and have it fit and faced. Unfortunately this would require removing the rudder, which I am not planning to do. So it looks like the best option will be OE part.
 

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Old as Dirt!
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That's right. Both ends are tapered. Seems to be a standard thing with Beneteau.

Ah... Sorry old son, but that's definitely not a Beneteau practice nor a practice by any other builder /manufacturer. What you have there is the outboard end of a shaft. I suspect that at some time in the past a former owner decided to swap out the prop and discovered that the stock taper on the 25mm shaft didn't match up with the taper in the new prop. Rather than swapping out the prop, he/she just had the inboard end of the prop machined to the prop's taper and threaded for the new prop note (presumably less costly than buying a new shaft or swapping out the replacement prop). The reason you had such difficulty extracting the shaft from the coupling was, undoubtedly, due to a "force fit" (I'm sure that will have done wonders for the bearings in the transmission--expect/look for problems there n the future- and the motor mounts). Shafts are, normally, held into couplings with a snug fit and a couple of set screws. That's so because 99% of the time, the prop is pushing the shaft into the coupling and only occasionally trying to pull itself out (with far less thrus/"pull"). If you want to do that "fix" properly, get yourself a new Aquamet 25 mm shaft (in your little boat likely less than $500 USD), have the outboard end milled and threaded to match your prop, and pitch that old shaft in the trash.

In future, to "extract" a shaft from a coupling, loosen the mount and insert a short chunk of 3/4" pipe between the end of the shaft and the boss of the coupling mount on the transmission. Hold it in place with your finger-tips or a pare of forceps while you, or a helper gently tighten the coupler mounting bolts (in a star pattern) and, with in a few tightening cycles, that shaft will slide out without any brain damage.

Use your head instead of your bicep's, you'll do better.
 

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Ah... Sorry old son, but that's definitely not a Beneteau practice nor a practice by any other builder /manufacturer. What you have there is the outboard end of a shaft. I suspect that at some time in the past a former owner decided to swap out the prop and discovered that the stock taper on the 25mm shaft didn't match up with the taper in the new prop. Rather than swapping out the prop, he/she just had the inboard end of the prop machined to the prop's taper and threaded for the new prop note (presumably less costly than buying a new shaft or swapping out the replacement prop). The reason you had such difficulty extracting the shaft from the coupling was, undoubtedly, due to a "force fit" (I'm sure that will have done wonders for the bearings in the transmission--expect/look for problems there n the future- and the motor mounts). Shafts are, normally, held into couplings with a snug fit and a couple of set screws. That's so because 99% of the time, the prop is pushing the shaft into the coupling and only occasionally trying to pull itself out (with far less thrus/"pull"). If you want to do that "fix" properly, get yourself a new Aquamet 25 mm shaft (in your little boat likely less than $500 USD), have the outboard end milled and threaded to match your prop, and pitch that old shaft in the trash.

In future, to "extract" a shaft from a coupling, loosen the mount and insert a short chunk of 3/4" pipe between the end of the shaft and the boss of the coupling mount on the transmission. Hold it in place with your finger-tips or a pare of forceps while you, or a helper gently tighten the coupler mounting bolts (in a star pattern) and, with in a few tightening cycles, that shaft will slide out without any brain damage.

Use your head instead of your bicep's, you'll do better.
Wow, and said with such authority, too bad it is wrong...;);):D

This is done quite widely and lots of builders use a double taper shaft. About half the shafts my local shop builds are double taper.. All the later Sabre's and all the Back Cove and Sabre Express boats are double taper. Most every commercial boat I work on is double taper. Double taper is the top-quality method, straight couplings are a cost saver. I am honestly surprised Beneteau used a double taper as it is a more costly shaft to produce...

This one was for one of the last Sabre sailboats ever built..


And here's what they look like when you do a cut away.


I hate to break it to the OP but he's going to need a fit & face if he wants a smooth drive-line....... A double taper does not remove the need for a proper fitting and facing..
 

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Beneteau 361
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Discussion Starter · #18 ·
Ah... Sorry old son, but that's definitely not a Beneteau practice nor a practice by any other builder /manufacturer. What you have there is the outboard end of a shaft.
Sorry pal, your theory is fascinating but it makes no sense. Both ends of the shaft are identical and tapered. Outboard end fits my Flexofold as well as original Beneteau prop perfectly. Inboard end fits original B coupling. The tapered bore of the coupling is the same as prop's. There are no set screws on the coupling and it is held in place by lock nut.

In future, to "extract" a shaft from a coupling, loosen the mount and insert a short chunk of 3/4" pipe between the end of the shaft and the boss of the coupling mount on the transmission. Hold it in place with your finger-tips or a pare of forceps while you, or a helper gently tighten the coupler mounting bolts (in a star pattern) and, with in a few tightening cycles, that shaft will slide out without any brain damage.

Use your head instead of your bicep's, you'll do better.
Anyone keen on using their head will realize this is a good way to warp the tranny flange and it takes 15 minutes to make a pressing plate from a chunk of steel with the same bolt pattern.
Puller is even better but you need more room.

 

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Beneteau 361
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Discussion Starter · #19 ·
I hate to break it to the OP but he's going to need a fit & face if he wants a smooth drive-line....... A double taper does not remove the need for a proper fitting and facing..
I would love to do that but it would require dropping the rudder. In fact I am wondering if this is done on new boats at the factory? Probably not, at least not at Beneteau.
 

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I would love to do that but it would require dropping the rudder. In fact I am wondering if this is done on new boats at the factory? Probably not, at least not at Beneteau.
The shafts and couplings are usually milled and fitted and faced before they go on the boat. They remain as a pair until installed. It would not be worth it to Beneteau to not fit and face them. One warranty claim would wipe that savings out quickly... First they are fit (lap fit) then faced for true. You could lap fit yours but the face may still not be true, usually they are not....

If you can press out the cutlass bearing the shaft will almost always clear a rudder... I remove shafts regularly that won't clear with the cutlass and when removed clear just fine...
 
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