DAVIDO
Well-Known Member
Second that have used these fenner taper locks in various heavy industrial applications and they are superb.
shafted
- Thread starter siencyn
- Start date
bendyone
Well-Known Member
The standard Yanmar gearbox coupling relies on just a clamp effect (no keyway) IGM10
john_morris_uk
Well-Known Member
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I am sorry to report that it is a design fault. I either have to drop the rudder or remove the engine on my boat to get the shaft out!
[/ QUOTE ]How do you make it out to be a design fault? What do you see as being the problem with such a design?
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"Artificial intelligence is no match for natural stupidity"
sailroom <span style="color:red">The place to auction your previously loved boatie bits</span>
[/ QUOTE ]Perhaps my reply was ambiguous? I believe that its your boat that is designed correctly. My Westerly doesn't allow me to remove the shaft without either removing the engine or the rudder first. I believe that it is a design/build fault. Skewing the shaft (as on your boat I believe) allows the shaft to be withdrawn past the rudder/skeg and doesn't alter the performance under power in any measurable way. I just wish my boat had been made like that.
[ QUOTE ]
I am sorry to report that it is a design fault. I either have to drop the rudder or remove the engine on my boat to get the shaft out!
[/ QUOTE ]How do you make it out to be a design fault? What do you see as being the problem with such a design?
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sailroom <span style="color:red">The place to auction your previously loved boatie bits</span>
[/ QUOTE ]Perhaps my reply was ambiguous? I believe that its your boat that is designed correctly. My Westerly doesn't allow me to remove the shaft without either removing the engine or the rudder first. I believe that it is a design/build fault. Skewing the shaft (as on your boat I believe) allows the shaft to be withdrawn past the rudder/skeg and doesn't alter the performance under power in any measurable way. I just wish my boat had been made like that.
jerryat
Well-Known Member
[ QUOTE ]
FWIW, The standard coupling used on Bukh engines is a similar clamp arrangement to those above and I do not recall ever hearing of anyone pulling the shaft out going astern. I have heard of owners having problems getting the shaft out of the coupling even with the clamp bolts removed!
[/ QUOTE ]
Hi Cliff,
That's not actually the case. Two of the four bolts that clamp the 'split' coupling onto the shaft are so aligned that they actually fit into two matching grooves cut into the shaft. So even if all the bolts were completely slackened off, the shaft cannot slide aft or forwards!
FWIW I don't like the idea of using an un-keyed coupling whatever the manufacturers claim. I think there should always be a 'fail-safe' system to prevent losing the shaft, with possbly fatal consequences.
FWIW, The standard coupling used on Bukh engines is a similar clamp arrangement to those above and I do not recall ever hearing of anyone pulling the shaft out going astern. I have heard of owners having problems getting the shaft out of the coupling even with the clamp bolts removed!
[/ QUOTE ]
Hi Cliff,
That's not actually the case. Two of the four bolts that clamp the 'split' coupling onto the shaft are so aligned that they actually fit into two matching grooves cut into the shaft. So even if all the bolts were completely slackened off, the shaft cannot slide aft or forwards!
FWIW I don't like the idea of using an un-keyed coupling whatever the manufacturers claim. I think there should always be a 'fail-safe' system to prevent losing the shaft, with possbly fatal consequences.
cliff
Well-Known Member
I was just thinking that myself when I re-read your post - could have been read either way.
I did not realise the shaft was slightly offset until I was changing the seals and had slid the shaft back as far as it would go to get the seal assenbly off the inboard end noticed the offset - first thought was a bent "P" bracket but found out the offset was by design.
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"Artificial intelligence is no match for natural stupidity"
sailroom <span style="color:red">The place to auction your previously loved boatie bits</span>
I did not realise the shaft was slightly offset until I was changing the seals and had slid the shaft back as far as it would go to get the seal assenbly off the inboard end noticed the offset - first thought was a bent "P" bracket but found out the offset was by design.
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sailroom <span style="color:red">The place to auction your previously loved boatie bits</span>
cliff
Well-Known Member
Sorry if I mislead you. Actually I was referring to the type where the bolts intersect the shaft (fit into matching grooves cut into the shaft). IIRC on my arrangement (DV24) all 4 bolts slide into matching grooves cut into the side of the shaft (two grooves on each side). I have never had the shaft move as the bolts always slide out easily which they would not do if the shaft had moved either axially or radially as such movement would "nip" at least one of the bolts. Anyway I agree it is a better solution even if not necessarily needed under normal circumstances - no harm in a little "belt and braces" /forums/images/graemlins/grin.gif
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"Artificial intelligence is no match for natural stupidity"
sailroom <span style="color:red">The place to auction your previously loved boatie bits</span>
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sailroom <span style="color:red">The place to auction your previously loved boatie bits</span>
jerryat
Well-Known Member
Hi Cliff,
Come to think of it, I'm sure you're correct and all four bolts engage with grooves in the shaft. Have to really wouldn't they otherwise the shaft would be unbalanced and vibrate horribly!! /forums/images/graemlins/frown.gif /forums/images/graemlins/smile.gif /forums/images/graemlins/smile.gif
Come to think of it, I'm sure you're correct and all four bolts engage with grooves in the shaft. Have to really wouldn't they otherwise the shaft would be unbalanced and vibrate horribly!! /forums/images/graemlins/frown.gif /forums/images/graemlins/smile.gif /forums/images/graemlins/smile.gif
pvb
Well-Known Member
Straightforward clamps are OK...
There isn't a problem using straightforward clamps without keyway or machined grooves on the shaft. The standard Volvo Penta shaft clamp (pic below) needs no machining of the shaft and has been fitted to thousands and thousands of boats.
There isn't a problem using straightforward clamps without keyway or machined grooves on the shaft. The standard Volvo Penta shaft clamp (pic below) needs no machining of the shaft and has been fitted to thousands and thousands of boats.
awol
Well-Known Member
I am ignorant of the rudder/sked configuration of a Countess 33 but if it is similar to the Contessa 32 with the propellor exiting through the skeg then removal of the bottom of the skeg to drop the rudder is no problem. The idea was frightening before I did it, but the reality was a relief - the only hitch was waiting for a warm enough day to glass the skeg back on!
stubate
Well-Known Member
cut the shaft in situ, take the bits out, take the bits to a good machine shop and they will cut keyways in the shaft. dont forget to measure good where you need to cut otherwise you may cut and still not have enough slide to get it out.
stu
stu
