broken bolts off the flexible coupling


phil.berghmans <no_reply@...>
 

Hello everybody,


I discovered a few weeks ago a broken (off) locknut under the engine ... i discovered it was one off the 4 locknut/bolts off the flexible coupling/ generator .

I tigthened the three remaining locknut bolts and continued sailing motoring in the bocas del toro area panama.

It was mostly motoring and no heavy seas i useally motor my MD22 L at 2400 revs and do more or less 5 to 5.5 knots depending on the seastate.

Yesterday i motored out off an anchoridge and noticed more fibrations and tougth i had something in the propeller... took a dive and checked it... nothing .I went in the engineroom and discovered two more bolts and lock nuts from the flexible coupling had broken off . i motored backslowly and i am  now in a safe anchoridge.

All my plans to go north are gone... 

Does anyone have any experiance with this problem? All the advice, suggestions  are wellcome


Chased murphy off the boat and hope he stays away.


Thank you in advance


Phil


Miles ahead


Santorin 1994 nr 101

 



Alan Leslie
 

Yes !...
I heard of a Maramu that had broken bolts.
The engineer that repaired it advised me to check the bolts....I did, and found they were a little loose.
I tightened them and now check them every month or so...and so far they are still tight.
I believe the problem is that they vibrate loose and after some hours of being driven in the loose state they break.
Also the way Amel assembled that coupling they are almost impossible to get out.
There are other older posts on the forum about this....and how to replace them.
Good luck
Alan 
Elyse SM437


phil.berghmans <no_reply@...>
 

thank you allen, could be wrigth what you say about checking them on a regular basis would prevent the problem, i will certainly do so in the future..
 thank you
phil


Craig Briggs
 

Hi Phil,
This is a common problem - see several old posts by searching Vetus Coupling.  

Basic issue is the bolts will not come out unless you slide the engine back 2 or 3 inches and remove the coupling from the shaft going into the C drive. Moving the engine takes about an hour or two and is not difficult to do: take the nuts off the unbroken coupling bolts,  remove the 4 engine mounting bolts then take the weight off the engine with line run through the mainsheet block on the mizzen from the engine lifting rings to a primary winch - belay that line forward with a snatch block so it doesn't load up against the engine room hatch cover. 

The next step is you've got to remove the Vetus coupling from the C drive shaft. This can be easy or nearly impossible.  I've done it on a couple of Santorins and actually broken a very beefy wheel puller - finally fabricated one of 1/2 inch plate steel and it worked. Got another one off with a hand sledge hammer and several different chisels and steel wedges and about 5 hours of frustration.

I'd say give it a try but if the coupling is really stuck, give up early and go to Plan B, which is to cut off the heads of the broken bolts with a hacksaw and get them out - then replace with threaded studs with nuts on both ends. Or just go with Plan B only.

By the way, Amel had welded a little angled rod onto the bolt heads that goes into the Vetus coupling and keeps the bolt from turning when you tighten the bolts - that nice but not needed as you can easily get an open end wrench (spanner) on both the bolt head and the nut.  Do use Nyloc nuts and do not overtighten the bolts which is likely the reason they failed in the first place as the Vetus Flex coupling is by definition going to flex.

Good luck with it,
Craig Briggs, 1992 SN#68 Sangaris


---In amelyachtowners@..., <no_reply@...> wrote :

Hello everybody,


I discovered a few weeks ago a broken (off) locknut under the engine ... i discovered it was one off the 4 locknut/bolts off the flexible coupling/ generator .

I tigthened the three remaining locknut bolts and continued sailing motoring in the bocas del toro area panama.

It was mostly motoring and no heavy seas i useally motor my MD22 L at 2400 revs and do more or less 5 to 5.5 knots depending on the seastate.

Yesterday i motored out off an anchoridge and noticed more fibrations and tougth i had something in the propeller... took a dive and checked it... nothing .I went in the engineoom and discovered two more bolts and lock nuts from the flexible coupling had broken off . i motored backslowly and i am  now in a safe anchoridge.

All my plans to go north are gone... 

Does anyone have any experiance with this problem? All the advice, suggestions  are wellcome


Chased murphy off the boat and hope he stays away.


Thank you in advance


Phil


Miles ahead


Santorin 1994 nr 101

 



jochen@...
 

Phil,
as far as I remember it is the same coupling on the Maramu (Vetus Flexcoupling model 6 35mm shaft (KO53)).
In case that's true I just wanted to let you know we have the coupling here as a spare - bought it last autumn to replace when we next time get on the hard. That did not happen so far, will only next winter and until then we are going to travel to the states and canada and can buy replacement. We don't have any bolts though... Let us know if you need.
Jochen and Traudl
Maramu #143 Blue Song


phil.berghmans <no_reply@...>
 

Hello Jochen,

Thank you for the offer.But the flexible coupling/generator is not broken only the bolts...

Thank you

Kind regards

phil

miles ahead


phil.berghmans <no_reply@...>
 

Hello craig,

Than you for your reply. I think i will try "plan B"

Kind regards

Phil



seafeverofcuan@...
 

Dear Phil,
             If the coupler bolts have sheared then it is certain that the rubber bushes inside the coupler will be destroyed and need replaced.
Regards,
Trevor Lusty
Seafever of Cuan
SM 425 Redline
Mexico
For Sale