Beneteau 331 vibration

[mrplastic]

Hi all

When motoring my Beneteau 331 today I am aware of a vibration. It's worse at 1500 - 2000rpm and smooths out at 3000rpm although its still present. The engine a 20hp Volvo runs very well and Im guessing the propshaft needs realigning, but i guess it could be a bearing or has anyone any specific experience? I have little knowledge in this area and would appreciate some tips and guidance.

Many thanks in advance!

 

[robmcg]

Could be worn cutlass bearing. Could be a bent shaft. If the shaft is out of alignment, then it's your engine mounts that are shot. Time for a chat with your wallet!

 

[Victoria Sponge]

We had this problem on a 323, caused by something wrapped around the prop. Is it possible to check your prop without paying to have the boat lifted?

 

[cmedsailor]

Let me say, first of all, that a 2-blade prop behind the skeg will always cause some vibrations. A 3-blade is always smoother.
I also used to have many vibrations with my Beneteau 361. I replaced the engine mounts, replaced cutlass bearing (definately were causing vibrations), shaft alignment, checked that my shaft was not bent (very difficult job because you need to drop the rudder in order to remove it) and replaced the propeller with a 3-blade one. I now don't really have any annoying vibrations except some vibrations at around 1200rpm due to the engine, have nothing to do with the shaft.
So, my advice is to check the engine mounts and replace them only if they look in a bad condition, definately replace the cutlass bearing (especially if you can move the shaft a lot from the point it exists the shaft tube) and finally check the shaft alignment. Don't worry much about a bent shaft. The shaft is so well protected in the skeg that it's quite difficult to get damaged.

 

[mrplastic]

Thanks people, will investigate further