Re: [Electric Boats] Re: Albin Vega direct drive?

 

Thanks for the responses re vibration.   My thoughts are that if it is not a unbalanced prop or very worn cutlass bearing then it might just be the two points of flexibility that the system has.   The cutlass bearing is never really a tight fit even when new right?   So there is some amount of angular movement there?  The double sprocket chain coupling that connects the prop shaft to the Thunderstruck reduction is another point of movement.   Perhaps when running and getting a lot of thrust from the prop (I measured 180 pounds of thrust produced at the dock by the prop when delivering 3000 watts to the Sevcon controller), these two couplings are sort of wobbling in phase with each other, causing the thrumming vibration at the higher power levels?

When the boat had the diesel engine in it, there was only the one point of flexing, the cutlass bearing.   The connection from the prop shaft to the motor transmission shaft was a rigid one, with a four bolt flange.   The mass of the diesel engine at 400+ pounds also probably had a big dampening effect on any shaft thrust or vibration.

So...I am thinking about adding a pillow block bearing between the end of the PSS dripless seal and the chain coupler, to lock down the position of the shaft.   Our shaft is 1 inch diameter.   The bearing would need to be able to handle axial and radial thrust, so perhaps something like a tapered roller bearing...

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Posted by: lightdoesnotage@yahoo.com

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