We are on the hard at Sea Marine in Port Townsend. For three weeks now. We should be floating again on Friday. We have been chasing vibration problems for a while. This yard visit should resolve most of it. Fingers crossed.
Three years ago we we replaced the original bronze prop shaft on the port side with a shiny new stainless steel shaft. At the same time, we replaced the cutlass bearings on both sides and had the props tuned. When that was done, all seemed pretty good. The boat has always had a bit of vibration. We attribute that to forty years of use. Last year, I replaced the engine mounts and did the best I could to align the engines and the shafts.
The work order for this trip was to check the engine/shaft alignment and adjust as necessary (do it right – instead of how I did it), and check the shaft seals. The starboard side leaks when the shaft turns. I suspect this is was the result of my less than accurate shaft alignment.
As I understand it, the engines and shafts should be aligned to within .005″. I managed to get that to about .030″. Not good enough, but better than I expected.
The Sea Marine folks pulled the starboard shaft and found it worn and bent a bit on the taper end. They also found the starboard prop was missing one of the nuts. The jam nut and prop were loose. The retaining pin was the only thing holding it all together. Weird.
You can see the wear below.
So now we have a shiny new stainless steel shaft on the starboard side to match the port side. And the prop was re-pitched slightly to match the other side. Why they were different, I do not know.
More to come when we pick up the boat Friday!
I think you will find the reason for the different prop pitches has to do with your engine transmissions. One is set for forward and the other is set for reverse since both engines rotate the same direction. In other words, you don’t have a counter rotating engine. The transmission gears in reverse are slightly different, hence the need for different prop pitch.
Hi Don. You are most likely correct. Perhaps it was poor wording on my part. They re-pitched the prop to the correct pitch (whatever that is) – not necessarily to the same pitch as the port side. The boat runs great now. The run back to Poulsbo was smooth and vibration free.