alignment problems on 28 Flush Deck

[bobm]

Recently replaced a worn shaft with new. Had prop reconditioned and balanced. Good cutlass bearing and new Tides dripless stufing box. Replaced worn rear engine mounts. Hinkley boat yard in savannah,Ga. did the work.They also had the coupler trued. Returned to me saying engine and shaft aligned. Noticed vibration between 1150 and 1280 RPM when running my Volvo Penta 2005 D6 310 hp motor. Put a dial indicator on the shaft. Ran true at the coupler but was out by 15 thousandths at stuffing box/ shaft log. Boat yard says it is a bad design and they don't think they can align it properly. Mainly complained about access to motor mounts, particularly front. I made them agree to try again.

Has anyone had this problem and result on any other 28 Flushdecks? Is it truly a defective design ? Anyone have any advice as to how to proceed? Any suggestions will be appreciated.

[RobS]

I've been active on AOG since 2007, mostly in the Maintenance forum and this is the first I am hearing of this so I would say it is unlikely a defective design, maybe not the best design, but "defective" ? sounds like a case of passing the blame.. BUT a "worn" shaft, what was that about?

[bobm]

I believe the shaft was "worn". I was told there would have to be some welding done to correct the 22 thousands difference which I assume meant building up a narrow spot. Not sure about this. When I bought the boat one of the motor mounts was corroded enough to have a broken part. The shaft was not aligned so the Tides seal was leaking from shaft movement at high RPMs. There are 1400 hours on the motor. I know the cutlass bearing was replaced last April, probably due to this misalignment problem. This is my first inboard deisel boat so I am not familier with the likely hood of the shaft wearing. The estimate for fixing the shaft was $800 more than a new shaft so I chose that route.

[bobm]

ROBS. The boatyard comment about the bad design may be a reference to the difficulty in reaching the forward engine mounts for adjustment. I don't think they put a wrench on them at all.

[RobS]

Now that makes more sense that the shaft was worn due to the alignment/bearing issue. At the Boston rendezvous I boarded a 28 flush deck to see how tight it was at the front of the engine when the owner was explaining to me how he was having a problem with the engine eating belts and not being able to get proper pulley alignment due to the very tight work-space. That was a Volvo. But that would correspond with the front engine mounts being very tight as well. Maybe a FD owner who has done his own alignment will chime in here. Sometimes it requires cutting into the boat to gain access to something the builder did not allow for and then to fix the cutout with a deck plate, access/hatch door, etc etc so future access is then there. Make sure they get it right this time or it will only lead to more of your $$ down the road. Those misalignment stresses could effect the gearbox too.

[bobm]

Thanks RobS. I am hoping someone who has experienced this alignment will reply with some helpfull direction. I am going to try to see how to get better access to the front mounts. Ideally I would like them to try the alignment again with the boat in the water and see if the new shaft might come back to within tolerance. Otherwise i think it will have to be hauled out and the shaft removed and straightened and then re aligned.