Carver Owners Forum

Hello. I'm an owner of a 2006 Carver 56' Voyager and have been dealing multiple tail shaft failures on both Starboard and Port side. Prior to owning the boat in 2018 both shafts and propellers were replaced. Since owning the boat in 2021 have experienced 3 tail shaft failures. Item that continues to be discussed is the shaft length and the distance from the aft strut to the propeller hub (currently 4" and overall length of shaft is 2.25" x 122"). Failures are occurring at forward end of propeller taper and 4" aft of rubber cutlass stern bearing. Would anyone have the original design length for the shaft? Thought is that when shafts were replaced in 2018 incorrect dimensions taken and propagating the problem.

Welcome to the forum.....curious have the failures been tested/checked as to root cause.......fatigue, shear, metal chemistry, corrosion etc.

Welcome aboard!
When the boat is moving, do you have vibration?
Are the props true?

A full testing and failure analysis of the fracture shaft was completed, and no material defect was found. The vibrations underway have not been abnormally high and there have been some misalignment corrections made but nothing significant. The surveyor feels the propeller overhang of 4" may be the root cause. However, we cannot obtain original shaft design documents but measuring this distance on another Carver 56 will give us an idea if this dimension was changed from original design.

attached is a photo of the measurement I'm looking for to help with root cause.

The shaft has to be removed anyway so remove it and take it to a prop shop, then tell them to fabricate one that's maybe 3" shorter. A 4" overhang seems excessive and I can see that being the cause. As long as you have just enough space between the prop hub and the strut to get a prop puller in there, that should be all the space you need, maybe 3/4 -1", a prop shop can tell you.

Remove the shaft that's still intact on the other side and set the broken shaft beside it to compare lengths, they might have been the same length but maybe not, I wouldn't assume anything. Something might have been changed in the past like the position of the engines, who knows. If both shafts look like they were the same length then you can use the good shaft to determine what the new length should be. I would recommend replacing both shafts.

Just to add to that, be sure to check that the new prop is installed correctly......fitted by lapping on to ensure proper prop hub to shaft fit.

Thanks for the feedback. A propeller blue fit test was performed on the last repair to ensure a proper fit. The 2 previous repairs I don't believe it was completed. The two shafts are identical length at 122" with 4" from the strut cutlass bearing to the forward end of the propeller taper since. They were manufactured from the same shop and same drawing was used. It sure would be nice to get a measurement from another 2006 Carver 56' to verify the correct length. This is the smoking gun the surveyor is leaning towards.

Fwiw, I saw a pic of a 48 Californian; the prop was within an inch of the strut.

Tksalerno wrote:Source of the post It sure would be nice to get a measurement from another 2006 Carver 56' to verify the correct length.

Just a thought , have a walk thru some boatyards that deal with larger boats with your tape.......just might come across a model the same as yours, or at least get a better visual idea of what is normal.