Replacing propeller shafts

[Shoalwaters]

I have built hatches above each of my prop-shaft packing boxes/seals, so access is now a breeze. Previously they were pretty much a rumour: you could see them by sticking your head down the centerline hatch in the aft cabin sole and peering sideways into the gloom. Actually reaching them was mission impossible.

Now that I can see what's going on, I find that the starboard shaft has corrosion just inboard of the packing box. I believe this is serious enough that the shaft must be replaced. The port shaft appears to be sound. On the next haul out I will remove both shafts for inspection and measurement.

I would appreciate input on the following:

1. Do you agree that the shaft in the picture must be replaced? It is 1-3/4" diameter and transmits power from a 160hp Yanmar. The pits vary from 0" to 1/16" in depth.

2. Inland freight on things 14ft long is not cheap, so I am looking at suppliers in Florida. I know of General Propeller and Deep Blue - any other suggestions appreciated.

3. This will be a good time to check the Cutless bearings. How do I do this? 1-3/4" shafts are not very floppy, so holding on and shaking might not tell me much.

T.I.A.

 

[Forkliftt]

Mike- it appears to me that the "sealing area" of the shaft is not pitted, and the pitting you have is the result of seawater easing past the packing in years past. If your concern is the strength of the shaft with this corrosion, I don't think that there is enough damage to cause concern. My Port shaft is similar, and has been since purchase in '06.

 

[psneeld]

I took mine to the busiest machine shop in the Cape May area that specializes in props/shafts for a new coupling...when he saw my pitting...very similar to the pics...he explained a method of filling it with a method I think is called cladding.

The problem with many trawlers with long shaft tubes that aren't run every week is the water gets anerobic in the packing and pits the shaft.

Here is a site that explains some of it.

http://highseasyachtservice.com/wp-content/uploads/2011/10/Marine-Shaft-Crevice-Corrosion1.pdf