Stern Tube Splining Lengthwise on Formosa 41

[James Diego]

This weird! I have a PSS dripless system on a relatively new shaft on Formosa 41. I replaced my transmission 100 hours ago with a used identical model and noticed no new vibration or noises as I have gone to Catalina several times since with no problems since replacing the transmission and I thought my worries were over.
After returning from Catalina over Memorial Day, I heard water running and my bilge pump going off. I looked and the bellows on my PSS unit had slipped back an inch from the rotor face and sea water was coming in. Had I not tightened the stern of the bellows sufficiently when I relocated it to remove the transmission? Maybe, so I readjusted the bellows and tightened the hose clamps to stop the obvious leak at the rotor but the some water still continued to flow from a horizontal slit or crack in the stainless steel rear tube just outside the bellows! Wow? Where did that come from? I readjusted the position of the rotor and the bellows to enclose the slit but the slit kept creeping down the length of the tube and I ran out of adjustment room for the bellows and the rotor.
Fortunately, I was able to wrap some self sealing silicone tape around the rear tube crack to contain the water flow but I don't know how that slit or crack in the rear tube came to be and how to keep it from happening again! Does anyone have any thoughts? I have been living aboard 14 years and this problem has got me stumped!!

[Auzzee]

That's a strange occurrence. The only problems I have ever had with PSS in twenty years is immediately after launching. Always I need to 'bleed' the bellows. I can't imagine how the slit came to be. Is it in the end of the stern tube?. If so, the only clue I can offer is that perhaps the tube was formed rather than cast and that the weld has given way on the join. There should be no extra pressure on the tube to cause a fracture. It will be a real nuisance to haul the boat just to effect a repair. And welding it in situ could come with its own significant problems.
Please keep us informed on what you discover and how you eventually overcome the problem. Perhaps Delatbel may have some input. I seem to remember he had a stern tube/seal problem in the South Pacific just a few months back.
Best wishes and welcome to the forum.

[James Diego]

Thx for your thoughts! PSS are pretty reliable and the tube is from 2001 after a major haul out. I am going to try other Formosa owners for their experiences. Thx for you contribution!!

[redbopeep]

I hope you are able to make a repair easily and quickly. I also suspect the tube to have been formed. I can't envision how many inches of the stern tube are bare/available for you to work with. There are clam-type fittings (with bolts on each side that clamp rubber onto pipes that experience these sorts of slits in water or chemical process plant use. They create emergency repairs and are effective until a permanent repair can be made. It is somewhat common to see very old galvanized steel water pipe to have lengthwise slits that look like a seam upon failure. Look at some of these pipe repairs to get the idea of the sort of thing I was thinking of https://www.google.com/search?q=pipe...w&ved=0CCAQsxg

[James Diego]

Thx, I will investigate that fix ! Appreciate your help!!