Copper stern tube?

[Saltram31]

I needed to replace the flexible coupling and cutlass bearing. I have never really bothered to check the stern tube as it is below the fuel tank. This time I removed the fuel tank and paniced when I saw the colour of the stern tube. I thought it had dezinced but on closer inspection saw that it is completely made from copper. There is no pitting or any other indication of potential failure.Its been in the boat since being built 35 years ago. Was copper the norm in those years? I still have all the original receipts for the boat and and saw that the tube was supplied by Bukh. (Bukh motor)

 

[burgundyben]

Shaft logs are lined with copper tube on my boat. 45 years old. They do rot out eventually, it happened on my previous boat from the same builder.

 

[Arcady]

They do rot out eventually, it happened on my previous boat from the same builder.

Indeed they do. Cautionary tale here: https://fjordms33.wordpress.com/2016/02/15/sohvi-stern-tube-failure/

 

[Saltram31]

Indeed they do. Cautionary tale here: https://fjordms33.wordpress.com/2016/02/15/sohvi-stern-tube-failure/

Thanks for the link. Will change mine at next lift out for peace of mind,even though it seems to be in good order.

 

[vyv_cox]

The owner in the link says his was bronze. I have not come across one made of pure copper before. Copper household pipework suffers pitting in acidic waters, not normally a problem in seawater but if set in wooden hulls the pH may be low.

 

[burgundyben]

The owner in the link says his was bronze. I have not come across one made of pure copper before. Copper household pipework suffers pitting in acidic waters, not normally a problem in seawater but if set in wooden hulls the pH may be low.

Quite right Vyv, ordinarily you would expect it to be Bronze. On the Fairey motorboats, Huntress, Huntsman and Swordsman, the pipe is copper. Looks like the old schedule K household pipe but in 2" bore.

 

[Saltram31]

My hull is grp. Vyv, I replaced the old packing with carbon packing at the time I replaced my cutlass bearing,so hopefully it does not contribute to a faster decay.