Rudder tube repair

[SimonD]

I have a leak from the rudder tube around the joint where it goes through the hull. She's being lifted this week to have the tube dropped out for examination. I suspect (or hope) that it's caused by the seal round the tube flange failing (the sealant is nearly twenty years old). However, it's possible that the flange to tube joint has fractured. If so, would it be possible and advisable to braze the flange to tube joint (it appears to be bronze)? If not, would having a new tube made up in 316 stainless make sense given that a replacement tube from the manufacturer costs around £800 plus tax and shipping!

 

[vyv_cox]

Brazing is certainly an option but you need to be certain of the composition of the tube and flange before selecting the filler rod, to avoid galvanic corrosion. You should be able to identify the composition by colour, using the info here Brasses and bronzes

Perhaps the easiest option would be to silver solder, when the filler would definitely be more noble. Alternatively, many brazing rods are nickel bronzes, which would also be noble to most likely brasses or bronzes.

What you must avoid is using a filler that is anodic to either the flange or tube.

 

[SimonD]

Thanks Vyv, that's very helpful. To be sure, I could call the manufacturer (it's Nimbus by the way) and ask them. What about the having one made in 316 stainless steel? I would have thought that as the rudder stock is stainless, that would be the best option (better than bronze I would have thought).

 

[Stemar]

The rudder tube on my Snapdragon was a lump of copper piping, as I found out when the rudder post wouldn't go back in. It had fractured within an inch or so of the waterline OTOH, it had lasted over 30 years. It was replaced with a section of wind surfer mast I found lying around in the club compound.

 

[vyv_cox]

Thanks Vyv, that's very helpful. To be sure, I could call the manufacturer (it's Nimbus by the way) and ask them. What about the having one made in 316 stainless steel? I would have thought that as the rudder stock is stainless, that would be the best option (better than bronze I would have thought).

I would stay with bronze if you possibly can. Stainless steel in fixed positions underwater is not a great choice.

I don't know your boat but if the tube is in wood then definitely do not use stainless.

 

[SimonD]

Okay, bronze it is (although a bit of scrap windsurfer mast has it's attractions!). If it needs repair, I'll check with Nimbus on the material used and go from there. Thanks again.