Wet rudder maintenance

[westerly33]

When I bought my current boat she was out of the water for quite some time and the rudder was dry but with expansive voids inside the foam. I drilled number of holes in the shell and filled the voids with Sikkaflex. I made grove around the rudder stock and filled it with Sikkaflex too. The rudder was covered with several layers of high build epoxy and antifouled.

Next time the boat was out of the water the rudder was wet. I drilled a hole at the bottom of the rudder and drained the water. Now the rudder is dry again.

Stainless still is prone to corrosion in wet anoxic conditions, which means the rudder frame inside is in danger of desintegration. On the other hand, it is very difficult to seal the rudder since the air inside expands and contracts with water temperature and the rudder shell works as a pump until it sucks enough water to equalize the presser inside and outside the rudder.

If it is true, maybe it is better not to seal the shell and make arrangements for better rudder ventilation, so that more oxygen will enter the shell with water and corrosion will be less active?

[mitiempo]

I think it would have been better to fill with thickened epoxy and seal with the same. Then glass over with epoxy and cloth before painting. The sikaflex seals but doesn't create a solid structure like epoxy would. Some people drill a hole at the bottom of the rudder and plug it when in the water and remove it during haulout to promote drainage. I think you don't want water in the rudder at all and would do my best to prevent it. If the rudder is solid epoxy and cloth outside and foam filled inside there should be no water penetration. And no real place for water inside.

[Pub911]

You can also split it open like a clam and see what's going on, but that means dropping it, which can be a big job.