h25 "deflated" rudder

[Db421]

I'm fixing osmotic blisters among other things. the boat has been on the hard for about one year and I noticed that the rudder looks like it has deflated. Everything seems solid, but the shape is as if it had absorbed a lot of water over the years and since it has been drying it has lost a lot of volume. I have a lot of West System on hand with colloidial silica and microballoons so filling and fairing the depressions wouldn't be a problem. I just don't know if I'm opening a can of worms that is not necessary. If I were to fill the depressions I would want to either score the existing surface with a grinder to create some mechanical bond or possibly drill a series of shallow holes with a 1/8" +/- drill for the same purpose. the depressions are about 1/4" to 3/8" max. I think if it needs to be done, now is the time to do it but I just don't want to get into anything that is a waste of time at this point.

Any Ideas?

 

[JoeWhite]

As an ex-1984 H25.5 owner - I will say not to do anyting with it as it is a cruiser boat.
It will work just as good. You will be able to remove just the rudder in the future if it becomes a real problem.

 

[sandpiper10471]

I am thinking those aren't hollows. They are bumps. Probably from water absorption and freezing/delamination actions. Do the high spots sound hollow when sounded with an object like a hammer? A moisture meter test might be in order. See Mainesail's link.

 

[DianaOfBurlington]

Rudder core

First thing is to attach some sort of vacuum hose to it and to suck it dry. If there's still water inside it, you can't do much with it. Application of heat, like from a grow light or heat lamp, will help expedite the drainage.

So long as the stainless-steel flags welded to the shaft, inside the fiberglass, are still adequately 'glassed to the shell, this isn't much of a problem. Water is always going to get in there; you are a fool to think you can always keep it all out. Allow it to drain, suck it clear, and see what comes out. If it's water, mold and slime, fit a drain plug to the hole you drilled and forget about it. If it is chunks of foam, other core, rust and bits of fiberglass, you may have another problem; but I doubt that that's the case.

In future allow for draining the rudder whenever the boat is hauled for a season. This is what we have adopted after seeing dozens of 30-odd-year-old rudders come back loaded with slime and mold but with no other damage.

 

[Db421]

Thanks for the replies, guys. It looks like the best course of action is to basically do nothing. John, I think you've got it. The flags seem very securely welded to the post and the foam is solid. There was wear on the bottom of the rudder where foam was exposed. I covered that with epoxy sealant and then epoxy with micro balloons. I might put a drain there as you suggested, since it looks like water will get in somewhere. This boat doesn't get hauled very often. Do you think as long as she's in the water it will be fine until the next haulout?

 

[DianaOfBurlington]

Db21--

Assuming that all you have is core damage, due to water intrusion and age, not much more will happen to it till you haul it out. It will absorb more water, delaying (perhaps by much) the time to come when it will be dry enough to work on. You can always try sucking it out with a wet vac now as then. I would, however, be very careful to note any changes in the condition, whether it is getting softer or more distorted or not.

Ultimately, given that the fiberglass itself is basically sound, your task will be to suck out as much bad core as you can and refill it. This could even be done with the rudder in place. I would prefer to refill the foam so as to retain the rudder's designed shape.

But be careful-- if those indentations in the rudder's skin are soft to the touch (if you can distort them more than 1/8" or 3/16" by pushing with the palm of your hand) you could have soft 'glass in there, and that is quite a problem.