Hi folks. Anyone else had trouble with their rudder post beneath the quadrant on their yacht (especially a NS38) ? From the relatively fresh gelcoating there seems to have been a previous repair but there is still a small leak on the starboard side coming through the gelcoat halfway down between the quadrant and the bottom of the hull and there also seems to be a rusty leak down the port side which appears to originate higher up on the aft side but dribbling down to port. Not sure why there is both green, which presumably is from brass, and also rust which must mean steel? Any help gratefully appreciated.

There could be a stainless steel tube that is burried under the fibreglass and is corroding away. Water may have found its way between the fiberglass and the ss tube and crevice corrosion has started rust. The expanding rust puts stress on the glass and causes it to crack.

Ramona said..
The gland is the old style bronze unit with the lock nut on what should be a bronze tube with the thread at the top. The thread is obviously bronze but why it appears to be rust there I have no idea. Fibreglassing metal is always going to fail eventually. I would open out the crack where it's leaking a bit and jam some Selleys Knead it in there and go sailing. Sometime in the next 20 years or so do a better repair with epoxy.

Ramona said..
The gland is the old style bronze unit with the lock nut on what should be a bronze tube with the thread at the top. The thread is obviously bronze but why it appears to be rust there I have no idea. Fibreglassing metal is always going to fail eventually. I would open out the crack where it's leaking a bit and jam some Selleys Knead it in there and go sailing. Sometime in the next 20 years or so do a better repair with epoxy.

Thank you very much. I have had it suggested to me that perhaps the rust at the top is where there was a grease nipple which has rusted out. I will clean the area up and wire brush it then scrape around and try to verify that. Although the tube looks to be bronze which has been fibreglassed over I am a bit worried that the rudder stock itself which must be within the bronze tube may be stainless steel which may be suffering from crevice corrosion which is then leaching out the top. I will look for the remnants of a grease nipple and then probably do what you say for the small green leak half way down the tube.

Jolene said..
There could be a stainless steel tube that is burried under the fibreglass and is corroding away. Water may have found its way between the fiberglass and the ss tube and crevice corrosion has started rust. The expanding rust puts stress on the glass and causes it to crack.

Thank you, I will try to confirm what the rudder stock is made of but I'm pretty sure the tube surrounding it is glassed over bronze.

2bish said..
Hi Jules, my boat has a similar set up, but no nut on top (top is well above waterline). It had a grease nipple that was completely corroded away and looked very similar to what I'm seeing in the bottom two pictures. Regarding the first pics, I see what looks like a bristle from a wire brush stuck there, could that be enough to bleed some rust onto that patch I wonder?

Thank you, how did you get the nipple out and did you replace it?

Ramona said..
The shaft looks to be stainless steel. Inside that "nut" is a taper that will have several packing rings that are pushed against the SS shaft to stop the water from coming up. The bronze tube will normally be full of water up to the waterline in this case and the gap around the shaft will be something like 3mm or more. Forget crevice corrosion! The packing will hopefully be teflon lubricated by a bit of grease. If it had a grease nipple it would be a bit of a waste. If you pull the nut to check the packing rings every 10 years and add a bit of grease that will be ample. If it was on a prop shaft then a nipple permanently connected to a grease gun and give it a squirt every day or so on a workboat that is working long hours every day is the norm. Steering on a yacht will see little action.

Thanks heaps. Puts my mind at rest.

It does look like a corroded grease nipple The rudder stock is probably stainless as others have mentioned but it does have a bit of an aluminium colour to it, so check that is not the case as it will corrode very fast in the presence of copper (bronze).
In any case for the long term even with stainless, it is best to have the same metal as the less noble will corrode in the presence of an electrolyte (seawater).
Next time the boat is out see if you can determine the lower bearing material, fine if it is synthetic.

Are you sure the leak is coming from the green bit down the gelcoat? It would be pretty likely the stuffing box gland is leaking a drop or two. Seawater should be on the inside of the bronze rudder post/tube, no seawater should be getting on the outside, except through the gland. Otherwise there would have to be a crack there.

If the rudder protected by a skeg? Given the repair, the rudder might of hit something and damaged the rudder, rudder stock and tube/post assembly. It is doubtful the stainless/aluminium rudder stock is original, as it would be the same material as the tube.

Cant help with the leak but as Ramona said its an old bronze packing gland. The larger ring nut on the bottom is the locking nut. You need to loosen this to be able to tighten or loosen the top nut that pushes the packing in.
By the looks of it it hasn't been serviced or the packing changed for a while. I would imagine that is why there is loads of grease smeared around the the top as it leaks.
So whilst you are at it clean up the thread under the locking nut with a wire brush and some WD 40. Loosen( looks like fun in that small space) the locking nut and grease it up.
Next time you are out see if there is a leak at the post. It should drip a little when in use. Once every few seconds. If its leaking more tighten the top nut. Only 1/8th of a turn. Wait 10-15 mins and see.
One day when you are out of the water change the packing.
I kept a metal oil filter changer on the locking nut to be able to undo it when needed.

Ramona said..

Jolene said..

Hopefully it is a bronze tube, I have seen quite a few stainless tubes that corrode away.

The thread is bronze so one would have to presume the rest of the tube is the same.

In the case of a rudder gland, it would be above the waterline with the boat stationary. Water may go up the tube when the boats at speed depending on the lower bearing configuration, but it would be only a small amount.

Just go sailing.

It's an old yacht with a spade rudder, shaft is stainless with tangs that are bonded into the rudder mould, before the other half is joined, it's a standard way to build them, they are usually strong. I would however drop the rudder out next time you slip and fix it all up. The recent coat of white flokote is telling you something.

julesmoto said..

Perry500 said..

Ramona said..

Jolene said..

Hopefully it is a bronze tube, I have seen quite a few stainless tubes that corrode away.

The thread is bronze so one would have to presume the rest of the tube is the same.

In the case of a rudder gland, it would be above the waterline with the boat stationary. Water may go up the tube when the boats at speed depending on the lower bearing configuration, but it would be only a small amount.

Just go sailing.

It's an old yacht with a spade rudder, shaft is stainless with tangs that are bonded into the rudder mould, before the other half is joined, it's a standard way to build them, they are usually strong. I would however drop the rudder out next time you slip and fix it all up. The recent coat of white flokote is telling you something.

Yes I am definitely suspicious about that relatively recent flow coat. NS38s have a partial skeg as shown here BTW.

Okay, I stand corrected, must have been another NS I saw, that's a good arrangement there.