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Discussion Starter #1
I've read and heard of people drilling a small hole at the bottom of their rudder to allow any abosrbed/ingressed water to drain while the boat is on the hard.
The hole is filled with MarineTex or the epoxy before splashing.

Does anyone really do this? If so, what are you experiences?

Josh
 

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Just getting the water out doesn't address the damage that it has already likely done. Delaminating the rudder from its post and web is a nasty problem.
 

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You can fix it!

I will be dropping the rudder for a cutless bearing replacement. Time to do a shaft inspection, too!! I have already repaired the skin of this boat's rudder. When I got the boat the entire surface of the rudder was spyder cracked. I assumed it had filled with water and frozen. It had been on the hard for several years in New England. The cracks were evenly distributed. I drilled some holes and drained a lot of water. I ground down the cracks, not through the skin, filled them with an epoxy resin and tediously teased into place fg mat, then added a layer of fg mat in epoxy resin over the entire skin. I carefully sanded and faired the surface leaving a continuous epoxy/mat layer surface covering.

The stuff that drained out of the rudder the first year was septic. I was going to drill out some large plugs for inspection at that time but decided to see how things looked after a season of coastal sailing. I did inject (GretStuff) into the holes I had drilled using a long feed tube placing the foam deep in the holes. I used a long 3/8 bit and drilled up from the bottom edge of the rudder as well as some holes up high. I repeated the hole drilling and foam injections for a couple of years and quit after no drainage or apparent "wasted" core showed up. No signs of the original surface cracks have ever appeared. I closed the holes with epoxy paste each time. It has worked so far! It looks perfect after 5 years of service and storage here in Maine.

Now I guess it is time for an exploratory dissection since I can take the rudder into my shop and have a careful look.

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Funny, but I was just looking at a post from two years ago, where I rebuilt my drive line, and I had to drop my rudder. You can read about that here: http://www.sailnet.com/forums/gear-maintenance/80089-contemplating-drive-line-overhaul.html.

What I did not delve into in that post was how I addressed the water intrusion.

It was clear to me that the water was penetrating the rudder, where the rudder shaft met the rudder, here;


The red stuff is not corrosion, but red grease for the rudder tube.

You can't see them, but there were small stress cracks around the shaft (or is it the stock?:confused: ... whatever...) I believe that water was penetrating these small cracks, and travelling down next to the tube, and collecting in the bottom of the rudder.

What I did to address this is I took my trusty Dremel and routed out a ½" deep, ¼" wide channel in the rudder around the stainless steel tube. The channel was "V" shaped. I then filled this trough with the dreaded 3M 5200, and set the UHWMP spacer that you see in the pic above in the 5200. Think of it as bedding the spacer. I then re installed the rudder on the boat.

In the past two seasons, all has held up fine.
 

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Drilling, draining and filling the holes are fairly easy, but Minnewaska's comment is the vital one. Water in the rudder is only a problem if you get hard freezes. Drill and drain solves that one. Filling is a simple epoxy/fibreglass job. This keeps the rudder from splitting.

BUT the real danger for most boats is rudder-post delamination. At very least you should stop the ingress. You should also test the rudder/post bond. If there is any hint of movement, or if the water coming out of the holes you drill are rusty, then you probably have a bigger issue. You probably need to drop the rudder, split it, rebuild the interior structure, and then reseal.

That is a big job!

EDIT: eherlihy's solution might be another option to a full rebuild. If you split and rebuild, then you know exactly what's going on. But it is a big job (depending on the size of your rudder).
 

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Discussion Starter #6
To be clear, I don't have any current water ingress issues that I know of. I just read that people do this routinely as a preventative measure and was wondering if its common and any what are the pros/cons.

Josh
 

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To be clear, I don't have any current water ingress issues that I know of. I just read that people do this routinely as a preventative measure and was wondering if its common and any what are the pros/cons.

Josh
Josh--

A simple test for water ingress is a very small hole at the base of the blade. A shop vac can be used to pull a vacuum on the blade and evacuate water, if any. A tight fit for the vac hose to the blade can be assured by cutting a 2-3" length off the end of pool noodle with a center hole a bit smaller than the hose nozzle that one works over the hose nozzle (for a relatively air-tight fit of the hose nozzle against the blade). If one gets any measurable water out of the blade with this arrangement, further investigation is required. The two dangers of water ingress are delamination of the blade skin from the core due to freezing (for those subject to freezing weather) as noted by others, above, and the possibility of corrosion/weakening of the connection between the blade armature and the rudder shaft/stock within the core. If nothing is found, the inspection hole can be refilled with thickened epoxy and then covered with a small patch of glass. The foregoing test might not be a routine matter but something one would undertake if one or one's surveyor had any suspicion that something might be amiss with the rudder.

When we first bought our boat, the foregoing test extracted about a pint of water from the blade. Subsequent investigation (removing a section of the skin) revealed localized delamination but even more so, corrosion of the armature. With this, the entire skin on one side of the blade was removed, the damaged core removed, the damaged armature shot blasted and then repaired, reinforced and epoxy painted, the core replaced and then the exterior skin re-adhered to the new coring and a new layer of glass applied to the entire rudder. The repair took about a week (including drying/curing time) and cost something in the neighborhood of $3600 (the skills required being beyond my level of expertise). The foregoing repair was not inexpensive but was far preferable to the possibility of loosing the use of the rudder at sea, halfway between home and heck's half acre, and the costs that could entail.

FWIW...
 
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I drilled holes in bottom of my Tartan 30 rudder to drain at winter layup and sealed with epoxy in spring for first two years of ownership. Core still seemed to fill with water during season even though drain holes sealed. For last 12 years of ownership have left drain holes unsealed. Reassuring is that drain water always comes out clean--no rust-- and surface shows no sign of delamination.
 

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It's very hard to keep a rudder completely dry forever. Somehow the rudder post must penetrate it and it's almost always underwater. You can epoxy these drain holes well, but that seem is still suspect.

However, once you've found enough water to drain out by drilling a hole, you have to become concerned for the corrosion of the post and web inside, or the structural separation/delamination. It's a real lousy problem.
 

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Thanks for reply. If/when I do serious cruising, I may well cut an inspection hole at a post/rudder arm bracket just inspect weld integrity for corrosion. Loosing rudder action very scary thought. In the mean time, I'm relying rust in drain water to as telltale to any corrosion taking place and the fact that rudder does not seem to have any play or visible delamination. I guess that this relys on the fact that corrosion underwater in absense of air is limited. Also, I'm in fresh water, Lake Michigan.
 

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.....I guess that this relys on the fact that corrosion underwater in absense of air is limited.....
Corrosion of stainless steel is caused by this, as stainless relies on a microscopically thin layer of oxidation to prevent the steel from rusting. This layer does not form or replenish in the absence of oxygen, therefore, the iron is at risk. Read up on crevice corrosion.
 

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E and I have huge rudders.

It behooves us to take care of them LOL
 

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The rudder armature has failed on two of the nine Tartan 30's at the Club where I'm a member. As I recall, both required significant repairs to the skeg shoe while the rudder was off.
 

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If rudders eventually fill with water, why not design a rudder that can be submerged and inspected. I'm thinking a few basic structural components such as ribs and spars(rudderpost) with a covering of plastic, riveted on. The shape is the same and with holes on the top and bottom it could fill with water, then drain when hauled out.

Anyone see anything out there like that? With a roll of plastic, rivets and some spare ribs you could even keep a spare rudder stored on board unassembled.


Wing design
 

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Rudders that do not suffer from water absorption have been designed and built. The problem is that the stainless rudder post and armature inside and the fiberglass covering it have different expansion rates, making it impossible to seal the fiberglass to the rudder post for the long term. The post and rudder have to be made of the same material. Carbon fiber rudder posts are used on some boats and don't have this problem. Expensive though.
 
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