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Old 16-12-2008, 11:43   #31
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Pouring resin over glass stuffed in the voids will not add strength. I wouldn't do it. Just layer mat roving cloth in successive layers if that is what you want. Do no more than five layers at a time.
You've gotten a lot of advice from different sources so good luck in your project.
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Old 16-12-2008, 12:49   #32
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In some respects I am reluctant to offer suggestions but one thing you might consider is the possibility of using a very thin sheet of ply—say a door skin--to make a temporary cover over the exposed face of the rudder by cutting it slightly oversized (compared with the existing cut-out) and then using small self tapping screws around the edges to hold it in place. With this, and a couple of vent holes top and bottom, you could inject high density foam into the cavity (contact Foss Foam for the materials). Once that is set up the temporary skin can be removed (be sure to thoroughly wax the inside face of the door skin, or cover it with plastic stretch wrap so that the foam cannot adhear to it!) and the foam and inside face of the section you cut out, trimmed with a dremmal tool until you can get a good flush fit for the original cut out. That can then be epoxied in place and a new layer of glass or two laid over the entire face of the rudder (be sure to add matching glass to the opposing side to ensure you don’t end up with an asymmetric rudder blade!

FWIW…

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Old 16-12-2008, 13:03   #33
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I do appreciate the various opinions!

I would like someone to tell me why filling the voids with high density foam is better than filling it with thickened epoxy (after 1st adding mutiple layers of cloth/mat and resin over the internal structure)!!

What does the foam do that the thickened eopxy won't?

I would think that the thickened epoxy would bond better to existing outside skin, and new skin (layers of cloth) that I patch the hole with!

I realize that thickened epoxy isn't near as strong as cloth/epoxy layers, but it is stronger (better bond to skin) than foam, right?

The thickened epoxy would be less susceptible to water intrusion, and related damage in the future!

Just like to understand why some of these suggestions are being made.
I casn look into buying cans of foam, if they are available. It would certainly be cost-prohibitive if I have to have a professional foam person come out to inject the foam, as the boat/rudder are in a remote area, an hours drive from a larger center.
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Old 16-12-2008, 13:22   #34
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The difficulties I see are with the volume of epoxy you'll need (unless its very thickened with micro balloons, in which case you'll not be able to be certain that all of the voids are filled) which will generate an inordinate amount of heat; and, the near impossibility of ever being able to effect repairs to the armature at some future time if the voids are not completely filled and you do get water intrusion. Beyond that...?

Good luck whatever your election.

s/v HyLyte
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Old 17-12-2008, 11:52   #35
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... First, S/S steel does not work well when it is starved of oxygen. What makes S/S stainless is a chemical process that requires oxygen to work.
...
Is there some type of primer or zinc coating that can be applied to S/S to lenghten it's life in rudders?
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Old 17-12-2008, 12:31   #36
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I do appreciate the various opinions!

I would like someone to tell me why filling the voids with high density foam is better than filling it with thickened epoxy (after 1st adding mutiple layers of cloth/mat and resin over the internal structure)!!

What does the foam do that the thickened eopxy won't?
Try asking this question the other way around.........."why filling the voids with thickened epoxy is better than filling it with high density foam"

Thickened epoxy is not going to add any more strength. It will merely add weight. Foam will not add strength either but it will maintain buoyancy even if the rudder gets some water in it. You will find out the importance of that if you ever have to retrieve that rudder after a failure or have to remove the rudder with the boat in the water (I had to do that in Palmyra one time).

Fundamentally, all the filler does is help maintain the shape of the rudder and keep it from collapsing under pressure. All of the strength in the rudder should be coming from the framework. As the (very small) rudder shaft turns, it turns the framework of the rudder. The skin on the rudder gives it shape and volume, nothing else. It could very well be an empty shell or solid wood, it makes little difference in the function or durability of the rudder. It really doesn't even matter if the filler adheres to the fiberglass skin. All it needs to do is completely fill the void so that the rudder will maintain it's shape.

I still think that your weakest link is the diameter of the rudder shaft. There is a lot of room for flexing and very little surface to weld the frame to. I still don't know the size of your boat but I had a Columbia 36 one time and it had a 2 1/4" rudder shaft. Albeit, it was a spade rudder. Talk about a boat that was not meant for long ocean passages........I sailed that thing around the world. It was a New boat when I left NZ, after many modifications.

Anyway, when I was in New Zealand, I built a skeg (quite like yours), Through-bolted and glassed it to the hull. I then rebuilt the rudder, quite similar to yours except it had a counterbalance area under the skeg, forward of the shaft and used a 2" piece of solid S/S shaft with a bronze shoe on the bottom of the skeg that through-bolted from the bottom of the shoe up through the skeg and through the hull of the boat. I used siclon-bronze bolts & nuts. To remove the shoe, I merely had to undue the 2 cotter keys & nuts on the bottom of the shoe.

I sailed that boat nearly 35,000 miles and she took a beating on more than one occassion. The guy that bought that boat (Ramblin' Rose) from me in Hawaii got himself the finest Columbia 36's ever (re)built.
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Old 17-12-2008, 15:30   #37
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Kanani - Yes, I do realize that foam is the norm, and that epoxy would be heavier. I thought that the additional bonding to the "patched" skin may be worth considering. I will never be removing the rudder underwater / in water, as the gudgeon is one piece, and must be removed, by cutting a lot of glass out, before dropping the rudder, so weight is really not an issue.

Re: the rudder stock diameter - yes, it does seem a bit small, but it can absolutely not be compared to the 2" + thickness of a spade rudder, which is relying on the one point where it passes through the hull, to absorb all of the pressure, and weight of turning the boat. I am no engineer, but common sense would tell me that having the rudder suppported strongly at the bottom, on the skeg gudgeon would likely take 90% of the strain off of the shaft, as it passes through the hull.

What you did in adding a skeg / gudgeon to a spade rudder, with a large diameter shaft, is certainly making it bombproof!
However, my boat (which is 30' long, displaces about 9000lbs) has lasted well for 30 years, (coastal use, not off shore), so I am not about to redesign it completely, by adding a larger diameter, rudder post - therefore requiring a larger diameter gudgeon, larger rudder tube, steering quadrant, etc. No, it worked well, and looked strong inside after 30 years, with no sigh of previous patching on either side of the rudder.

I also think the designer, knew a thing or two, when they designed the boat. I have never heard of a rudder failure on one, although there aren't that many of them out there.

I will look into the foam, as I do appreciate teh fact that it will do what I need. I will have to see what is available, in cans, etc. Not sure if it, high density foam, is readily available in the construction industry. Or, if they are limited to the low density stuff.

Thanks again for taking the time to respond!!
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Old 17-12-2008, 18:24   #38
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Kanani - Yes, I do realize that foam is the norm, and that epoxy would be heavier. I thought that the additional bonding to the "patched" skin may be worth considering. I will never be removing the rudder underwater / in water, as the gudgeon is one piece, and must be removed, by cutting a lot of glass out, before dropping the rudder, so weight is really not an issue.

Re: the rudder stock diameter - yes, it does seem a bit small, but it can absolutely not be compared to the 2" + thickness of a spade rudder, which is relying on the one point where it passes through the hull, to absorb all of the pressure, and weight of turning the boat. I am no engineer, but common sense would tell me that having the rudder suppported strongly at the bottom, on the skeg gudgeon would likely take 90% of the strain off of the shaft, as it passes through the hull.

What you did in adding a skeg / gudgeon to a spade rudder, with a large diameter shaft, is certainly making it bombproof!
However, my boat (which is 30' long, displaces about 9000lbs) has lasted well for 30 years, (coastal use, not off shore), so I am not about to redesign it completely, by adding a larger diameter, rudder post - therefore requiring a larger diameter gudgeon, larger rudder tube, steering quadrant, etc. No, it worked well, and looked strong inside after 30 years, with no sigh of previous patching on either side of the rudder.

I also think the designer, knew a thing or two, when they designed the boat. I have never heard of a rudder failure on one, although there aren't that many of them out there.

I will look into the foam, as I do appreciate teh fact that it will do what I need. I will have to see what is available, in cans, etc. Not sure if it, high density foam, is readily available in the construction industry. Or, if they are limited to the low density stuff.

Thanks again for taking the time to respond!!
I appreciate the point and I thought the boat was bigger than 30'. You're right.....non-issue.

Just one more tip........never say, "Never".
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Old 07-01-2009, 08:01   #39
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Follow-Up News

While this thread is somewhat dated and we do not know what Northeaster has done regarding his rudder, I had just discovered a rather distressing situation that has developed with our own.

When we bought our current boat in January, 2002, the rudder was damaged and needed repair. As I described in an ealier post to this thread, we removed one side of the shell, had the old foam dug out, the armature sandblasted and re-welded and had Foss Foam inject and mold new-supposedly high density foam in place. The removed shell was rebonded in place and the entire rudder resurfaced with new glass.

The resulting repair looked as follows:



The ruuder looked essentially the same on subsequent haul-outs in 2004 and 2006. On Monday last we had the boat hauled out again, and discovered this:



The port side also has some distortions but not to the extent of the above.

The skin of the rudder is entirely intact and there is no water penetration. However, the "high density foam" has evidently shrunk and sucked the skin in with it, ala-vacuume bagging. Our surveyor examined the rudder and commented that the above was something he had seen with Foss Foam rudder repairs in the past on "many occassions"! News to me!

We are now waiting to see what if anything Foss has to say about the matter given that the last rebuild was well over $3K USD.

FWIW, the bottom paint on the boat is Petit Ultima SR and is now 2 years, 9 months old in Tampa Bay waters. As shown, the bottom is entirely clean and without any growth (we do have a diver that wipes down the bottom with a piece of discarded carpet once a month but that had not been done since November). We were merely having the bottom inspected and redone in anticipation of our Spring cruise.

I shall post updates as to Foss Foam's response to this situation.

s/v HyLyte
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Old 07-01-2009, 09:32   #40
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I know in the old days some polyurethanes would powder...this really looks bad...I'm amazed the glass isn’t cracked.
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Old 07-01-2009, 12:31   #41
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Hylyte,

It must be very frustrating to have this happen after spending 3k on a repair. Did you look into a replacement rudder from Beneteau? Might actually be less, although I understand that now you are somewhat comitted. Best of luck.

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Old 07-01-2009, 12:37   #42
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Wow! How discouraging. Hope your repair people stand by their work and redo at no expense.
Kind regards,
JohnL
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Old 19-01-2009, 07:59   #43
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Further Up-Date

Having now thoroughly hijacked Northeaster's thread, I thought I should update our situation.

Subsequent to our last post, our yard drilled a couple of small holes in our rudder to see if there as any water penetration and to evaluate the situation with the foam core. A very small amout of water--less than a cupful-- was drained that probably seeped in around the rudder stock at the top of the blade. (Something that seems all but unavoidable with rudders of this type.) And, the foam had shrunk, or collapsed, which pulled the skin inward, causing the misshapen appearance in the second photo, in our earlier post. Never the less, the structure seemed intact and, with that, no good reason to reopen the skin. (The distortion proved to be less than the shadowing in the photo suggested.)

So, our yard filled the exploratory holes and ground the surfaces down to glass and used a West Systems epoxy/microballoon paste, reinforced with chopped glass strands cut from glass cloth to fill and recontour the blade:




And:



Following this, the blade was covered with a new layer of glass and epoxy, futher faired, and then covered with an epoxy barrier coat.

The all but finished blade now looks like this:



And:



At this point I'm guestimating that the repair cost will come in between $1,200 and $1,500 USD. Unfortunately, the yard has indicated that whereas the failure was not their work, they will not pick up any of that cost. And, thus far, we have heard nothing from Foss Foam even though it was their foam that failed. IOW, we may be stuck for the entire cost of the repair.

s/v HyLyte
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Old 19-01-2009, 09:12   #44
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Hylyte - no problem about the highjacking. I will likely post some updates in a couple of months as well. I haven't worked on it lately - will attack it again in a couple of months!

Sorry to hear about your rudder! Good that it did not turn out as bad as first thought!!
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Old 19-01-2009, 12:32   #45
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Rudder leaking

Hi Kanani
I have followed this post real closly as I had noticed on my last haul out the rudder leaking for quite some time I was concerned but had no movment between 2 1/4" shaft and rudder Skeg hung similar to yours
It was with relif that I read that this is not uncomon and not a huge concern thanks for sharing your experiance. My 2 1 /4 " rudder post has a SS blade welded to it about 8"W by 12" long but I am not sure how the rest of the rudder is attached Thanks again for sharing you experiance.

"It's pretty hard to find a boat out there that doesn't have water inside the rudder. It has been my experience that every boat that I've ever drilled a hole in the bottom of the rudder drained water for quite some time. I don't feel that is a huge concern. The blade moving independently from the shaft is a big concern. The only way that can happen is if you have a broken weld or the F/G has become completely detached from the frame."[/quote]
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