Rudder Repair recently completed

senara · **Joined:** 29 Sep 2008 20:01 **Posts:** 8

I have just completed a rather extensive rudder repair. I am posting this because I know there is a good bit of interest in this subject as this seems to be a problem area for most of the older vintage T37s. Mine is a 1980 37C. The rudder has been leaking, and the foam core has been saturated since I bought the boat over 2 years ago. Judging from the interior condition of the rudder, it had been saturated for years prior. I tolerated the saturated rudder - until I tangled with a sandbar near the entrance to Ocean City NJ and cracked the rudder in three places. Now I had no choice. I am certainly no expert, so I asked for a lot of opinions on the subject and reviewed this site for similar experiences. I finally decided to repair the rudder in place (not try to remove it). I made this decision because the steel plate and the bolts, and pintle holding the rudder all were nice and tight. No leaks around the assembly. Why cause a new problem by pulling it all out? With the help of an experienced friend, we made a nice clean cut all the way around the starboard side of the rudder to remove a large panel to give us working access. We saved the panel (or skin) to put back on once we completed all work on the inside of the rudder. We scooped out all the wet foam, including the small colony of barnacles and mussels living inside. We found that the rudder was mounted to the stock by being fiberglassed to two horizontal stainless braces or "tangs" for lack of better description. These tangs are glassed against the port side of the inside rudder wall, and welded to the rudder stock at the other end. I found that one of these tangs were working loose, as the original glass had somewhat delaminated. We rebuilt/reinforced this attachment by laying two layers of glass (using West System epoxy) over the tangs to re-form a new attachment to the inside shell of the rudder. We found a hole about the size of a dime right where the base of the stock terminates. It appeared that the forward edge of the rudder had been rubbing against a steel "tit" on the stock, and it had worn a hole there (apparently years ago). We put three separate layers of wet glass around that area and sealed it off forever from the inside. We then reinforced all the edges of the rudder by glassing them from the inside. Because the very bottom edge of the rudder had split, we poured a good bit (maybe a half inch) of epoxy down inside along the bottom of the rudder, and re-glassed the bottome edge from the outside also. Next, we built a form using plexiglass so that we could see through to the inside, and clamped the form to the rudder. We coated the inside of the form with paste wax to act as a release agent, then poured two-part foam in a series of three separate pours down into the rudder cavity. I decided on a 4 LB density foam rather than the 2 LB "A-B" foam sold at west marine. The 4LB density is super tough, and adds significantly to the structural strength of the rudder. Pouring the foam presented a few challenges, but the end result was excellent. We made the right decision to pour in three separate pours, because the stuff expands so fast that it gets away from you quickly. Also, the plexiglass form was a good idea so we could see how well the foam crept into the nooks and crannies. Also, the plexiglass allowed the foam to push out during the expansion process. If we had just poured into the top of a sealed up rudder, it would have burst open from the fast expansion pressure. We made the first two pours from the side of the rudder, using a piece of taped cardboard for a big funnel/chute. The final pour was made into the top of the rudder. We had previously used a hole saw to cut a 1.75 inch hole in the top of the rudder for this final pour. We found that the best method for the final pour was to create a big funnel using a piece of 1.5" septic hose and half of a cranberry juice bottle (the openning of the plastic bottle happens to fit perfectly in the 1.5 ID septic hose to create a funnel hose!) Once the foam was cured, we used a belt sander and grinder to fair out the foam and create a lip such that the fiberglass skin that we had initially cut away could be laid back in nice and flush. We wetted the back of the fiberglass skin piece, set it in, and then added two layers of fiberglass around the joint. We faired and fiberglassed the areas where the splits and breaks had occurred on the outer shell. The final step of course was grinding and fairing the cured rudder. Then, barrier coat and bottom paint and voila. You can tap all over this rudder and it is rock solid. I will attempt to attach pics below but not sure how. I hope this helps somebody else.

Tortuga's Lie · **Joined:** 27 Oct 2006 10:32 **Posts:** 827

Senara,
Excellent description of a nasty project...I guess this is something I am going to have to tackle before too long Crying or Very sad

Was the rudder divided in anyway into chambers? or was it one cavity once the foam was removed? It looks like the tangs are only on the port side of the rudder, so I guess opening it up on the starboard is the way to go.
How about corrosion? Did you notice any rusting going on? I suppose if this were the case, and the corrosion was severe enough, a whole-new rudder from Tartan would be warranted...any thoughts?
The one aspect of this rudder is that it is almost even with the bottom of the keel which I think is a bit too deep to keep the rudder protected in the event of a grounding. If one were to do a total rebuild, I wonder if you could cut off about six inches from the bottom and add a "roach" to the aft end of the rudder to keep the surface area the same. Just thinking.
Happy Holidays All Cheers

Tom

senara · **Joined:** 29 Sep 2008 20:01 **Posts:** 8

The rudder is not divided into chambers. But the support tangs have a brace piece that angles from the tang (about 1/3 of the way from the stock) and runs back to the stock on the Stbd side. This forms an off-center "V" shape with the open part of the V welded on each side of the stock. So these braces create a barrier within the cavity of the hollowed out rudder. We tried to calculate our pours so that the second pour crept all around these braces and filled the rudder up just past the highest tang/brace piece. As an aside, my daughter the engineering major calculated the interior volume of the hollowed out rudder to be 2.6 cubic feet. This was helpful to know when ordering foam. But take my advice, order twice as much as you think you need. We had a lot of waste. One batch expanded in the mix bucket before we could pour it. Burst the bucket. It would have been comical except that I had to re-order more foam and wait 3 more days! The tangs are indeed only attached to the port side of the interior rudder skin. We chose to cut the stbd side because it sounded more delaminated on that side. Turns out the reason was the tangs made it sound more solid on the port side. We were a bit lucky - I would hate to have the cutting drill tangle with the stainless tangs. All of the stainless steel, including the stock, was surprisingly stainless. It all looked really good and was in good working order even though it had been surrounded by saturated foam for many years. It was a time consuming job, but compared to the cost of a new rudder I would do it again.

Tortuga's Lie · **Joined:** 27 Oct 2006 10:32 **Posts:** 827

Senara,
Thanks, again...very informative for those of us yet to tackle this one! Did yo do anything to reinforce the area around the lower pintle? It seems that this area is susceptible to stress therefore would be prone to leakage??
Thanks, Tom

carl s · **Joined:** 31 Dec 2006 13:33 **Posts:** 90

Real good call on cutting the starboard side open. Nice work too. Have only had my boat for two seasons now and every year there is a little moisture in the rudder. The p.o. had the rudder rebuilt before going to europe with the boat. I think some water will always get in. I drilled a couple of small holes in the bottom to weep out moisture when it sits out of the water each winter. I usually get a cup or so out. I seal it back up in the spring with a couple of screws and caulk. I cant say where the moisture gets in but it always does. One humorous note, this fall when the boat was lifted out I noticed a fish fin flopping out of the lower hinged fairing. I pulled out a ten inch bass. Catch and release. Carl, Mawky ser 295

senara · **Joined:** 29 Sep 2008 20:01 **Posts:** 8

A ten inch bass?! Now that's a rudder story! or maybe a fish story. How many other brands of sailboats can claim to catch a good size fish with only a rudder? Tortuga - I think the pintle area that you are talking about is the same exact area where we found the dime-sized hole. It was on the forward edge of the rudder just where the stock sits on the pintle. The original glass was very thin there, and the hole had apparently worn through as a result of rubbing against a small extrusion at the base of the stock. If all boats were made the same way, then that is definitely a problem area for all.

DAEDALUSCAN · **Joined:** 09 Dec 2007 21:03 **Posts:** 114

Thanks so much for posting this. I am about to do exactly the same job. I will be taking the rudder out though, or at least the bottom bearing out as there is considerable play there. Really great to see inside before I attempt this. I had been planning to split the rudder into two halves, but I think that cutting of the (left I know now!) side is a much better plan. Charlie

senara · **Joined:** 29 Sep 2008 20:01 **Posts:** 8

Glad this was helpful. Just a couple of things - we used a "roto-zip" tool, I call it a cutting drill, to make a smooth controlled cut. Also, make sure to cut the right side (stbd) not the left. Good luck. Cheers

DAEDALUSCAN · **Joined:** 09 Dec 2007 21:03 **Posts:** 114

I did of course mean to say Starboard. Got that. Not knowing what was in there was my primary concern. Now I can see it before I cut.

NAM · **Joined:** 22 Jun 2008 10:54 **Posts:** 85

senara
I too have to re-foam my rudder and will, like you, do it insitu because I don't want to go to the risk of removing the rudder completely. I do have some questions though. With regard to fairing the foam prior to re-installing the outer skin, how did you insure a good fit between the foam and the inner surface of the skin. I expect at the least you butter the two surfaces liberally with thickened epoxy but did you take any profiles of the inner surface of the skin to transfer these to the foam?

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Rudder Repair recently completed

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