Rudder cracks - '81 Cherubini Hunter 36

jdhohmann · Apr 6, 2015

I have seen this type of cracking before. Unfortunatly, it was bad news, It looks like the shaft might be trying to spin internal to rudder. and some delamination has occured. In that case we had to remove the rudder and have the fibreglass redone. SOme of it may have been for piece of mind some structural. Either way, the internal 'wings' where the cracking is occuring must be putting some undue forces on the fibreglass. I would get her fixed before she seperates once she is back in the water...

braol · Apr 6, 2015

You could always go the "inject and fill" route with epoxy. I did that on my rudder, first with unthickened epoxy and then some thicker stuff to follow. I also ground down my cracks until I got to clean foam and then just filled with epoxy and a layer or two of fiberglass. Rudders are under all kinds of stresses and as they get old you can get some internal delamination between old foam and fiberglass where gaps can develop and cracks form. Injecting epoxy should stiffen-up the inside of the rudder, as well as seal it from any outside water intrusion.

braol · Apr 6, 2015

The rudder is a round shaft to which is welded a rudder-shaped frame made of strip or thin bar steel. Around this frame is a core of two-part foam ("epoxy foam" would be the best description) with a fiberglass skin. (I may be wrong, buy I assume that a new rudder frame is placed in a closed mould into which is poured the liquid foam. When the foam hardens, the mould is removed and the rudder is then smoothed and glassed over.) The foam is REALLY hard and provides strength without being too heavy, the fiberglass just reinforces this even more and also protects the inside from getting wet. The danger to a rudder is that it develops a crack, water gets in, rusts the frame and the welds holding it to the rudder tube, and then one day you turn your wheel (or tiller) and the rudderpost breaks free of the frame and foam and there you are with a floppy rudder hanging out the back.
I'd say that the fiberglass is several layers thick. What I noticed on my rudder is that some of the foam had either shrunk or that there were some voids where the glass and foam are not touching. These gave a dull sound when rapped with a small hammer. I had also developed a vertical crack on one side of the rudder. I simply ground away the rudder glass and foam around the crack untilI reached virgin foam and then filled the crack with epoxy resin, a litle bit of fiberglass cloth, sanded it smooth, put on a barrier coat and that was it. Another place to develop cracks is where the rudder post enters the rudder, then water can get in. i had this also. What I did for that is to drill some holes near the bottom of the rudder to allow water to drain and the rudder to dry and then filled the holes with epoxy.

You can inject epoxy with a syringe (West brand sells these). Just mix the resin, suck it up with the syringe, and inject. It's best to drill an "outlet" hole nearby to allow air to escape. When epoxy bubbles out this other hole (and the hole is best to be higher than the injector hole...air rises...) the void is full. I like to duct tape over the injector holes so tha the epoxy does not run out.

Jim Legere · Apr 6, 2015

When I had the pre-purchase survey done on my H37C (way back in 2001) the surveyor noticed similar horizontal cracks on my rudder. Long story short, it became a point of contention in the sale and we ended up factoring the cost of a new rudder into the price. Foss Foam in Florida still makes rudders to order for our old Cherubini Hunters. I seem to recall a new rudder was around $1500 back then. Foss Foam's website has some good pictures of how the rudders are made:
http://newrudders.com/?page_id=12
If the cracks are really worrisome, you could always remove the rudder and split it with a zip cut wheel on a grinder, inspect the SS frame, make any repairs, and epoxy everything back together. A big job but doable. I kept my old rudder, just in case I ever wanted to do this but I have yet to tackle it...:lame:

pvtpotter · Apr 6, 2015

Personally, I'd grind that out, get to glass, and let it dry. Then come back with some fiberglass cloth if necessary, but you should only have to fair it with a fairing filler and throw some barrier coat on. Have you looked at your hull too? I sanded this weekend and I kinda freaked out. I have stress cracks like that on my hull in many places. Rudder looked great though. Maybe someone already did the job. I know, rudder issues are worry some.

Try not to drop the rudder. I have done many jobs like this with the rudder in place. Looks to me like you can just grind, fill and barrier coat. Not too bad. Let us know your fix. Thanks for posting.

"Rudder's shot away sir, the steering don't answer." -Master and Commander

smacklin · Apr 6, 2015

What are we looking at in the photos in the white ? Did you sand right down to the gelcoat or is there still multiple layers of epoxy (ie Interprotect 2000) still on top of the Gelcoat ? Are the cracks just the epoxy layer or right down thru the gelcoat ? I ask because in photo 3, the triangle crack looks even whiter beneath.

Something caused those cracks and they are not small by any means. They appear to be fairly regular across the top half of the rudder. I am also of the opinion that the glass skin on the port side has seperated from the foam inside and the shaft frame is flexing inside and damaged it by pushing out on the fibrerglass skin. Maybe the steel frame is tabbed (glassed) to one side of the skin only --- hence why you only see flexing on the single side.

Do you see any water seeping out ? You might consider drilling into the core 2 inches from the bottom and see if water pours out.

Personally if it was mine, I would not put that rudder back in the water without knowing.

Maybe send your photos to FossFoam and ask them for guidance.

Good video series here to show you what is inside a rudder and how they are repaired.

https://www.youtube.com/watch?v=MRXNnFx7DBQ

Sailorjack · Apr 6, 2015

tmjb
I had similar cracks on my 37c rudder except mine were on both sides but mostly one side. When I hauled the boat for the season I drilled small holes in the rudder and let it dry over the winter. The foam that came out of the holes was dry. In the spring there were some rust stains around the holes I had drilled. I ground out the cracks and filled them with epoxy and glass. The next fall I I removed the rudder to do some exploratory surgery. I cut into the rudder to expose the framework. I was expecting rusty mild steel but I found stainless in good condition and again dry foam. I replaced the cut out pieces and ground out the cuts and fibreglassed over each cut.Then I fibreglassed over the whole rudder and coated with gel coat. I haven't had a problem since that was back in 2007. I suggest you drill some small holes and check on the foam that comes out. You can fill with epoxy to repair the holes. The repair Jim Legere describes is possible but it is a big job. The fibreglass and the foam stick together very well so it isn't easy to split the two halves apart.
Good luck.

Tim M · Apr 7, 2015

Was the rudder exposed to the sun on only one side for 18 years on the hard? This looks like degradation of the gel-coat from sun and weather. On our boat the rudder had to be rebuilt professionally because of sun exposure after less than a year on the hard after being in the water for 30 years. This was the surveyor's opinion and the repair work confirmed that it was the case. I'm sure water ingress was the culprit but the damage that resulted on only one side of the rudder because it was the side exposed to the sun was much more raised in larger flat sections with 8 - 10 large cracks and not multiple hairline cracking like yours. It also followed the framework of the rudder to a certain degree. It doesn't look to me like damage caused by a turning shaft either - unless the whole interior framework is banging back and forth in there. If the rudder is still solid with good integrity of the fiberglass, sand the paint off and coat with several coats of epoxy after some 3M filler if it's not smooth enough. From my experience, boatyards and owners often neglect to properly care for the rudder as compared to the hull. Maybe initial barrier coats weren't applied and maintenance coating was minimal. Extra cloth won't hurt but might be overkill. Good luck.
Tim

DannyS · Apr 7, 2015

I've posted this many times, but always happy to post again. http://forums.oday.sailboatowners.com/showthread.php?p=744783&highlight=rudder delamination

mz4wheeler · Apr 7, 2015

It is guaranteed to be waterlogged.

I'd cut out the fiberglass from the bottom part of the rudder and let it drain. To do this, you may have to drill a few holes at the top so air can enter as the water drains. It may take a long time. You may be able to inject air at the top via a compressor or shop vac to pressurize and force the water out. After, grind out the cracks in the middle. Find the hollow sections by tapping with a hammer and inject epoxy.

I had to do all of this [grin].

RTB · Apr 7, 2015

Jim Legere said:
When I had the pre-purchase survey done on my H37C (way back in 2001) the surveyor noticed similar horizontal cracks on my rudder. Long story short, it became a point of contention in the sale and we ended up factoring the cost of a new rudder into the price. Foss Foam in Florida still makes rudders to order for our old Cherubini Hunters. I seem to recall a new rudder was around $1500 back then. Foss Foam's website has some good pictures of how the rudders are made:
http://newrudders.com/?page_id=12
If the cracks are really worrisome, you could always remove the rudder and split it with a zip cut wheel on a grinder, inspect the SS frame, make any repairs, and epoxy everything back together. A big job but doable. I kept my old rudder, just in case I ever wanted to do this but I have yet to tackle it...:lame:

I give a thumbs up to Foss Foam. We put one on 2 1/2 years ago. I think the price is about $1900.00 now. Worth it in my opinion if sailing offshore much like we do.

The yard that did the work didn't bother with removing the mold release on the new rudder, plus didn't bother to barrier coat it. It has been the curse of many divers over the past 2 years, since it was basically bare gelcoat by the time we got to New Orleans. Apparently no damage though, since we just hauled out to do a bottom job. The rudder now has 3 coats of 2000E, plus bottom paint. Ready to go cruising again.

Ralph
http://www.sailblogs.com/member/brogdon/

rardiH36 · Apr 7, 2015

Hello RTB:

Although your RTB user name has rung a bell with me, I really haven't recalled you very much. So great that you have again "revealed" yourself as a participating Cherubini H36 owner!

Obviously I am one too.

There are too few of us that contribute to the particulars of our really well-built and good-performing 36' 1980-82 boats. Probably because not all that many boats were manufactured by Hunter. And with each passing year, fewer remain.

Hope that you continue to weigh in from time-to-time. It's not necessary that any of us know the exact answers to any posts/questions. Just replying with insights or experiences or questions can often trigger a different thought process to the best solution.

Jim Legere · Apr 8, 2015

Most barrier coats are epoxy based. Epoxy's adhesive properties are pretty good. My feeling is that clean (free from antifouling) barrier coat that was properly applied and is well bonded to the gelcoat would be a suitable substrate for further epoxy based products such as epoxy putty or fairing compound...you could contact you epoxy manufacturer's technical support to be sure.

RTB · Apr 8, 2015

rardiH36 said:
Hello RTB:

Although your RTB user name has rung a bell with me, I really haven't recalled you very much. So great that you have again "revealed" yourself as a participating Cherubini H36 owner!

Obviously I am one too.

There are too few of us that contribute to the particulars of our really well-built and good-performing 36' 1980-82 boats. Probably because not all that many boats were manufactured by Hunter. And with each passing year, fewer remain.

Hope that you continue to weigh in from time-to-time. It's not necessary that any of us know the exact answers to any posts/questions. Just replying with insights or experiences or questions can often trigger a different thought process to the best solution.

Well, I do check here from time to time, and enjoy offering my thoughts if it's a topic I can help with, so thanks for the welcome.

Actually, we have run across a fair number of 80-82 H-36's in our travels. I guess 8-10, which actually surprised me. There is one here at Cove Harbor in Rockport, besides mine. I also recall one anchored off Gulfport, Florida. It was a derelict with no engine, but a couple living aboard. Also, met up with some fellow Texans in Boot Key Harbor last year, aboard Moonlight Sue - http://www.sailblogs.com/member/moonlightsue/?xjMsgID=319464

Our Hunter has been great so far. 5000 miles in the past 2 1/2 years. We have lived aboard since Aug 2012.

My thoughts for the OP.....these boats are getting old, but have some good years left in them if you take care of the boat. A lost rudder can easily require abandonment if offshore in bad weather. Do you really want to risk it? Keep everything good below the waterline - new, or at least closely inspect thru-hulls and hoses. If you're good below, not much chance of sinking. My standing rigging is old, but still passes inspection - no candystriping or meathooks. Still, new rigging may be on the list in the near future. Just my 2 cents.

Ralph
http://www.sailblogs.com/member/brogdon/

mz4wheeler · Apr 8, 2015

Rebuilding A Foam Cored Rudder Parts 1,2,3,4,5

https://www.youtube.com/playlist?list=PLV97GZkHhpHMfaW24ZBR-xitL-TN2si9A

Rudder cracks - '81 Cherubini Hunter 36

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