Rudder Reinforcement After Rebuild

[rognvald]

I am rebuilding my rudder to repair areas of delamination caused by heat stress while on the hard in Florida. I have sanded the surface of the rudder to the original fiberglass and will re-core and glass the repaired areas that were damaged. Is there a benefit to reinforcing the leading and aft edge of the rudder with carbon fiber tape for strength followed by a thin layer of fiberglass on the entire rudder before sealing it with a barrier coat, primer and bottom paint? Any first-hand experience will be greatly appreciated.

[robert sailor]

Not sure how yours is/was built but I liked to wrap mine because most of them are built in 2 half's and I have seen them fail at the joint.

[rognvald]

Originally Posted by robert sailor

Not sure how yours is/was built but I liked to wrap mine because most of them are built in 2 half's and I have seen them fail at the joint.

Hi, Robert,
My rudder is built with two halves on a stainless shaft and cage with a foam core. I could not detect any fiberglass on the top and bottom of the rudder--only epoxy sealing the halves together. Thanks

[HappyMdRSailor]

Originally Posted by rognvald

I am rebuilding my rudder to repair areas of delamination caused by heat stress while on the hard in Florida. I have sanded the surface of the rudder to the original fiberglass and will re-core and glass the repaired areas that were damaged. Is there a benefit to reinforcing the leading and aft edge of the rudder with carbon fiber tape for strength followed by a thin layer of fiberglass on the entire rudder before sealing it with a barrier coat, primer and bottom paint? Any first-hand experience will be greatly appreciated.

I plan to do exactly as you described on a rudder rebuild... Sooooooo.... Us being the smart guys that we are... Are probably on the right path!

Until the resident resin head chimes in and points out how flawed our logic is... I'm OK with public ridicule though....

[rognvald]

Thanks Robert Sailor and HappyMdRsailor for your replies. It appears that this is a very difficult and esoteric question that even the most knowledgeable on this Forum are unable to answer. Good luck with your projects. I'll keep you posted on my continuing research as I continue my rebuild.

[HappyMdRSailor]

Originally Posted by rognvald

Thanks Robert Sailor and HappyMdRsailor for your replies. It appears that this is a very difficult and esoteric question that even the most knowledgeable on this Forum are unable to answer. Good luck with your projects. I'll keep you posted on my continuing research as I continue my rebuild.

You bet... I'll post pics when I get to the project for sure... Mine is a bit more complex rebuild of a missing bottom 1/3... Lower 1/3 blank/form is shaped... Plan to:

1. layup lower 1/3
2. foam fill above
3. assemble 2 pc
4. wrap entire assy in 2 layers bi-ax
5. cut window in rudder side at joint
6. remove some foam and create a "fingered interface"
7. pour another load of foam

Now our procedures align.....

8. Tape leading and trailing edges in carbon
9. wrap entire assy in glass...

10. make pretty

Now we wait for correction... admonishment... or hand holding

[Cheechako]

One consideration: should you refoam the interior? Maybe fill with a casting resin and microballons or something like that that wont absorb water so well as expanding foam. Weight issue? If you think about it.. how much does resin and filler weigh in the water? Less than it does on the hard anyway... I've seen many a rudder filled with water... most with no apparant damage, cracks leaks. It is my belief that many leak water in around where the shaft exits the rudder. How to stop that? I chose to fill mine with resin.

[Nicholson58]

Originally Posted by HappyMdRSailor

I plan to do exactly as you described on a rudder rebuild... Sooooooo.... Us being the smart guys that we are... Are probably on the right path!

Until the resident resin head chimes in and points out how flawed our logic is... I'm OK with public ridicule though....

Did I hear some one call? You can't loose by adding material at what might be a weak joint as noted above. As long as you are doing only an area patch what you suggest is good. I assume from your post that the rudder is probably a cantalevered spade. They give great control especially in tight spots but they sure do stick out when it comes to impacting stuff.

If you get to a replacement and want to do it yourself, I have posted my how to in other threads. I have some pictures here Member Galleries - Cruisers & Sailing Photo Gallery

I prefer US Composites 635 thin epoxy and I use their micro-balloons as filler instead of foam. Microballoons form a syntactic foam with epoxy and have a very high strength especially cast in with a skin. It is also totally waterproof - forever. Fiberglass , Epoxy , Composites, Carbon Fiber - U.S. Composites, Inc. Their stuff us also the lowest price most times.

Send me a PM if you want details.

[HappyMdRSailor]

Originally Posted by Cheechako

One consideration: should you refoam the interior? Maybe fill with a casting resin and microballons or something like that that wont absorb water so well as expanding foam. Weight issue? If you think about it.. how much does resin and filler weigh in the water? Less than it does on the hard anyway... I've seen many a rudder filled with water... most with no apparant damage, cracks leaks. It is my belief that many leak water in around where the shaft exits the rudder. How to stop that? I chose to fill mine with resin.

Originally Posted by Nicholson58

Did I hear some one call? You can't loose by adding material at what might be a weak joint as noted above. As long as you are doing only an area patch what you suggest is good. I assume from your post that the rudder is probably a cantalevered spade. They give great control especially in tight spots but they sure do stick out when it comes to impacting stuff.

If you get to a replacement and want to do it yourself, I have posted my how to in other threads. I have some pictures here Member Galleries - Cruisers & Sailing Photo Gallery

I prefer US Composites 635 thin epoxy and I use their micro-balloons as filler instead of foam. Microballoons form a syntactic foam with epoxy and have a very high strength especially cast in with a skin. It is also totally waterproof - forever. Fiberglass , Epoxy , Composites, Carbon Fiber - U.S. Composites, Inc. Their stuff us also the lowest price most times.

Send me a PM if you want details.

*** OFFICIAL THREAD HIJACK NOTIFICATION***

Great thought (both of you) on using epoxy/micro... If I was to build from scratch, I would definitely go this way... Top 2/3rds intact, and zero sign of water intrusion... Still might go this was as filler interface would be definitely stronger...

Nice pics Nicholson58... I definitely agree with you on US... I use others including JD too... But US has the goods at the lowest prices for sure!

[robert sailor]

All good info. On my last rudder I drilled holes in the bottom and out came water, quite a bit. I made a template of the foil shape and drilled 1" holes and inspected the shaft connections and poured resin in, let it set up and then patched that hole and worked up the rudder drilling holes, inspecting and filling with resin. By the time I got to the top I had used 3 quarts of resin that filled voids. Wrapped it after I was finished. In Canada its not uncommon for rudders that are wet to freeze when they are on the hard and make a tiny split between the halves and they can literally peel off when loaded, like in a broach. Not common but it has happened.

[Nicholson58]

Originally Posted by robert sailor

All good info. On my last rudder I drilled holes in the bottom and out came water, quite a bit. I made a template of the foil shape and drilled 1" holes and inspected the shaft connections and poured resin in, let it set up and then patched that hole and worked up the rudder drilling holes, inspecting and filling with resin. By the time I got to the top I had used 3 quarts of resin that filled voids. Wrapped it after I was finished. In Canada its not uncommon for rudders that are wet to freeze when they are on the hard and make a tiny split between the halves and they can literally peel off when loaded, like in a broach. Not common but it has happened.

The drill & drain is a common quickie fix. The problem is that it deludes one into thinking the water has been removed. Urethane closed cell foam cast in place and faired is a standard construction. The foam is closed cell and repels water well for short exposures. If you look up the properties though you will note that it has a non-zero permeability. Over time it will become waterlogged just as a tree trunk will. Once water has made its way in, freeze/thaw will break the cells, opening the foam to more ingress. Add to this the mechanical flexing contributing to mechanical fracturing and the entire rudder will become a piece of florist's foam. Drilling a hole will let out a few pools of liquid from the most totally damaged foam but you only delay the inevitable.

The core in my own rudder was diminished to only about 30% of its original volume and the hollow interior was wads of fuzzy black mold. The skin was mushy de-laminated crud. I consider foam a poor filler for an object that is intended to be immersed 100% of the time. For this reason, I chose the 635 and ballooons. 3 gallons of 635 thin mixed with a drywall mixer and 10 to 12 gallons of balloons makes 15 gallons of syntactic foam. The 635 is very slow cure (days) so no heat build-up problems even in my 6" thick pour. The compressive strength is 3000 psi and the skin will bond 100% to the core so the resulting strength is massively greater than foam core. There was some question as to the density of the syntactic foam. It is very light. Based on my mix ratio, density is about 22 to 25 #/cubic ft. Definitely greater than new foam but way less than water-soaked foam.

One method of repair short of total re-build would be to open windows in the rudder suitable for digging out all of the foam. Clean and scrape thoroughly and solvent wash. Make sure it is baked dry (in the sun) and pour in the epoxy-balloons filler. Repair the windows - done. This assumes the skin is in good shape.

The recipe I noted will yield a mix that is nearly dry to the touch. Trust me - it will wet the contact area to the rudder's skin and give you a very strong bond. The dry mix is easy to handle since it won't stick to you with a casual touch.

[Cheechako]

I opened a rectangular window about 75-80% of the rudder on one side only. I was able to remove all the mushy foam, the glass was solid as a rock. I was able to let it dry thoroughly and inspect the welds on the tabs. Then I tapered/faired the glass and put the window panel back on the rudder. Cored two 3/4" holes on the top of the rudder and filled 'er up with epoxy slurry. All this was done with the rudder in the boat.

[rognvald]

Nicholson58,
Your suggestion of U.S. Composites was excellent. I have spoken with Steve in their technical support department twice and he has been very helpful and informative. Here's the link again for anyone interested:
www.uscomposites.com/‎ Good luck and good sailing.

[HappyMdRSailor]

They do rock with the customer service and price!

Sent from my SCH-I535 using Cruisers Sailing Forum mobile app

[Nicholson58]

Originally Posted by rognvald

Nicholson58,
Your suggestion of U.S. Composites was excellent. I have spoken with Steve in their technical support department twice and he has been very helpful and informative. Here's the link again for anyone interested:
www.uscomposites.com/‎ Good luck and good sailing.

I'm glad to help. Did you find my photos? I posted a mess on the forum. Member Galleries - Cruisers & Sailing Photo Gallery