Rudder Question

[Bad Obsession]

On the Compac 23 the previous owner told me that the after-market rudder started to crack a while back. He had someone "weld" the plastic at the back of the rudder to repair it. He then saw it start to crack at another location the other day behind where the weld was. He told me that he felt that it was caused from being out in the sun. He closed the new crack with 5200. If he had kept the boat he stated that he was going to fiberglass over it plastic.

The original crack was on the trailing edge of the rudder. The rudder is made out of a plastic material so that is why the PO had it welded back. The new crack that the PO noticed was behind the area that was welded.

The good thing is that I do have a spare rudder. It is the original Compac Rudder. The difference is that it is not foiled and it is just a flat aluminum blade (the boat is supposed to sail much better with the after-market rudder).

The after market rudders run about $450.

Would putting a layer of fiberglass over the plastic be a viable fix? Any other suggestions on how to fix this? If so, how would be the best way to do this (prep and then resin and cloth)?

 

[svchickadee]

Who is the manufacturer of the replacement rudder and what is the year of manufacture? I have an aftermarket rudder on my ODay 25 and am wondering if the rudders were made by the same company.

Thanks....

 

[victorhoisington]

Not sure about the Compac aftermarket rudders., I had a Hunter 25 which had developed severe cracks all along one side and across the top on the other due to how it was exposed to the sun in winter/Summer. The cracks are a product of the outgassing done by the foam in the rudder and are not structural. They do however allow water to penetrate and so over time the rudder is weakened.

When I got my Hunter, I did a "wrap" of the rudder in fiberglass. Admittedly, I didn't know much and didn't have the advantage of this site at the time to learn from. However, I sanded and faired the existing rudder to bare fiberglass, removing most of the gelcoat, wrapped the rudder in fiberglass cloth and epoxy and then finished it with bottom paint.

The job lasted for several years before the cracks came back and so accomplished my goal. However, here are a few lessons learned:

1. I should have opened the rudder up and repaired/replaced the foam to ensure it was completely dry and in good shape and also couldhave inspected the rudder stock for corrosion
2. 2 or 3 layers of fiberglass would have been better than 1 but, overall it didn't really matter. Since I hadn't removed the cause of the cracks (foam) it was inevitable that they would return.
3. Either recoat the fiberglass with gelcoat or ensure a good 2 part epoxy barrier coat is applied before bottom paint. If I had done this, I might have gotten another season or two before the cracks reappeared and it would have prevented any issues with blisters. However since the fiberglass was completely covered in bottom paint, there were no issues with UV degradation like you would see with exposed Fiberglass.

The job is not particularly hard but as I was learning I wasn't sure. Finally my wife just said do it - quit thinking, we did the job that night and it worked. I got a few more years with the rudder and didn't spend a lot of $$.

Good luck

Victor

 

[DAVA390]

Well, I don`t know enough to help you on this but i would think there is going to be load demanding of photo`s!! Maybe they would help people figure something out.

 

[Bad Obsession]

Hrm.....Photos are an issue because the cracks are gone. Previous owner filled them with 5200 (Devil's Glue).

I am not really good at finish glass work. The rudder is supposedly made of plastic and not fiberglass.

The Previous owner thought that it had something to do with sun exposure of the rudder to the sun. It is a kick-up rudder that is usually left up when the boat is in the water. The back of the rudder was "welded" three years ago.

I am guessing that I could clean the rudder off and then sand it some lightly. Then cover with epoxy resin and cloth. Sand the finished product to smooth. Repeat the process. Then paint with epoxy paint.

Does this sound right?

 

[victorhoisington]

sanding before doing any glass work is usually recommended to be with 80 grit to ensure good adhesion with the base material. since we are completely encasing the rudder in glass and resin, you should be fine at 80 grit.

I wasn't good at finishing either, you develop a knack for it after a while. Get a reasonably good random orbit sander and have fun. Wear a mask for dust but otherwise just have fun. The nice thing about green resin is it sands much easier than fully cured resin, and if you go too far just add more glass/resin and your fine.

Good luck

 

[Crazy Dave Condon]

Most often rudders with foam fill which by the way is used to keep the weight of the rudder down, will get wet if there is a crack. If that ever happens, so often people will repair the rudder without thinking of letting the rudder dry out first or should I say the foam. Before any repair, I use to drill a couple of holes in the bottom of the rudders and would let them stand up so the water would seep out to let them dry. Then I repaired the rudders.

Another source of splitting rudders can be from heat build up for example a rudder painted with dark anti fouling paint left up out of the water in sunlight is another source. So if one is doing that all the time raising the rudder out of the water when not in use, then remove the anit fouling paint.

 

[finding41]

Here is a video of how to repair it. https://i1.ytimg.com/vi/MRXNnFx7DBQ/mqdefault.jpg
It is for a foam core fibreglass rudder but a lot of it will apply to your rudder. IE the foam inside and how to deal with that.
You can always make a mould from it and make a new one out of fibreglass. (That will make you better at finish fibreglass .)
Note; I have heard of people drilling a hole in the bottom of there rudder after fall haul out and patching it in the spring to allow it to drain of water. I don't know if that is a viable option for a plastic rudder though.

 

[Brian S]

So, I believe that the newer, upgraded foil rudder blades on Com-Pacs (and Ruddercraft rudders) are UHDPE, ultra high density polyethylene, just like King Starboard is. (Older Com-Pacs use a flat plate aluminum blade.) This is borne out by the assertion that the blade was previously "welded," which is where you melt a PE rod into the substrate with a heat gun. I am familiar with that process from repairing run of the mill polyethylene as used to make rotomolded plastic kayaks. Or milk jugs.

I do know that PE is not all that UV resistant, though I think that UHDPE, and also Dyneema and Spectra lines are more UV resistant, either by construction or coating. I have seen milk jugs, crappy single braid PE rope, and kayaks bleach and get brittle in the sun, so I would expect a similar effect on the plastic rudder blades.

If all of this is true, then it's probably a waste to try and weld cracks due to UV exposure, because you're welding in new material to brittle, dry, degraded plastic. I suppose 5200 is one attempt to fix it.

I do know that regular PE is very waxy, and very little sticks to it well. Lexel brand caulk is used to glue foam bulkheads inside plastic kayaks. Dyneema is a very slippery fiber. So, I expect that plastic rudder blades (and Starboard) are very similar, and not much would stick to it. So, I don't know how successful you'd be in wrapping the rudder with fiberglass and epoxy. I think if you tried to build up enough laminate to be structural, it would be too thick for the headstock, and very heavy to boot.

I think I'd cut my losses and buy a new blade from Hutchins (Com-Pac) or maybe Ruddercraft, if Ruddercraft is supplying Hutchins.

From what I saw on my friend's Com-Pac 23 a few weeks ago, that blade is definitely NOT a fiberglass and foam sandwich as stated above by a few folks. He once broke a blade off his outboard prop accidentally grinding the trailing edge of the rudder. I could see through the chunk that it's solid plastic. He's not proud of that chunk, but it allowed him to buy a Micky Mouse ear bladed high thrust prop, which he needed.

 

[MrBill_FLL]

we need pics!