Rudder repair

Hi.

The rudders of my newly acquired HC 21SE seem to need some attention. What would you suggest to fix this?

Rudder 1

Rudder 2 - Deleted

Rudder 3

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Hobie Cat 21SE #376

That's easy. 1st, unbolt the rudders. 2nd, wash them thoroughly with unscented, liquid dish soap and water and add a good amount (1/2 cup?) of TSP (trisodium phosphate) in the soapy water in order to get rid of anything like mold release, oils and grease.
3rd, roughen up the areas real good with like 80 or 100 grit so the epoxy will grab. The split needs to be sanded inside and opened up just a hair so you can get laminating resin (thinner) inside to glue the halves back together.

wipe with acetone or paint preparation solvent to do a last clean.

use a good epoxy (West or ProSet are very good) and some thickener like colloidal silica to make the epoxy mix like a peanut butter consistency. I added white pigment to the mix, but it doesn't match perfectly. Looks better than raw epoxy but the rudders still need good paint now. Sculpt it in like clay; if you can get some thick Mylar from an art supply store you can use this like a flat panel on each side, sandwiching the repair. Epoxy won't stick to mylar, so you end up with a flat, smooth surface. Much easier to sand/shape after. You'll likely do a couple rounds of this.

The cracked rudder isn't too bad either, but you'll need to 1) somehow clean and sand just inside the edge so the epoxy will grab and 2) widen the crack just a hair so you can get the mixed epoxy inside. The colloidal silica can be used to make the resin a little thicker so it's not so runny and a little more controllable.

You can also do the repair with matching gel coat and the like, but I have no experience with that. Or rather, very little experience with gelcoat.

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ChuckC
H21SE- 408

Those look like custom/home made rudders and part of the problem looks to be that the rudder is not meshing well with the lower casting where it seats at the very front of the casting when locked down. This is causing the casting to wear into the rudder stock.

First I would try to figure out what the rudder construction is. It certainly looks like fiberglass, most likely over a wooden core. Assuming that’s the case, I would recommend using some 80 grit sand paper to remove material from the rudder stock where it seats into the lower casting (the area where the wear is occurring). Remove material until the rudder easily fits into the casting. Then scuff sand the entire surrounding area and apply a few layers of fiberglass saturated with epoxy resin to reinforce and seal the rudder. Sand the area smooth and then paint the rudder with spray paint to cover the repair.

sm

Interesting, it would not surprise me if the rudder is custom since everything else on this boat seem to be. Does anyone have a picture of a stock HC 21SE rudder? What is that made of? What are the measurements of a stock rudder? These look like fibreglass over wood but I will check to make sure.

I will try to follow your good instructions on the repair. Obviously there is a rubbing problem that needs to be sorted first.

Thanks!

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Hobie Cat 21SE #376

The outline of your rudders looks like it was based off of a stock hobie rudder. I’m sure if you google Hobie Rudder, you will get plenty of results to show you what one looks like. The 21SC uses the same rudder blades as almost all the other boats (Wave, 14, 16, 17, 18, etc). They are more or less universal between the different models, so easy to come by. The materials vary depending on the quality of blade you are looking for. The higher end versions are fiberglass or carbon fiber over foam core. The less expensive versions are molded plastic. My guess is your boat had molded plastic rudders, one broke, and the previous owner decided to use the remaining “good” rudder as a template to build a new set.

If your existing rudders sail well, I would keep using them. Just fix the forward edge so they don’t rub anymore and seal them up.

sm

are you flexing the rudder in the second picture, like is it a short video? If so, that isn't good.

SRM is right on the 21SC-same rudders as the 18, so a lot should be around. If you do buy something, I'd sure try to find fiberglass for ease of repair. If these are wood core, then they're saturated; may need to ventilate and bake them at a low temperature, but thats getting into a lot of work when replacements are easily had.

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ChuckC
H21SE- 408

If I had just about any other cat than the 21SE it seems that rudders can be found easily. I have never sailed this boat (or anything else for that matter ) but the previous owner said it sailed well so to begin with I'll try to fix the rubbing issue, fill the crack, seal them up and try them out.

There is no flex in the rudders. I have no idea why that picture ended up being a video. I have removed it.

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Hobie Cat 21SE #376

there are options for rudders, but just fix stuff enough to get on the water safely, then prioritize your work. Likely your priorities may change based on what you discover. I know mine did a little.

How old are the shrouds? I replaced mine right away not being sure of the history of them. You don't want to drop the mast, because thats the one irreplaceable part that you cannot find. Rudders, I THINK you can still use the H21SC or H18, even though they're slightly shorter, or make your own.

Good luck.

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ChuckC
H21SE- 408

Thanks. You are right, of course. I have quite a few things to check and shrouds are important for sure. They have not been replaced in the last 7 years or more. Also, the boat has not been used much lately. I would like to replace them with synthetic rigging but I haven't really looked into that yet.

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Hobie Cat 21SE #376

If you are thinking of fresh rigging, look at the shroud anchors, they may well need replacing.
(they go through the lip of the hulls, they can bend inside where you cannot see the damage).
Lots of articles on this on the Forum.
Good luck

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2015 H16, with spin,
SOLD 1989 Hobie SX18 Sail # 1947 "In Theory..."
'Only two things are infinite, the universe, and human stupidity. But I'm not sure about the former.'

OK! Thanks for pointing that out.

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Hobie Cat 21SE #376