How To Repair a Rudder

Rudders damage easily. Although they work similar to a keel, they aren’t nearly as tough. If you dry sail, the edges can accumulate nicks and dings in the fiberglass from loading and unloading. The rudders of some sailboats can hit the outboard motor’s propeller if you’re not careful. Add in accidental groundings, storage damage, and stress cracks and it doesn’t take much time in water to make the wooden core swell and damage the rudder even more. Without repairs, a weakened rudder can even break into pieces under stress. It pays to protect your rudder.

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Example of a damaged upper trailing edge
A badly damaged upper trailing edge. Some chips are completely through the fiberglass skin.
Example of a crack caused by a swollen core
A crack caused by a swollen core lets water in quickly and out slowly
BEFORE - lower trailing edge
A worn lower leading edge. The wood core is exposed and delaminating.

If your rudder is showing any bare wood, has deep nicks in the edges, or has swelled and cracked the fiberglass at the edges, you should repair it while you still can. All of these kinds of damage are easily repairable by the do-it-yourselfer for a small fraction of the cost of a new rudder.

It’s just like doing auto body work

If you’ve ever done any auto body work, you know the goal is to build up and restore a smooth shape to damaged surfaces. It’s the same with your rudder but the finish quality doesn’t have to be as perfect.

Follow these steps to make your rudder smooth and watertight again:

1. Start with a 4″ handheld grinder or similar power tool to remove all of the rough and damaged fiberglass down to solid material.  Also remove all damaged wood core material. This might seem overly aggressive but the repair won’t last unless it’s built on a solid foundation and a grinder will get you there fast. By removing the rudder’s skin, it will dry out faster.

2. Let the wooden core dry out as much as possible. You don’t want to trap moisture in the core where it will dry rot. If you lay up your sailboat for the off-season, that’s a good time to dry out your rudder. Finish the repair before the start of the next sailing season.

3. After the core has dried thoroughly, use a random orbital or similar power sander to feather the ground edges back a couple of inches all around and to remove any paint so that an epoxy patch will stick properly to the original fiberglass.

Sanding the lower edges before fairing
Sanding the lower edges before fairing

4. Mix some thickened West System or an equivalent epoxy and build up the ground and sanded areas to their original shape. Colloidal silica is a good thickener for this application.

5. With a power sander or sanding block, carefully smooth the patched areas to match the surrounding surfaces and edges.

Upper trailing edge built up with epoxy
Upper trailing edge built up with epoxy
Lower leading edge built up with epoxy
Lower leading edge built up with epoxy
Lower trailing edge built up with epoxy
Lower trailing edge built up with epoxy

7. Apply a barrier coat of one-part polyurethane  or two-part (preferred) epoxy paint over the repaired areas.

Repaired edges with new barrier coat paint
Repaired edges with new barrier coat paint

6. Fill small cracks above the water line with Capt. Tolley’s Creeping  Crack Cure.

Top rear crack sealed and painted
Top rear crack sealed and painted

7. Last, re-apply ablative paint or a polyurethane topcoat to match the rest of the rudder or hull. If you keep your sailboat in the water, ablative paint can minimize algae growth. If you dry sail or remove your rudder when you’re not sailing, ablative paint gives no benefit and will just transfer to everywhere you don’t want it. I reapplied ablative paint to this rudder but I sanded it off a year later and applied a gloss white polyurethane when Summer Dance got a different color bottom paint job.

8.  Now is a good time to remove, clean, polish, and rebed all of the rudder hardware with butyl tape. If the tiller bushings are worn, read How to Replace Worn Tiller Bushings.

Now that you have a restored and sealed rudder, take good care of it and it will take good care of you!

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21 Comments Add yours

  1. m4n4ger says:

    Hello from the UK! The rudder on my Jaguar 22 is the pivoted type to cope with grounding when the keel is lifted. It’s made from dense dark wood (mahogany I think) and it weighs a TON! It worries me having all that weight hanging off the f/g transom plus the outboard – it flexes the hull… I’ve seen some of the Gucci lightweight racing replacements available in the States for mega-bucks, but I wondered if you’d ever considered making a replacement lightweight rudder $tingy-style from (say) stainless or aluminum frame,with glass fibre coverng over foam, or similar? It would be a fascinating project!

    Keep up the good work!

    Mike (Tamariu) Jag 22

    1. Hi, Mike

      Your description makes me wonder if a previous owner made your kick-up rudder blade himself. No factory C-22 rudder that I’ve ever heard of was made of hardwood. I can’t imagine why the UK builder would go to that expense and being a licensee of Catalina Yachts, they would be legally bound to stick to the factory designs, materials, and methods.

      As a matter of fact, I do have tentative plans to make a balanced rudder similar to what you describe or possibly of solid, lightweight cedar, so stay tuned!

      1. m4n4ger says:

        Sounds good – I’ll keep watching!

  2. Richie says:

    Great informative article. Enjoy all your postings, have learned a lot.

  3. Jeff Powell says:

    Has anyone ever made a new rudder solely out of wood?

    1. Hi, Jeff

      I’ve seen one fella’s rudder that he made out of mahogany and it weighed a ton. Others have attempted to make balanced rudders to replace the stock one. Rudder Craft makes high performance replacement rudders but they’re pricey and they also aren’t class legal for racing. Building a balanced rudder with conventional techniques is on my to-do list so you might see it here someday!

      1. Jeff Powell says:

        Well, I am a novice sailer at best. I won’t be racing, so a little extra weight won’t hurt much. From the looks of the rudder I have, it is has a wooden core in it. I just aquired the sailboat with some restoration needed. The rudders bottom has the fiberglass rubbed off. I have access to some cedar planks the same size as current rudder, so I was thinking of a nice winter project. Boat stays trailered when not in use.

      2. Cedar would be strong, lightweight, and rot resistant. Go for it and send me some pictures when you’re finished and I’ll add them to the Reader’s Gallery.

  4. Ed says:

    Here is a link that I hope will take you to my pictures of the Sage 17’s rudder system in the Google ‘Photos’ cloud:
    (I prepared some comments before I searched for the photos and the text disappeared when I returned…maybe they got posted…)

    I really appreciated and look forward to the clear and concise project posts!


    1. Very nice. Can you describe how it works here? It looks like when you raise the tiller handle, the rod rotates the blade up and the bungee holds it in position. What did you make the blade out of, mahogany?

      1. Ed says:

        I think you understand it better than I do…and as described here: (see tab on stern & rudder features)

        As I recall, the Sage rep said it took some experimentation to get the balance just right for the length of and attachment points for the rod on blade and tiller. You will see the rudder is outsourced to another manufacturer…I wonder if they have branched out to other boats?! The blade is mahogany, they note…

        It doesn’t look to like it would be that hard to replicated, if you have the capability to fabricate/locate stainless parts.
        I’ll be interested to read how you’d do it, when you’ve replicated a similar designed for your boat!


      2. Ah, I understand now with your link to Sage Marine. I thought you made the rudder yourself.

        I was planning to make a balanced, fixed-style rudder but now after seeing how yours is made, I just might make a kick-up rudder instead that will lock up for trailering!

        Thanks, Ed

      3. Ed says:

        You bet. Just a little payback for all your great info. If I hear back that J O Boatworks will customize the design to meet other boats, I’ll let you know!

    2. Jeff Powell says:

      Well, we are almost finished with the rudder out of cedar. Instead of one solid piece we had to use 3 pieces thick of varying lengths that we planed and glued together then molded and sanded then applied more that 10 coats of marine varnish. Hardware is basically all we have left. Only thing, we we got involved and forgot to take very many pictures until the almost the finished product…sorry I can’t figure out how to post a picture here…

      1. Sounds fun, Jeff. Take the best pictures you can and enter the 2017 Stingy Sailor DIY Project Contest coming soon!

  5. Edward A. Bachmann says:

    If you want to have a balanced kick-up rudder like JO Woodworking fabricates for the Sage, contact him from his website.

    We emailed numerous times to confirm he could get the system to work for my setup and pricing seems fair! I am hoping my tax refund can pay for one for my Venture 21!

    Happy sailing in 2017!

  6. Christian Clark says:

    Hey Stingy, another helpful post, thank you. I had my rudder snap off sailing day before yesterday thanks to rusted hardware.. Anyway you mentioned that you ended up sanding off the anti fouling paint, and as you know it is quite pricey and sold in quarts (way more than needed for rudder bottom half) so would you say that using it is a little overkill? Do you think the growth would be much more uncontrollable without using it? I’d rather save the $50 and skip the anti fouling paint if it’s not a massive difference in growth/cleaning.

    1. Hi, Christian

      If you leave your rudder in the water all the time, then antifoul paint will make it easier to keep clean of marine growth. If you have a kick-up rudder and retract it when not sailing or, like I do, take the standard rudder off unless you’re sailing, then the extra paint is overkill. I connect my tiller with a quick release pin so it takes less than a minute to mount and dismount. This way, I’m able to keep my rudder clean and drag-free. I just wipe it down occasionally. It also minimizes the amount of water that can penetrate into the core through pintle holes and cracks and weaken it, which can result in catastrophic failure like you’ve experienced.

      If your rudder wasn’t badly softened from water intrusion, then you should carefully question why it broke. If you weren’t in a dangerously rough sea state but had extreme, prolonged weather helm in normal conditions, then you might not have balanced the sail trim properly. When properly trimmed, you should be able to steer with minimal effort in all but the worst conditions.

      Hope that helps,

  7. KT Kuehl says:

    Hi there, I have a C-lark with an all-wood rudder that is starting to crack around the gudgeon (I think that is the correct term). The cracks are starting at the top and running parallel to the long axis of the rudder. I haven’t been successful finding an appropriate used replacement, so am thinking about trying to fix this one. With a few of the cracks full width (not length) at the top is it worth trying to re-work this one, or would it be better to start fresh using this one as a blue print? If so, any resources you could recommend on materials and considerations? Thanks!

    1. Hi, KT

      I very nearly got a derelict C-Lark for free so I know what a fun little boat that is. I’m a little confused about the cracks you describe as running along the long axis of the rudder but also full width. At any rate, I’m a big proponent of fixing anything that can be fixed. Your rudder might take some creative joinery to make it solid again but you have nothing to lose by trying, right? Depending on the extent of the cracks, I would either use waterproof glue and clamp the cracks or cut the rudder along the cracks, square the pieces up on a joiner, and then glue and clamp it together again, possibly using dowels or biscuits for additional strength.

      If the damage is too extensive to repair, there are lots of materials that make a good rudder. Probably the easiest is either a solid piece of HDPE, which would be impervious to moisture and should last forever but require a lot of hand shaping or clear grain cedar with a fiberglass shell, which would be strong and lightweight and easier to fabricate.

      It would make a great DIY project, so keep us updated on your progress,

      1. KT Kuehl says:

        Thanks, I think I am going to give a go at making a new rudder with cedar and fiberglass as you suggested. I have a friend with some skills who is going to lend a hand, but I will take photos and post our progress. Thanks!

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