Perfect sail trim results in maximum forward speed, minimum heel, and a neutral helm. In other words, the sails are balanced between the headsail and the mainsail and the tiller requires little to no input to hold the sailboat’s heading. But we all know that perfection is elusive and it’s a moving target. Wind and water change and sometimes we can’t or don’t want to adjust the sail trim accordingly. That can mean that the sails are out of balance and you have to apply more force to the tiller to hold your course, also called weather helm (windward) or lee helm (leeward).
Weather helm often occurs when you have too much mainsail aloft or too little sail twist and the sailboat wants to turn into the wind. If you don’t counter that with the tiller, the sailboat could round up unexpectedly in a puff. The best way to prevent this is to reef the mainsail to reduce the amount of it exposed to the wind. If your sailboat has one, you can also ease the boom vang to allow the mainsail to twist at the top and spill some air, also called vang sheeting. You can read about how to set up a reefing line in Single Line Jiffy Reefing Made Easy. Either of these methods will also reduce the amount of weather helm you feel at the tiller. But if you get caught in conditions when it’s unsafe to reef, the conditions are only temporary and don’t warrant reefing, or you just don’t want to reef such as when racing, then the excess weather helm can sometimes be acceptable when handled with extra caution.
However, if you have a C-22 or similar sailboat with an angled (unbalanced) rudder, you can reduce weather helm overall with a simple modification to your rudder’s angle. This hack works because back-swept rudders are designed to provide easy control at slower speeds and to not be too sensitive. The portion of the rudder in the water is angled aft slightly. On a C-22, this is about 2″ at the rudder tip. This places the rudder’s wet surfaces aft of the rudder’s pivot axis (pintles) exaggerating its lack of balance. A rudder is considered to be balanced when a portion of its wet surface area is located forward of the rudder’s axis to counteract the force of the water on the portion aft of the axis.
This modification consists of placing a spacer between the upper rudder gudgeon and the transom.
This angles the top of the rudder slightly aft and conversely angles the bottom forward edge of the rudder into alignment with the transom and bottom pintle, effectively eliminating the back sweep and improving its balance. This gives the tiller more leverage over the rudder and consequently, less weather helm. Another benefit of this modification is that your tiller autopilot (if you have one installed) doesn’t have to work as hard.
You can fabricate a spacer yourself out of any material up to 1″ thick. For best results, use a marine-grade, high-density polyethylene like King StarBoard.
- Remove the rudder from the gudgeons.
- Remove the upper gudgeon screws and gudgeon from the transom. On most C-22s, it’s extremely difficult to get a wrench onto the nuts between the transom and the cockpit sole so the nuts are bonded in place at the factory as shown below so that a wrench is not necessary.
- Clean the fiberglass under the gudgeon thoroughly.
- If the transom holes aren’t countersunk already, use a countersink bit or a 1/2″ HSS drill bit to bevel the gelcoat to twice the hole diameter.
- Trace the gudgeon outline on the spacer material and mark the hole centers.
- Drill the holes with a 1/4″ HSS bit. For best results, use a drill press.
- Cut around the outside of the outline. For best results, use a bandsaw or jigsaw.
- Bevel the back of the spacer 5 degrees to tilt the gudgeon into alignment with its pintle pin. For best results, use a stationary disc sander. In my experience, also tilting the lower gudgeon isn’t necessary but if you have difficulty replacing the rudder in step 11, install a 1/16″ tapered shim under the lower gudgeon or bend the pintle pin slightly towards the rudder with a tap of a hammer until it slips easily into the gudgeon.
- Smooth all cuts and edges with sandpaper. For best results, use a belt or disk sander.
- Replace the gudgeon with the spacer. Use new machine screws at least as much longer than the original screws as the thickness of the spacer. Wrap a small cone of butyl tape around the screws so that it compresses into the countersinks.
- Replace the rudder on the gudgeons.
- Go sailing!
You can achieve this same effect by replacing your entire back-swept rudder with an expensive balanced rudder that is not back-swept but that’s not stingy. You can try this modification without digging deep into your wallet and if you don’t like it, easily remove it.
Note that this modification raises the tiller handle slightly. If you have a tiller autopilot installed as described in How to Install a Tiller Autopilot, this will also raise the end of the autopilot piston, though not enough to adversely affect the autopilot performance.
Unlike some aftermarket balanced rudders, this modification is compliant with the Catalina 22 National Association class rules section B rule 4:
Racers have used this mod for years without penalty.
If you’d like to try this modification but don’t have the time, tools, or skills to make your own spacer, consider purchasing the $tingy Sailor Gudgeon Spacer Kit, which includes everything you need and can be installed in 15 minutes or less.
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6 Comments Add yours
Simple elegant rudder tuning hank.
Wishing you good sailing this season.
From my experimenting with rudder angles to improve helm performance when sailing my Potter 19 between Long Beach, Calif. to Catalina, changing the whole tilt angle of the rudder will cause a lifting drag effect. Changing the pintle’s pivot axis in relation to the rudder axis affects balance. Placing the rudder edge forward of pivot axes. I believe it would be better on a C22 to place a shim between the pintle & rudder, not the gudgeon to the stern of boat.
I cut my wooden kick-up rudder at the tilt joint interface to allow the bottom blade to move forward of the pintle’s pivot axis by about 2 inches. This provided a balance that allowed much less force on the tiller. Before I made this change, I felt that I might break the tiller over the constant swells and wind. Life improved much more after replacing the wood rudder with a nylon kick-up rudder that was balanced. Also being thinner, it sliced through water with less resistance.
Thanks for sharing your experience, Tom. I can see why that would happen on a Potter 19 because its rudder is even more backswept than the C-22 and the transom overhangs slightly. But the C-22 transom is vertical so the spacer has minimal direct effect on tiller pressure, which is more than compensated for by the reduced wet rudder angle. I raced Summer Dance in a regatta a couple of weeks ago, the first time since making this modification. With a full mainsail and full 150 genoa making 6 knots of speed, I could steer with one finger – much more relaxing than before. Making or buying a truly balanced rudder with a NACA foil shape is on my wish list so stay tuned!
What would be the fix for the opposite. Having a boatload of leeward helm and the boat not wanting to turn into the wind? We own a Young 780 and it sometimes refuses to point into the wind if we are too slow. Would that be rudder size
It sounds to me like your sail plan is out of balance under those conditions. That is, too much headsail and not enough mainsail. Try moving the jib cars aft to let the top of the headsail twist and spill a bit of wind and/or trim the headsail to make more power.