Sketching Out Installation Options

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I worked through the alternative steering geometries and forces using trigonometry. An easier way to evaluate various installations is to use a triangle, ruler, and compass and draw the geometry of each setup. Note practical socket and tiller-pin locations. The tillerpilot will need to be level, but ignore that for the moment. I made four drawings before deciding on just two options worth field testing:

 

Image 1. The socket is located 24.5 inches to the side of the centered tiller, just like the instructions say. The pin is located at 14 inches, 18 inches (factory recommendation), and 21 inches forward of the rudder stock, and the socket is located at matching distances, maintaining a 90-degree angle to the tiller when centered. In each position, the maximum port and starboard rudder angles are identical. The push-rod delivers maximum force, and the total helm angle ranges from 26 degrees to 42 degrees.

The 14-inch position meets my average condition tacking requirement (40 degrees). It may fall a little short of optimum in a heavy seaway, but I can make up the difference with better technique. The 14-inch setup requires the most modification to work on our F-24, but it achieves performance that is closer to what we expect.

Sketching Out Installation Options

Image 2. We tried keeping the socket at 21 inches and moving only the tiller-pin to 14 inches. The range to the far side of the cockpit (when making a turn to starboard) is barely changed. The range on the near side (port turn) improved, but at the cost of terrible leverage, resulting in 2½ times the push-rod force (45 pounds) required compared to the standard position. Even with this very light boat, this exceeds our preferred force limits.

We also tried this setup with an extended push-rod. Using an .8-inch extender on the push-rod, the tiller range was centered and performance improved, but the leverage in a starboard turn was still poor.

VALUE GUIDE: CORSAIR F-24 HELM DATA

TYPICAL TACKING DATA 
HELM DATA DEGREES OF HELM (TOTAL) MAXIMUM HELM FORCE (31-INCH TILLER) 
TYPICAL TACKING HELM 20 degrees (40 degrees) 10 lbs. 
MAXIMUM ANGLE OF HELM APPLIED WHILE TACKING 30 degrees (60 degrees) 10 lbs. 
TYPICAL WHEEL STEERING RANGE 35 degrees (70 degrees) 10 lbs. 

TECH GUIDE: TILLERPILOT INSTALLATION

(1) VARYING TILLERPILOT MOUNTING SOCKET AND TILLER-PIN LOCATION 
DIMENSION A (MOUNTING SOCKET’S DISTANCE FORWARD OF RUDDER STOCK) MAXIMUM RUDDER ANGLE (TOTAL RANGE) PUSH-ROD FORCE TO EQUAL 10 POUNDS MANUAL STEERING 
21 INCHES 13 degrees (26 degrees) 15 lbs. 
TEST BOAT’S INSTALLATION 
18 INCHES MANUFACTURER’S RECOMMENDED INSTALLATION 16 degrees (32 degrees) 18 lbs. 
14 INCHES ALTERNATIVE TESTED INSTALLATION 21 degrees (42 degrees) 24 lbs. 
(2) NEW TILLER-PIN POSITION BUT MAINTAINING DRIVE SOCKET AT 21 INCHES 
DIMENSION A (TILLER-PIN’S DISTANCE FROM RUDDER STOCK) MAXIMUM RUDDER ANGLE (TOTAL RANGE) PUSH-ROD FORCE TO EQUAL 10 POUNDS MANUAL STEERING 
21 INCHES (ORIGINAL INSTALLATION) 13 degrees (26 degrees) 15 lbs. 
14 INCHES* 32° port/15° starboard* (47 degrees)45 lbs. 
Darrell Nicholson
Darrell Nicholson is Director of Belvoir Media Group's marine division and the editor of Practical Sailor. A lifelong thalassophile, he grew up sailing everything from El Toro dinghies to classic Morgans on Miami's Biscayne Bay. In the early 90s, he left a newspaper job to sail an old gaff-rigged ketch across the Pacific and has been writing about boats and the sea ever since. His weekly blog Inside Practical Sailor offers an inside look at current research and gear tests at Practical Sailor, while his award-winning column,"Rhumb Lines," tracks boating trends and reflects upon the sailing life. He sails a Sparkman & Stephens-designed Yankee 30 out of St. Petersburg, Florida. You can reach him at darrellnicholson.com.