HelmSteering Box
While cutting our school bus apart I noticed that huge steering gear box with it's 1 1/2" splined steel shaft. If it can steer a 7 ton bus on land, it should be able to steer a 40 ton boat on water. The area of the rudder is about 25 square feet. Some of that is actually above the water line so really about 22.6 square feet of surface area is always below the water line. Up to 20% of the area or about 4.5 square feet can be forward of the rudder post to act as a counter balance and make rudder easier turn. If the forward edge of the rudder is 9 inches from the center of the rudder then the counter balance area is 4.2 square feet and safely within the recommended size. If this rudder need to be increased in size, it can be done with the addition of a deflector tab on the trailing edge or simply extending the trailing edge.
Rudder Variations
Articulating Rudder
Resources
www.kobelt.com/product-steering.php Rules of Thumb For manual hydraulic systems, under normal conditions, the load on the steering wheel rim should not exceed 36 ft. lbs. (16 kg), and generally the hydraulic system pressure should not exceed 650 psi (45 bar) for small helm pumps or 400 psi (30 bar) for larger versions. A rudder area of between 8 and 10 per cent of the total lateral plane or underwater profile is the desirable size for a sailboat. Seeker is about 304 sq feet * .08 = 24.6 sq ft. The submerged portion of the rudder is typically 1% to as much as
2% of the sail area.
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