Rudder Steering Gearbox

Steering gear box, drive shaft, and steering buster pump salvaged from a school bus.

While cutting our school bus apart I noticed that huge steering gear box with it’s 2″ splined steel shaft. If it can steer a 7 ton bus on land, it shouldn’t it be able to steer a 40 ton boat on water? Unfortunately No! It would be great for a 6 ton boat with a 2″ rudder post, but when we ran our numbers through the calculations in Dave Gerr’s “Boat Mechanical Systems Handbook” our 40 ton, 65′ water line boat with a 23 square foot rudder, needs rudder post in excess of 4 1/2 inch diameter bar that can take over 7 tons of force and 21,000 foot pounds.

If you get at all nervous about boat building decisions then looking at rudders will likely make your head explode. The real killer is they are not like anchors. You can trade this part out easily. My only advice is keep in mind how you are going to use your boat.

For us, Seeker is a work boat. Towing, hauling cargo, maneuverability, and ruggedness are top of the list. Meaning that speed under sail is going to take a hit.

www.rudderpower.com

www.rudderpower..com

One answer to tight turns is the articulating rudder. The make for impressive turns but the down side is the additional moving parts and the maintenance that come with that. Their other down side is that they work very poorly in reverse.

Kort Nozzle

Rice Nozzle