A semi-balanced rudder has a shorter Vertical section forward of the stock, thus less counterbalance than the “balanced” rudder, but more than the unbalanced rudder. The semi-balanced rudder often need more torque than the balanced rudder. And it is a very widely used kind of rudder for modern tonnage, especially for the container type vessel and twin-screw vessels.
Favourite and SURE Questions of MMD Surveyors here
 |
| semi balanced rudder in action. |
Rudders types are a very important for ship's fuel efficiency.
ReplyDeleteUnbalanced rudders need lots of torque and are useful for small crafts.
Balanced rudders need minimum torque but are not preferable due to disadvantages because of substantial forward section.
However, semi balanced rudders are considered the best due to many reasons. It's very effective as major portion is after of the fulcrum and tends to come to amidships, when power is lot.