Section 6 Rudder Plates, Rudder Frames and Rudder Main Pieces

601. Rudder plate

The rudder plate thickness is not to be less than that obtained from the following formula

mm

×

: as defined in the following

maximum :

2.0 (for steel), or 0 (for stainless steel, composite material and aluminium).

: spacing of horizontal or vertical rudder frames, whichever is smaller (m ).

spacing of horizontal or vertical rudder frames, whichever is greater (m ).

: material factor of rudder plate as given in 102.

: as specified in Pt 3, Ch 1, 106.

602. Rudder frames

1. The rudder body is to be stiffened by horizontal and vertical rudder frames enabling it to act bending girder.

2. The standard spacing of horizontal rudder frames, is to be obtained from the following

as a

m

3. The standard distance from the vertical rudder frame forming the rudder main piece to the adjacent vertical rudder frame is to be 1.5 times the spacing of the horizontal rudder frames.

4. The thickness of rudder frames is not to be less than 8 mm or 70 % of the thickness of the rudder plates as given in 601. whichever is greater.

603. Rudder main pieces

1. Vertical rudder frames forming the rudder main piece are to be arranged forward and afterward of the centerline of the rudder stock at a distance approximately equal to the thickness of the rudder where the main piece consists of two rudder frames, or at the centerline of the rudder stock where the main piece consists of one rudder frame.

2. The section modulus of the main piece is to be calculated in conjunction with the vertical rudder frames specified in Par 1 and rudder plates attached thereto. The effective breadth of the rudder

plates normally taken into calculation are to

(1) Where the main piece consists of two length of the main piece.

(2) Where the main piece consists of one length of the main piece.

3. The section modulus and the web area of

be as follows :

rudder frames, the effective breadth is 0.2 times the rudder frame, the effective breadth is 0.16 times the

a horizontal section of the main piece are to be such

that bending stress, shear stress and equivalent stress will not exceed the following stress values, respectively.

N mm

N mm

N mm

: material factor for the rudder main piece as given in 102.

4. The upper part of the main piece is to be constructed so as to avoid structural discontinuity.

604. Connections

Rudder plates and frames are to be effectively connected and free from defects.

605. Paintings and drainage

The internal surface of the rudder is effectively coated with paint, and a means for drainage be provided at the bottom of rudder.

is to