Topic - 18 Watertight Bulkheads

Arrangements of Watertight Bulkheads

1.       Collision Bulkhead

All barges are to be fitted with a collision bulkhead extending intact to the freeboard deck in one plane.

The collision bulkhead is to be located at a distance aft of the forward perpendicular (See 3-1-1/27) not less than given by the following:

0.05L= meters                      where L < 200 meters   (3-2-6/3.1)

And

The collision bulkhead is to be located at a distance aft of the forward perpendicular (See 3-1-1/27), except as specially permitted, not more than given by the following:

0.05L + 3.66 = meters         where L < 122 meters       (3-2-6/3.2)

2.       Other Watertight Bulkheads

Watertight bulkheads are to be arranged to provide a reasonable standard of subdivision.

The following is recommended as a guide to determine the maximum spacing between transverse watertight bulkheads in single bottom deck cargo barges, but is not required as a condition of classification:

S = 0.153L + 3.81 m for L < 122 m      (3-2-6/3.3)

                                  = m

3.       Construction of Watertight Bulkheads 

Ø  Plating

Plating of watertight bulkheads is to be of the thickness obtained from the following equation:

t = sk√qh/c + 1.5 mm     (3-2-6/5.1)

For collision bulkhead = mm

Finalized collision bulkhead thickness = mm

Watertight bulkhead = mm 

Finalized Watertight bulkhead thickness = mm

     But not less than 6 mm (0.24 in.) or s/200 + 2.5 mm (s/200 + 0.10 in.), whichever is greater.

Ø  Stiffeners

Each stiffener, in association with the watertight bulkhead plating to which it is attached, is to have a section modulus SM not less than obtained from the following equations:

SM = 7.8chsl²Q cm³       SM = 0.0041chsl²Q in³      (3-2-6/5.3)

                             = cm³      

     Depth considered = in.

     Web thickness = in.

     Flange thickness = in.

     Flange width =   in.

                                         SM_obtained = cm³

4.      Stringers and Webs

Ø  Strength Requirements

Each stringer or web which supports watertight bulkhead stiffeners is to have a section modulus SM not less than obtained from the following equation:

SM = 4.74chsl²Q cm³            SM = 0.0025chsl²Q in³ (3-2-6/5.5)

                           = 242.23 cm³

     Depth considered = in.

     Web thickness =  in.

     Flange thickness = in.

     Flange width =   in.

                                         SM_obtained = cm³

The section modulus SM of each stringer or web on the collision bulkhead is to be at least 25% greater than required for similar supporting members on other watertight bulkheads. 

 SM of each stringer on collision bulk head = cm³

     Depth considered =  in.

     Web thickness =  in.

     Flange thickness = in.

     Flange width =  in.

                                         SM_obtained = cm³

Ø  Proportions

Stringers and webs are to have depths not less than 83.5 mm per meter of span l (1 in. per foot of span l). See also 3-2-4/3.9iv).

                                          Stringer and web depth = mm

Finalized Depth = mm. (For other water tight bulkhead)

                          = mm (For collision bulkhead)

5.      Tripping Brackets

Tripping brackets are to be fitted at intervals of about 3 m (10 ft), and are to be arranged to support the flange.