Page 202 - Ship Construction.DJ Eyres 6Ed

Ch18-H8070.fm Page 191 Wednesday, October 18, 2006 6:58 AM

18
Bulkheads and Pillars

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งานห้องสมุด ศูนย์ฝกพาณิชย์นาวี
This chapter deals with the internal vertical structure of the ship. Much
of this structure, particularly the pillars and to some extent the transverse
strength bulkheads, is responsible for carrying the vertical loading experi-
enced by the ship. The principal bulkheads subdivide the ship hull into
a number of large watertight compartments, and their construction and
spacing is discussed. Also considered are the boundaries of other smaller
compartments such as deep tanks and the shaft tunnel.

Bulkheads
ึ
Vertical partitions in a ship arranged transversely or fore and aft are referred
to as ‘bulkheads’. Those bulkheads which are of greatest importance are the
main hull transverse and longitudinal bulkheads dividing the ship into a
number of watertight compartments. Other lighter bulkheads, named ‘minor
bulkheads’, which act as screens further subdividing compartments into
small units of accommodation or stores, are of little structural importance.
The main hull bulkheads of sufficient strength are made watertight in
order that they may contain any flooding in the event of a compartment on
one side of the bulkhead being bilged. Further they serve as a hull strength
member not only carrying some of the ship’s vertical loading but also resist-
ing any tendency for transverse deformation of the ship. As a rule the
strength of the transverse watertight bulkheads is maintained to the strength
deck which may be above the freeboard deck. Finally each of the main hull
bulkheads has often proved a very effective barrier to the spread of a hold
or machinery space fire.

SPACING OF WATERTIG HT BULKHEADS – CARGO SHI P S The
minimum number of transverse watertight bulkheads which must be fitted
in a dry cargo ship are stipulated. A collision bulkhead must be fitted
forward, an aft peak bulkhead must be fitted, and watertight bulkheads
must be provided at either end of the machinery space. This implies that for
a vessel with machinery amidships the minimum possible number of water-
tight bulkheads is four. With the machinery aft this minimum number may