Transcript Bilge_System

Bilge System
Function
• To drain any watertight compartment other
than ballast, oil or water tanks and to
discharge the contents overboard
• The number of pumps and their capacity
depend upon the size, type and service of
the vessel
Example
• An emergency bilge pump is required for
passenger ships but may also be fitted as an
extra.
• The bilge and ballast systems, while having two
distinct functions to perform in the vessel, could
be so interconnected that it is found
advantageous to cover the two systems on the
same arrangement plan.
(The same pumps are commonly connected
to serve both systems, and the piping with its
valve and fittings must be so arranged that each
system can function without interference with the
other.)
• All bilge suctions must be fitted with suitable strainers,
which in the machinery space would be mud boxes
positioned at floor plate level for easy access. A
vertical drop pipe would lead down to the bilge.
• To enable the internal perforated plate to be cleaned
when necessary, the lid of the mud box is easily
removed without disconnecting any pipework.
• At the end of the bilge lines in other
compartments, ordinary box strainers or
their equivalent are satisfactory provided
they have an open area not less than
three times the area of the suction pipe.
• A non—return valve should be fitted to the
end of the bilge pipe in the compartment
which it serves.
The bilge pumping system must be
capable of dewatering the ship
under all practicable conditions
• A casualty including extreme conditions of
list and trim
• For this purpose, wing suctions are
generally fitted
• The piping design must be such that
miscellaneous water in the compartments
will drain to the bilge suction pipes.
The pump discharge
• Each pump may have a separate
discharge through the side
• but it is desirable that the shell
penetrations be as few as practicable
• therefore, two or more discharge lines are
usually combined in one outlet, each line
being fitted with a valve to permit isolating
the line from the others.
• Bilge pumping systems are arranged so as
to prevent oil or water from passing into
spaces or from passing from one
compartment to another.
MARPOL(marine pollution) or
International Convention for Prevention of
Pollution From Ships
• Oil pollution at sea is limited by MARPOL 1973
legislation which effectively states that: It is an
offence to discharge bilge water contaminated
with more than 100ppm (parts per million) in
some areas only 15ppm fuel or lubricating oil in
a prohibited zone.
• The international oil pollution chart shows the
prohibited zones but generally it includes all
waters within 160 km of the shore including
territorial waters.
• Oil/water separators are used to ensure that
vessels do not discharge oil when pumping out
bilges, oil tanks or any oil—contaminated space.
• Large small craft (20m and above) are today
often fitted with bilge water separates to ensure
that any bilge water discharged conforms to the
regulations regarding purity. This is particularly
applicable to vessels operating in American
waters covered by the U.S. Coast Guard
Regulations
• There is no doubt that the web of these
regulations will be extended and tightened in an
international effort to curb pollution at sea.
Therefore we may be assured that in future Bilge
Separators or Bilge water filtration will be a
compulsory fitment in vessels of all sizes in
future.
• Specific requirements regarding the
number of bilge pumps and their —
capacities are delineated in the regulations.