4.9.1 An efficient bilge pumping system should
                           be provided, capable of pumping from and draining watertight compartments
                           other than spaces permanently appropriated for the carriage of fresh
                           water, water ballast, oil fuel or liquid cargo and for which other
                           efficient means of pumping are provided, under all practical conditions
                           whether the unit is upright or inclined, as specified in paragraph
                           4.1.4. Additional suctions should be provided in large compartments
                           or compartments of unusual form, as deemed necessary by the Administration.
                           Arrangements should be made whereby water in the compartment may find
                           its way to the suction pipes. Compartments not provided with a bilge
                           suction may be drained to other spaces provided with bilge pumping
                           capability. Means should be provided to detect the presence of water
                           in such compartments which are adjacent to the sea or adjacent to
                           tanks containing liquids and in void compartments through which pipes
                           conveying liquids pass. If the Administration is satisfied that the
                           safety of the unit is not impaired the bilge pumping arrangements
                           and the means to detect the presence of water may be dispensed with
                           in particular compartments.
                        
                        
                        
                      
                     
                     
                     
                        
                        
                         
                           4.9.2 At least two self-priming power pumps connected
                           to each bilge main should be provided. Sanitary, ballast and general
                           service pumps may be accepted as independent power bilge pumps if
                           fitted with the necessary connections to the bilge pumping system.
                        
                        
                        
                      
                     
                     
                     
                        
                        
                         
                           4.9.3 All bilge pipes should be of steel or other
                           suitable material having properties acceptable to the Administration.
                           Special consideration should be given to the design of bilge lines
                           passing through ballast tanks taking into account effects of corrosion
                           or other deterioration.
                        
                        
                        
                      
                     
                     
                     
                        
                        
                         
                           4.9.4 The arrangement of the bilge pumping system
                           should be such as to prevent the possibility of water passing from
                           the sea into dry spaces, or inadvertently from one compartment to
                           another.
                        
                        
                        
                      
                     
                     
                     
                        
                        
                         
                           4.9.5 All distribution boxes and manually operated
                           valves in connection with the bilge pumping arrangements should be
                           in positions which are accessible under ordinary circumstances. Where
                           such valves are located in normally unmanned spaces below the assigned
                           load line and not provided with high bilge water level alarms, they
                           should be operable from outside the space.
                        
                        
                        
                      
                     
                     
                     
                        
                        
                         
                           4.9.6 A means to indicate whether a valve is open
                           or closed should be provided at each location from which the valve
                           can be controlled. The indicator should rely on movement of the valve
                           spindle.
                        
                        
                        
                      
                     
                     
                     
                        
                        
                         
                           4.9.7 Drainage of hazardous areas should be given
                           special consideration having regard to the risk of explosion (see
                           paragraph 6.3.2).
                        
                        
                        
                      
                     
                     
                     
                        
                        
                         
                           4.9.8 The following additional provisions are
                           applicable to column-stabilized units:
                        
                        
                        
                        
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                                 .1 Chain lockers which, if flooded, could substantially
                                 affect the unit’s stability should be provided with a remote
                                 means to detect flooding and a permanently installed means of dewatering.
                                 Remote indication of flooding should be provided at the central ballast
                                 control station.
                               
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                                 .2 At least one of the pumps referred to in paragraph
                                 4.9.2 and pump-room bilge suction valves should be capable of both
                                 remote and local operation.
                               
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                                 .3 Propulsion rooms and pump-rooms in lower hulls
                                 should be provided with two independent systems for high bilge water
                                 level detection providing an audible and visual alarm at the central
                                 ballast control station.