Section 4 Bilge drainage of machinery spaces

4.1.1 The bilge drainage arrangements in the machinery space are to comply withPt 5, Ch 11, 3.1 General, except that the arrangements are to be such that any water which may enter this compartment can be pumped out through at least two bilge suctions when the ship is on an even keel, and is either upright or has a list of not more than 5°. One of these suctions may be a branch bilge suction, i.e. a suction connected to the main bilge line, and the other is to be a direct bilge suction, i.e. a suction led direct to an independent power pump. An example of the necessary arrangements is detailed in Pt 5, Ch 11, 4.1 General 4.1.3.

4.1.2 In passenger ships, the drainage arrangements are to be such that machinery spaces can be pumped out under all practical conditions after a casualty, whether the ship is upright or listed.

4.1.3 In ships in which the propelling machinery is situated at the after end of the ship, it will generally be necessary for bilge suctions to be fitted in the forward wings as well as in the after end of the machinery space, but each case will be dealt with according to the size and structural arrangements of the compartment.

4.2.1 For ships other than passenger ships where a bilge main is not fitted, the branch bilge suction referred to in Pt 5, Ch 11, 4.1 General 4.1.1 and Pt 5, Ch 11, 4.1 General 4.1.3 may be replaced by a suction from fixed installed submersible pumps in accordance with 6.6. The second bilge suction is to be either a second fixed installed submersible bilge pump or a direct bilge suction as detailed in Pt 5, Ch 11, 5.3 Direct bilge suctions. The capacity of each pump is to be in accordance with Pt 5, Ch 11, 6.3 Capacity of pumps with d _m calculated as the main bilge in accordance with Pt 5, Ch 11, 5.1 Main bilge line 5.1.1.

4.2.2 An emergency means of pumping out the compartment is to be provided where fixed submersible pumps will be fitted. The emergency bilge pumping arrangements may be provided by a portable submersible self-priming pump of a capacity not less than that required by Pt 5, Ch 11, 6.3 Capacity of pumps.

4.2.3 The pump referred to in Pt 5, Ch 11, 4.2 Submersible pump drainage 4.2.2 together with its suction and delivery hoses is to be stored in a secure and safe locker marked ‘For emergency use only’, accessible from open deck and clear of the machinery space(s). The pump is to be available for immediate use. If the pump is electrically driven, it is to be supplied from the emergency switchboard.

4.3.1 For ships other than passenger ships where the bilge main is not separated as per Pt 5, Ch 11, 7.2 Isolation of bilge system 7.2.1, the branch bilge suctions referred to in Pt 5, Ch 11, 4.1 General 4.1.1 and Pt 5, Ch 11, 4.1 General 4.1.3 may be connected to the common suction pipe between the two bilge pumps, provided one automatic non-return valve is fitted in each branch bilge suction in addition to the screw-down non-return valve required by Pt 5, Ch 11, 7.1 Prevention of communication between compartments 7.1.1.