Section 5 Machinery

501. General

Machinery installations of the ships are to be in accordance with this section in addition to Ch 3, Sec 4.

502. Jacking systems

Jacking systems of self-elevating ships are to be in accordance with the requirements in Ch 10,

105. of Rules for Mobile Offshore Units.

503. Piping systems for self-elevating ships

1. Bilge systems

(1) A means to indicate whether a valve is open or closed is to be provided at each location from which the valve can be controlled. The indicator is to rely on movement of the valve spindle.

Guidance for Offshore Support Vessels 2015 39

(2) Taking account of purposes and operating mode of the units, the Society may accept one bilge pump notwithstanding the requirements in Pt 5, Ch 6, Sec 4 of Rules for the Classification of Steel Ships.

(3) Notwithstanding the requirements in Pt 5, Ch 6, Sec 4 of Rules for the Classification of Steel Ships, in determination of the internal diameters of the main bilge line and the branch bilge suctions, the following requirements are to be complied:

(A) Branch bilge suction pipes from each compartment are to be of the internal diameter ob- tained from the following formula or the standard pipes of internal diameter nearest to the calculated diameter. In case where the internal diameter of such standard pipes is short of

the calculated value by 5 mm or more, standard pipes of one grade higher diameter are to be used.

Ẁ G ËĦËÈĬJA ĞËÈ Fmm F

where :

Ẁ :

A :

(B) The cross

Internal diameters of the branch bilge suctions (mm ).

Wetted surface of the compartment, excluding stiffening members when the com- partment is half filled with water (mË).

sectional area of the main bilge line is not to be less than the combined areas

of the two largest branch suctions.

2. Air Pipes and Overflow Pipes

Air pipe openings and discharge openings of overflow pipes are to be located above the final cal- culated immersion line in the assumed damage condition specified in Sec 2, and are to be posi- tioned outside the extent of damage, as defined in Sec 2.

3. Sounding pipes

(1) Sounding pipes are to be of the minimum internal diameter 38 mm . Where a sounding pipe ex- ceeds 20 m in length, the minimum internal diameter is to be increased to at least 50 mm .

(2) Where a remote level indicating system is used, an additional sounding system is to be pro-

vided for tanks which are not always accessible.