Section 4 Hull Equipment

401.

1.

General

Hull equipment is to be in accordance with this section in addition to relevant requirements in each chapter of Pt 4 and Pt 10 of Rules for the Classification of Steel Ships.

2. In cases where equipment and devices for the ship's purpose are fitted, suitable measures are to be taken so that ship safety is not impaired.

402.

Supporting Structure Design Loads

1. Acceleration Loads

Ship structures supporting cranes are to be designed considering acceleration loads given below. Acceleration loads need not be combined with normal lifting operation loads of the cranes.

ČĐ Ņ LǾÌLĪ × ON← Ň ÃÕKLŃŒE ČÃ Ņ ČD Ņ LǾJE

where:

ČĐ = vertical force (kN)

ČÃ = longitudinal force (kN) ČD = transverse force (kN) Ã = length (m)

E = supported weight (kN)

The value of “x” is dependent on the location of the center of gravity of the specific equipment and is to be taken as that given in the table 6.2. The value of “x” at intermediate locations is to be determined by interpolation. L is to be measured from AP to forward.

Guidance for Offshore Support Vessels 2015 33

Table 6.2 The value of “x” is dependent on the specific equipment

location of the center of gravity of the

Alternatively, accelerations derived from other recognized standards or direct calculations, model tests considering the most serve environmental conditions the vessel is expected to encounter may be considered.

2. Lifting Loads

Maximum expected operational loads are to be applied for calculating scantlings of supporting structure.

3. Acceptable Stresses

Scantlings of structure supporting cranes are to based on the permissible stresses given below: Normal Stress = 0.7 ŖŻ

Shear Stress = 0.4 ŖŻ

Equivalent stress = 0.8 ŖŻ

where ŖŻ is the specified minimum tensile yield strength or yield point.