Section 1 General
Clasification Society 2024 - Version 9.40
Clasifications Register Rules and Regulations - Rules and Regulations for the Classification of Offshore Units, July 2022 - Part 10 Ship Units - Chapter 2 Loads and Load Combinations - Section 1 General

Section 1 General

Parent topic: Chapter 2 Loads and Load Combinations

1.1 Application

1.1.1 This Section provides the design load combinations for the scantling calculations. The loads cover load scenarios for all modes of operation dividing the loads into static load components, dynamic load components, sloshing loads and impact loads. The loads are applicable to ship units of conventional hull form and proportions. If the form and proportions of the hull are outside of those for conventional ship type units then special consideration of the ship motions may be required. Details of the proposed hull design are to be submitted for consideration, and it is recommended this is done at as early a stage as possible.

1.1.2 The values of motions, accelerations and sloshing loads may be derived from direct calculation or obtained from model testing. These should be assessed in relation to Lloyd’s Register’s (LR) own direct calculation procedures.

1.2 Definitions

1.2.1  Coordinate system.
  1. The applied coordinate system used within these Rules is defined with respect to the right-hand coordinate system.
1.2.2  Sign conventions.
  1. Positive motions, as shown in Figure 2.1.1 Definition of positive motions, are defined as:
    1. positive surge is translation along positive x-axis (forward);
    2. positive sway is translation along positive y-axis (towards port side of vessel);
    3. positive heave is translation along positive z-axis (upwards);
    4. positive roll is starboard down and port side up;
    5. positive pitch is bow down and stern up;
    6. positive yaw is bow rotating towards port side of vessel and stern towards starboard side.
  2. Positive accelerations are defined as:
    1. positive longitudinal acceleration is acceleration along positive x-axis (forward);
    2. positive transverse acceleration is acceleration along positive y-axis (towards port side of vessel);
    3. positive vertical acceleration is acceleration along positive z-axis (upwards).
  3. The sign convention of positive vertical hull girder shear force is shown in Figure 2.1.2 Positive vertical shear force.
  4. The sign conventions of positive hull girder bending moments are shown in Figure 2.1.3 Positive vertical bending moment and Figure 2.1.4 Positive horizontal bending moment, and are defined as:
    1. positive vertical bending moment is a hogging moment and negative vertical bending moment is a sagging moment;
    2. positive horizontal bending moment is tension on the starboard side and compression on the port side.
1.2.3  Density.
  1. The density is not to be taken as less than minimum density value, as defined in Table 2.1.1 Minimum density of liquid for strength and fatigue assessment.

    Figure 2.1.1 Definition of positive motions

    Figure 2.1.2 Positive vertical shear force

    Figure 2.1.3 Positive vertical bending moment

    Figure 2.1.4 Positive horizontal bending moment

    Table 2.1.1 Minimum density of liquid for strength and fatigue assessment

    Liquid Scantling and strength Fatigue Sloshing Ultimate strength
    Cargo oil The greater of 1,025 t/m3 or actual Mean The greater of 1,025 t/m3 or actual The greater of 1,025 t/m3 or actual
    Ballast water 1,025 t/m3 1,025 t/m3 1,025 t/m3 1,025 t/m3
    Sea-water, 1,025 t/m3 1,025 t/m3 1,025 t/m3 1,025 t/m3
    Condensate The greater of 1,025 t/m3 or actual Mean The greater of 1,025 t/m3 or actual The greater of 1,025 t/m3 or actual
    Chemicals The greater of 1,025 t/m3 or actual Mean The greater of 1,025 t/m3 or actual The greater of 1,025 t/m3 or actual
    Liquefied gas Maximum density of the liquefied gas Mean density of the liquefied gas Maximum density of the liquefied gas Maximum density of the liquefied gas
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