Section 1 Standard load scenarios

1.1.1 The requirements in the Rules use standard load scenarios as the basis of interpreting the application of FS Rules and PC Rules to the ship structure, machinery and arrangement. Standard load scenarios are used to indicate the operations identified as resulting in the most critical loading due to stern first operation in ice assumed in these Rules.

1.1.2 Application of the Rules where the intention for stern first operation indicates that alternative load scenarios to those assumed in Ch 2, 1.2 Hull load scenarios and Ch 2, 1.3 Propulsion unit load scenarios may be more critical will receive special consideration based on load scenarios submitted. See Ch Ch 6, 2 Framework for non-standard load scenarios.

1.2.1 The hull standard load scenarios are the operational scenarios considered to give the most critical loading conditions for the stern hull structure of a Stern First Ice Class Ship. Non-standard load scenarios for the hull may be used in determining loads based upon the operational scenarios developed by the designer.

1.2.2 For Stern First Ice Class Ships, the hull standard load scenarios are considered to be a combination case of ridge crossing and turning in ice. The standard load scenarios consider these operations with respect to contact of the hull with the consolidated layer of the ridge and contact of the hull with the consolidated layer of a channel side whilst turning. See Table 2.1.1 Hull standard load scenario.

1.3.1 For Stern First Ice Class Ships, the propulsion unit standard load scenarios are considered to be a combination of scenarios associated with the crossing of ice ridges:

1. Stopped propeller in ridge keel (impact of propeller with ice sufficient to stop propeller rotation) where the propulsion unit body collects ice load from the ridge keel.

2. Ice sheet consolidated layer crushing at strut.

1.3.2 For the propulsion unit propeller, the standard load scenario is a blade breaking on a thick ice sheet.

1.3.3 The standard load scenario for consideration of the load cases for propulsion unit is given in Table 2.1.2 Propulsion unit standard load scenario and shown schematically in Figure 2.1.1 Propulsion unit standard load scenario.