3.3 Drifting tests
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Statutory Documents - IMO Publications and Documents - Circulars - Maritime Safety Committee - MSC.1/Circular.1227 – Explanatory Notes to the Interim Guidelines for Alternative Assessment of the Weather Criterion – (11 January 2007) - Annex - Explanatory Notes to the Interim Guidelines for Alternative Assessment of the Weather Criterion - 3The determination of the wind heeling lever lw1 - 3.3Drifting tests

3.3 Drifting tests

  3.3.1 The drifting test was carried out in a basin with dimensions of 50 m in length, 8 m in breadth and 4.5 m in depth. The set-up is shown in figure 3.3. To connect the model, the load cell and the heaving rod the same connection setup as in the wind tunnel tests was used. The horizontal force Fwater and the heeling moment M were measured by the load cell. They were determined as time averages in stationary condition after the transient phase, which appears when the carriage starts to run. The heeling moment with respect to point O, defined as Mwater , was calculated similarly to the wind tunnel tests. However, the last term in equation (N-3.2) is not necessary since the vertical force is globally zero due to heave-free arrangement.

The arrangment for drifting test

  3.3.2 The drifting speed should be determined to make the drifting force equal to Fwind as defined by equation (1.2) of the Guidelines in model scale. The wind speed should be assumed to be 26 m/s in ship scale. However, in this experiment, the speed was varied to cover the expected range of the wind drag coefficient, C D , since the wind tunnel tests were carried out after the drifting tests.

Parent topic: 3 The determination of the wind heeling lever lw1
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