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4. VALIDATION
The empirical formulae for maneuvering predictions are usually used for two purposes in design stage. One is the accurate maneuvering prediction for designed ship and the other is the precise evaluation about the effect of the hull parameter variations before the hull form is designed. Therefore, the efficiency of empirical formulae are to be validated through comparisons with sea trial results for the accuracy of predictions and with PMM test results for checking the maneuverability according to the main dimension and hull form variations.
The comparisons between the prediction results using proposed empirical formulae and sea trial results including full load and ballast conditions are carried out. The full load results are mainly those of tankers and product carriers and the ballast results are those of bulk carriers, container carriers and LNG carriers as shown in Table 1. The sea trials have been recently carried out and the results are based on the averaged starboard and port trials to reduce the environmental effects.
Table 1 Number of Ships in Sea Trial
| |
No. of Ships |
| Full Load |
Ballast |
Total |
| Tanker |
3 |
1 |
4 |
| Product Carrier |
4 |
0 |
4 |
| Bulk Carrier |
0 |
2 |
2 |
| Container |
1 |
2 |
3 |
| LNG Carrier |
0 |
1 |
1 |
|
The comparisons between the predictions and sea trial data are shown in Figures 10 to 14.
Fig.10 |
Comparisons between Sea Trial and Estimated Advance |
Fig. 11 |
Comparisons between Sea Trial and Estimated Tactical Diameter |
Fig.12 |
Comparisons between Sea Trial and Estimated 1st O.A. of 10°/10° Zigzag maneuver |
Fig.13 |
Comparisons between Sea Trial and Estimated 2nd O.A. of 10°/10° zigzag maneuver |
Fig.14 |
Comparisons between Sea Trial and Estimated 1st O.A. of 20°/20° Zigzag maneuver |
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