Overview

This book provides the Master of a disabled tankers with information about the most probable drift behaviour of their ship.

The research underpinning the book was initiated by a group of OCIMF member companies, the American Institute of Merchant Shipping (AIMS) and the International Salvage Union (ISU). The British National Maritime Institute (NMI) was commissioned to carry out intensive model testing with free floating and tethered models that was validated with full scale drift data obtained from a number of vessels, predominantly VLCC's but also some smaller tankers.

Content

1. Introduction

1.1 Purpose of Investigation

1.2 Details of Models

1.3 Synopsis of Experiments and Computations

2. Experiments with Free Models

2.1 Description of Experimental Method

2.2 Calculation Wind Forces and Moments

2.3 Arrangement of Test Series

2.4 Results: Twin-Screw Model 5481

2.4.1 Free-Drift Experiments

2.4.2 Manoeuvring with Limited Power Available

2.4.3 Manoeuvring with Rudders Flying Free

2.5 Results: Bulbuos-Bow Model 5480A

2.5.1 Free-Drift Experiments

2.5.2 Manoeuvring with Limited Power Available

2.5.3 Manoeuvring with Rudder Flying Free

2.5.4 Effect of Heel with Power Available

2.5.5 Force to Move Model out of Trough

2.5.6 Wind and Waves from Different Directions

2.6 Results: Rounded Bow Model 5480B

2.6.1 Free-Drift Experiments

2.6.2 Manoeuvring with Limited Power Available

2.6.3 Manoeuvring with Rudder Flying Free

2.6.4 Effect of Heel with Power Available

2.6.5 Force to Move Model out of Trough

2.6.6 Wind and Waves from Different Directions

2.7 A Note of Coriolis Effects

2.8 Summary of Main Conclusions

2.8.1 Free-Drift

2.8.2 Controlled Drift

2.8.3 Towing Forces to Head into Weather

3. Measurements of Drift Forces in Waves

3.1 Experiment Arrangement

3.1.1 Introduction

3.1.2 Programme of Tests

3.1.3 Sea-State Spectra

3.1.4 Mooring Arrangements

3.1.5 Force Measurements

3.1.6 Instrumentation

3.1.7 Conduct of the Tests

3.2 Results Obtained

3.2.1 Method of Presentation

3.2.2 Accuracy and Repeatability

3.2.3 Effect of Wave Encounter Angle

3.2.4 Effect of Seastate

3.2.5 Effect of Rudder

3.2.6 Effect of Hull Shape

3.2.7 Effect of Trim

3.3 Conclusion

4. Calculations of Drift Forces in Waves

4.1 Introduction

4.2 Method of Calculation

4.3 Ship Models

4.3.1 Model 5480B

4.3.2 Modified Model with L/B=4.5

4.3.3 Natural Periods

4.4 Spectral Model

4.5 Numerical Models

4.6 Results

4.6.1 Regular Waves

4.6.2 Irregular Waves

4.7 Comments on Results

4.7.1 Regular Waves

4.7.2 Irregular Waves

4.8 Comparisons between Calculated and Measured Results

5. Conclusion

6. References

Details

Title: Disabled Tankers - Report of Studies on Ship Drift & Towage
Number of Pages: 252
Product Code: 4400W009
ISBN: ISBN 13: 978-0-900886-63-8 (9780900886638), ISBN 10: 0-900886-63-3 (0900886633)
Published Date: January 1981
Binding Format: Paperback
Book Height: 297 mm
Book Width: 210 mm
Book Spine: 14 mm
Weight: 0.80 kg