THE EVALUATION OF LIFEBOAT FORWARD VELOCITY CAPABILITY SUBJECT TO EXTREME CONDITIONS AT THE OFFSHORE INSTALLATIONS

Yıl 2020, Sayı: 19, 31 - 40, 16.09.2020

Özgür Özgüç

Öz

For the offshore installations, dropping lifeboats are employed as a last reserve evacuation method. Lifeboats normally rest on the skid, which is mounted on the mother vessel, until the hook holding the lifeboat rests. It is important that lifeboat diving is a safe method of evacuation. This study describes the capability assessment with respect to the forward speed of the lifeboats under extreme storm conditions. Hence, the aim of the analysis is to determine the limiting storm conditions where the lifeboats are still able to maneuverer away from the offshore installation. The findings of this work are in accordance with the simplified methods, where the North Sea is considered as the suitability of lifeboats under extreme storm conditions. The findings show that the lifeboats cannot propagate forward in storm conditions where the
significant wave height is larger than 11 m. In addition, the net forward force for sea states with wave heights of 10 m and 11 m is rather small and hence the lifeboats may not be able to propagate forward with sufficient velocity.

Anahtar Kelimeler

lifeboat, offshore installation, wind force, storm condition, North Sea

Kaynakça

• [1] DNVGL- RP-C205. Environmental Conditions and Environmental Loads, 2019.
• [2] Prini, F., Birmingham, R. W., Benson, S., Phillips, H. J., Sheppard, P. J., Mediavilla Varas, J., and Dow, R. S. (2016). Motions and loads of a high-speed craft in regular waves: prediction and analysis. In 24th International HISWA Symposium on Yacht Design and Yacht Construction, Amsterdam, NL (pp. 1-14).
• [3] Svendsen, A. G. (2017). Hydrodynamic effects regarding free-fall lifeboat for compressible air in CFD simulations (Master's thesis, NTNU), Norway.
• [4] Groth, S. (2017). Structural loads on a free-falling lifeboat (Master's thesis, NTNU), Norway.
• [5] Myrseth, E., & Tronstad, L. (2016). Challenges with Free Fall Lifeboat Performance in Rough Weather; Analyses, Improvements and Operational Risk Reducing Measures for Use of Free Fall Lifeboats on the Norwegian Continental Shelf. In SPE International Conference and Exhibition on Health, Safety, Security, Environment, and Social Responsibility. Society of Petroleum Engineers.
• [6] Fouques, S., Croonenborghs, E., Aksnes, V., Luxcey, N., Reinholdtsen, S. A., and Jokstad, C. (2013). Establishment of operational criteria for safe launch of free-fall lifeboats from a turretmoored FPSO. In OTC Brasil. Offshore Technology Conference.
• [7] Sauder, T., Croonenborghs, E., Fouques, S., Berchiche, N., and Reinholdtsen, S. A. (2014). Effect of wind loads on the performance of free-fall lifeboats. In ASME 2014 33rd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers.
• [8] Tregde, V., and Nestegård, A. (2014). Prediction of irregular motions of free-fall lifeboats during drops from damaged FPSO. In ASME 2014 33rd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers.
• [9] Ji, G., Berchiche, N., Fouques, S., Sauder, T., and Reinholdtsen, S. A. (2015). Integrity Assessment of a Free-Fall Lifeboat Launched From a FPSO. In ASME 2015 34th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers.
• [10] Luxcey, N., Reinholdtsen, S. A., Sauder, T., Fouques, S., Jin, J., Kauczynski, W., and Hovland, G. (2014). Influence of wave-induced skid motions on the launch of free-fall skid lifeboats from floating hosts: Experimental and numerical investigations. In ASME 2014 33rd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers.
• [11] Mak, L., Simões Ré, A., Sullivan, M., and Kennedy, E. (2005). Assessment of Totally Enclosed Propelled Survival Craft (TEMPSC) Hull Design Performance in Ice Covered Waters. National Research Council, Canada.