Dynamic Analysis of the De-Ballasting Operations of a Floating Dock with a Malfunctioning Pump

Abstract

During normal de-ballasting operations for floating docks, each ballast pump independently manages a specific group of ballast tanks. However, when a pump malfunctions, a connection valve between the two groups of ballast water systems is opened. This allows the adjacent pump to serve as a helper pump, simultaneously controlling two groups of ballast water systems. This study explores a full-scale floating dock’s dynamic behaviours during the de-ballasting operations under this situation through a numerical model. In the developed numerical model, the dock is described as a six-degree-of-freedom rigid body which is subjected to hydrostatic, hydrodynamic, and mooring loads. A hydraulic model of the piping network of the malfunctioning pump and the helper pump is proposed. A modified P-controller regulates opening angles of all tank valves for minimal pitch and roll. Two configurations of the floating dock, i. e., a single floating dock and a floating dock with an onboard vessel, are considered. The numerical results show that the optimal helper pumps can be identified regarding the pumps’ total de-ballasting capacity and the dock’s stability. The most severe scenarios can be determined in term of the dock’s maximum draught differences caused by its roll and pitch. The observed maximum draught differences remain small relative to the dock’s width, indicating the effectiveness of employing helper pumps and the proposed automatic ballast control strategy for one-pump malfunction scenarios.

Keywords

Floating dock / Malfunctioning pump / Time-domain simulation / Automatic ballast control / Modified P-controller

References

[1] DNVDNV recommended practice DNV-RP-C205: Environmental conditions and environmental loads. Det norske Veritas, 2012

[2] EurotorcButterfly valve engineering data, 2022

[3] FaltinsenOSea loads on ships and offshore structures, 1993, Cambridge, United Kingdom. Cambridge University Press. 257270

[4] Insurance Marine NewsFloating docks and their operational hazards, 2019

[5] KimeraD, NangoloFN. Predictive maintenance for ballast pumps on ship repair yards via machine learning. Transportation Engineering, 2020, 2100020

[6] MasciolaMMAP++ documentation, 2018

[7] National Transportation Safety BoardDockside capsizing and sinking of towing vessel invader and dry dock #3, 2012

[8] OlsenAN, BringslidMMDanish cantilever dock collapses leaving fishing boat trapped, 2018

[9] RainsfordSRussian aircraft carrier Admiral Kuznetsov damaged by crane, 2018

[10] SchaubH, JunkinsJLAnalytical mechanics of space systems, 2003, Reston, Virginia. American Institute of Aeronautics and Astronautics (AIAA). Inc.. 115158

[11] SchulerMScandlines ferry damaged in shipyard dock accident, 2015

[12] The Maritime Executive2023, 2023

[13] LandowskiGDock with tanker tilts in NAUTA Shipyard, 2017

[14] Retired Felixstowe DockersFloating dock with 2 ships inside broke in two, crane collapsed, ships taking on water, 2019

[15] WenX, García CondeA, ZhangJ, OngMC. Numerical study on the automatic ballast control of a floating dock. ASME 2023 42nd International Conference on Ocean, Offshore and Arctic Engineering, Melbourne, Australia, 86878, 2023

[16] WenX, García CondeA, ZhangJ, OngMC. Dynamic analysis of a floating dock under accidental conditions. Applied Ocean Research, 2024, 144103908

[17] WenX, ZhangJ, García CondeA, OngMC. Numerical study on the automatic ballast control of a floating dock. Journal of Offshore Mechanics and Arctic Engineering, 2023, 1464041401

[18] ZhangJ, LiL, OngMC, EI BeshbichiO, KniatA. Development of a response assessment tool for a floating dock system. ASME 2022 41st International Conference on Ocean, Offshore and Arctic Engineering, Hamburg, Germany, 85901, 2022

[19] ZhangJ, WenX, KniatA, OngMC. A comparative analysis of numerically simulated and experimentally measured static responses of a floating dock. Ships and Offshore Structures, 2024118

[20] ZhangJ, WenX, OngMC. Development of a floating dock numerical model and the ballast water distribution strategy. ASME 2023 42nd International Conference on Ocean, Offshore and Arctic Engineering, Melbourne, Australia, 86878, 2023

[21] ZhangJ, WenX, OngMC. Numerical study on the de-ballasting operation of a floating dock with a malfunctioning pump. IOP Conference Series: Materials Science and Engineering, 2023, 12941012011

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