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The 2019 Vice Admiral E. L. Cochrane Award: Slam loads and kinematics of wave-piercing catamarans during bow entry events in head seas

Citation

Shabani, B and Lavroff, J and Davis, MR and Holloway, DS and Thomas, GA, The 2019 Vice Admiral E. L. Cochrane Award: Slam loads and kinematics of wave-piercing catamarans during bow entry events in head seas, Journal of Ship Research, The Society of Naval Architects and Marine Engineers, 62, 3, pp. 134 - 155. (2018) [Award]


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Abstract

Centre bow (CB) design for wave-piercing catamarans (WPCs) is a critical compromise between minimization of slamming and protection against deck diving. To inform the design process, this article investigates the slam loads and kinematics during bow entry events in regular head seas for a 112-m WPC with systematic variations to its CB and wet-deck geometry. Model tests using a 2.5-m hydroelastic segmented catamaran considered five different CB configurations, designated as the parent, high, low, long, and short CB. The results indicated that changes in the CB length had little effect on the general kinematic trends obtained for the pitch, heave, and bow vertical displacement at the instant of slamming, but increasing the wet-deck height resulted in an increase in heave (but not pitch) at slamming. Two new design ratios are proposed. The CB immersion depth to arch height ratio showed slamming occurring in the range of 0.3-0.6 depending on the wave encounter frequency and the CB configuration. The CB buoyancy in the encountered waves was estimated by considering both immersion depth and area along the CB in waves through relative motion analyses. It was found that the buoyancy to slam force ratio increased with increasing wet-deck height but not with increasing CB length. This suggests that an optimal CB configuration could be achieved by first modifying the arched cross-structure to reduce the arch filling effect on slamming severity and then maximizing the CB buoyancy to slam force ratio by increasing either the wet-deck height or the CB length.

Item Details

Item Type:Award
Keywords:wave-piercing catamaran, hydroelastic segmented model, centre bow, relative motions, slamming, vertical bending moments
Research Division:Engineering
Research Group:Maritime engineering
Research Field:Ship and platform structures (incl. maritime hydrodynamics)
Objective Division:Transport
Objective Group:Water transport
Objective Field:Domestic passenger water transport (e.g. ferries)
UTAS Author:Shabani, B (Dr Babak Shabani)
UTAS Author:Lavroff, J (Dr Jason Ali-Lavroff)
UTAS Author:Davis, MR (Professor Michael Davis)
UTAS Author:Holloway, DS (Associate Professor Damien Holloway)
ID Code:141485
Year Published:2018
Deposited By:Engineering
Deposited On:2020-10-22
Last Modified:2020-12-21
Downloads:0

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