Influence of an active T-foil on motions and passenger comfort of a large high-speed wave-piercing catamaran based on sea trials

Giles Thomas,Chun-Yu Lau,Jason Ali-Lavroff,Javad A Mehr,Damien S Holloway,Babak Shabani

doi:10.1007/s00773-022-00876-8

Abstract

T-foil and stern tabs were installed on a wave-piercing catamaran (Incat Tasmania Hull 061) to improve ship motions and passenger comfort. More than 40 total effective hours of sea trials were conducted by the US Navy in 2004, encountering sea states 4–5 in the Atlantic Ocean near the United Kingdom. In this paper the influence of a ride-control system (RCS) on the heave and pitch response amplitude operator (RAO) of the full-scale high-speed catamaran was investigated using the sea trial data. The reduction in motion sickness incidence (MSI) was estimated in order to examine the effectiveness of the RCS in improving passenger comfort. With the existing control algorithm, the vertical accelerations were found to be best controlled by the active T-foil working together with the active stern tabs, while the pitch RAO was mainly mitigated by deploying only the stern tabs. About a 23% reduction was observed in the peak heave RAO with deployment of an active T-foil. The MSI can be reduced by up to 23% with respect to the cases with stern tabs only, depending on the encountered wave conditions, based on ISO recommendation for MSI calculation of a 2-h seaway passage.

Highlights

Introduction1.1 BackgroundRoll-on–roll-off (Ro–Ro) vessels have an important role in maritime transportation due to their ability to carry large number of passengers, cargo, and vehicles
The authors found that in most cases, the estimates of the conventional strip theory were aligned well with the measured results. Their analysis extended to the prediction of Motion Sickness Incidence (MSI) and operability envelopes based on the seasonal wave scatter diagrams
A phase lag was noticed between waves at the bow and motion at the Longitudinal Centre of Gravity (LCG), but since the motion analysis in this study focuses on comparing the real part of the fast Fourier transform (FFT), the phase shift due to wave measurement location makes no difference

Summary

Introduction

1.1 BackgroundRoll-on–roll-off (Ro–Ro) vessels have an important role in maritime transportation due to their ability to carry large number of passengers, cargo, and vehicles. Tezdogan et al [6] used three different numerical methods, namely conventional strip theory, high-speed theory without hull interaction, and high-speed with hull interaction, to generate RAOs and analyse vessel operability. These numerical results were compared to the experimental data collected from a 151 m Ro–Ro catamaran ferry travelling at 20 knots. The authors found that in most cases, the estimates of the conventional strip theory were aligned well with the measured results Their analysis extended to the prediction of Motion Sickness Incidence (MSI) and operability envelopes based on the seasonal wave scatter diagrams

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Results

Conclusion