Practical Aspects of Ride Control Systems for High Speed Ferries

2001 ◽  
Vol 34 (7) ◽  
pp. 485-491
Author(s):  
Alan J Haywood
Keyword(s):  
Control Systems ◽  
High Speed ◽  
Ride Control

Operation of Ride Control Systems to Minimise Slamming of Wave-Piercing Catamarans

2021 ◽  
Vol 163 (A1) ◽  
pp. 29-40
Author(s):  
M R Davis
Keyword(s):  
Control Systems ◽  
High Speed ◽  
Vertical Motion ◽  
Ship Motions ◽  
Wave Surface ◽  
Active Motion ◽  
Ride Control ◽  
Heave Motion ◽  
Control Feedback ◽  
Active Controls

Wave slam produces dynamic loads on the centre bow of wave piercing catamarans that are related to the relative vertical motion of the bow to the encountered wave surface. Rapid slam forces arise when the arch sections between centre bow and main hulls fill with rising water. In this paper time domain solutions for high speed ship motion in waves, including the action of active motion controls, are used to compute the slam forces. Slamming occurs at specific immersions of the bow whilst the peak slam force is characterised by the maximum relative vertical velocity of the bow during bow entry. Vertical motions of bow and encountered wave are in antiphase at encounter frequencies where slamming is most severe. The range of encounter frequencies where slamming occurs increases with wave height. Wave slam loads reduce ship motions, the heave motion being most reduced. Deployment of a fixed, inactive T-foil can reduce slamming loads by up to 65 %. With active controls peak slamming loads on the bow can be reduced by up to 73% and 79% in 4 m and 3 m seas, local control feedback being marginally the most effective mode of control for reduction of slamming.

Recent Developments in Ride Control

2015 ◽  
Author(s):  
Alan J. Haywood ◽  
Benton H. Schaub ◽  
Chris M. Pappas
Keyword(s):  
Control Systems ◽  
High Speed ◽  
New Technologies ◽  
Early Adoption ◽  
Wide Range ◽  
Ride Control ◽  
Recent Developments ◽  
Material Choice ◽  
Maintenance Requirements ◽  
Broad Understanding

The use of ride control systems on high speed vessels has become the norm within many industries, producing better seakeeping that in turn provides a more comfortable and operationally effective vessel. Commercial ferry designers have been at the forefront of adoption of new technologies notably with early adoption of T-foils and interceptors. These devices have been taken up by others, for example offshore crew boats and frontline naval warships. The range of vessel types has also expanded with more industries adopting different hull designs including catamarans and trimarans. Ride control systems have developed alongside innovative designers producing for example combined lifting foil and ride control systems, lifting T-foil systems, retractable T-foils. This paper will review the different ride control devices including fins, trim tabs, interceptors, T-foils (including retractable T-foils) and lifting foils. As well as technical aspects, the discussion will consider costs, ease of installation, operational and maintenance requirements and material choice. Extensive examples from a wide range of industries will be presented. By the end of the talk, delegates will have a broad understanding of the options available to them in improving the seakeeping of their vessels.

RESPONSE OF A HIGH-SPEED WAVE-PIERCING CATAMARAN TO AN ACTIVE RIDE CONTROL SYSTEM

2021 ◽  
Vol 158 (A4) ◽  
Author(s):  
J AlaviMehr ◽  
M R Davis ◽  
J Lavroff ◽  
D S Holloway ◽  
G A Thomas
Keyword(s):  
Control System ◽  
Control Systems ◽  
High Speed ◽  
Control Surface ◽  
Control Algorithms ◽  
Active Centre ◽  
Ride Control ◽  
Control Step ◽  
Set Up ◽  
Ride Control System

Ride control systems on high-seed vessels are an important design features for improving passenger comfort and reducing motion sickness and dynamic structural loads. To investigate the performance of ride control systems a 2.5m catamaran model based on the 112m INCAT catamaran was tested with an active centre bow mounted T-Foil and two active stern mounted trim tabs. The model was set-up for towing tank tests in calm water to measure the motions response to ride control step inputs. Heave and pitch response were measured when the model was excited by deflections of the T-Foil and the stern tab separately. Appropriate combinations of the control surface deflections were then determined to produce pure heave and pure pitch response. This forms the basis for setting the gains of the ride control system to implement different control algorithms in terms of the heave and pitch motions in encountered waves. A two degree of freedom rigid body analysis was undertaken to theoretically evaluate the experimental results and showed close agreement with the tank test responses. This work gives an insight into the motions control response and forms the basis for future investigations of optimal control algorithms.

scholarly journals An experimental investigation on slamming kinematics, impulse and energy transfer for high-speed catamarans equipped with Ride Control Systems

2019 ◽  
Vol 178 ◽  
pp. 410-422 ◽  
Author(s):  
Javad AlaviMehr ◽  
Jason Lavroff ◽  
Michael R. Davis ◽  
Damien S. Holloway ◽  
Giles A. Thomas
Keyword(s):  
Experimental Investigation ◽  
Energy Transfer ◽  
Control Systems ◽  
High Speed ◽  
Ride Control

Measured Loading Response of Model Motion Control Stern Tabs

2013 ◽  
Vol 155 (A1) ◽  
Keyword(s):  
Control Systems ◽  
Motion Control ◽  
High Speed ◽  
Lift Force ◽  
Lift Coefficient ◽  
Test Apparatus ◽  
Circulating Water ◽  
Ride Control ◽  
Hydraulics Laboratory ◽  
The University

Active trim tabs are commonly used as part of the ride control systems of high-speed craft. This paper investigates the lift characteristics of rectangular stern tabs that are commonly fitted to INCAT wave-piercer catamarans. A test apparatus was developed to enable the testing of a model scale trim tab in a circulating water tunnel in the University of Tasmania hydraulics laboratory. The magnitude and location of the lift force produced by the tab were measured over a range of tab angles and flow velocities. From this the lift coefficient of the tab was calculated and the performance of the tab under varying conditions was analysed. The lift force produced by the tab was shown to increase with velocity and tab angle as expected, with the lift coefficient of the tab increasing linearly with tab angle and remaining relatively constant with increases in flow velocity. The magnitude of the measured lift coefficient was lower than had been previously estimated in shallow water tests and the force was found to act forward of the tab hinge, indicating that much of the lift force generated by the tab is due to the increased pressure on the underside of the hull forward of the tab.

MEASURED LOADING RESPONSE OF MODEL MOTION CONTROL STERN TABS

2021 ◽  
Vol 155 (A1) ◽  
Author(s):  
J Bell ◽  
T Arnold ◽  
J Lavroff ◽  
M R Davis
Keyword(s):  
Control Systems ◽  
Motion Control ◽  
High Speed ◽  
Lift Force ◽  
Lift Coefficient ◽  
Test Apparatus ◽  
Circulating Water ◽  
Ride Control ◽  
Hydraulics Laboratory ◽  
The University

Active trim tabs are commonly used as part of the ride control systems of high-speed craft. This paper investigates the lift characteristics of rectangular stern tabs that are commonly fitted to INCAT wave-piercer catamarans. A test apparatus was developed to enable the testing of a model scale trim tab in a circulating water tunnel in the University of Tasmania hydraulics laboratory. The magnitude and location of the lift force produced by the tab were measured over a range of tab angles and flow velocities. From this the lift coefficient of the tab was calculated and the performance of the tab under varying conditions was analysed. The lift force produced by the tab was shown to increase with velocity and tab angle as expected, with the lift coefficient of the tab increasing linearly with tab angle and remaining relatively constant with increases in flow velocity. The magnitude of the measured lift coefficient was lower than had been previously estimated in shallow water tests and the force was found to act forward of the tab hinge, indicating that much of the lift force generated by the tab is due to the increased pressure on the underside of the hull forward of the tab.

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