The Isle of Man Steam Packet Company has acquired a new ferry, Manxman, to operate between Douglas (Isle of Man) and the United Kingdom (Heysham and Liverpool).

Manxman ferry during sea trials.

This new ship replaces the company’s current conventional ferry, Ben-my-Chree. The Manxman has a length overall of 133 metres, which makes it a bigger vessel than the ship currently operating along the same line.

Steam Packet was interested in investigating the new manoeuvring strategy to access the above-mentioned ports with this newbuilt vessel and train their captains using all the manoeuvring means that this vessel has available.

MARIN has followed an integral approach, combining experimental and numerical worlds by performing captive manoeuvring model tests to derive a high-fidelity simulation model which could be used for training, familiarisation and assessment purposes. This simulation model was then used in our Full Mission Bridge Simulator by the Manxman’s captains to understand the manoeuvring behaviour of the vessel while accessing the ports under local environmental conditions.

Integrated approach

This integrated approach consisted of several steps. In the first step input data to derive a simulator model of the Manxman vessel was collected. To do so, dynamic captive manoeuvring tests were carried out in the Offshore Basin using a 6-metre-long wooden scaled model of the ship.

Captive manoeuvring model tests measure the ship’s hydrodynamic loads under a broad range of imposed motions in a fully controlled environment. The model of the Manxman was fixed to the carriage of MARIN’s Offshore Basin, which imposed predefined motions and actuator controls. While the carriage pulled the ship model along a given track, the manoeuvring loads applied to the ship and its actuators were recorded. The model was heavily instrumented, with more than 25 force transducers, several potentiometers, servos and electrical motors.

Manxman model in the Offshore Basin during captive model tests.

Model tests in shallow and deep water

The flexibility and size of the Offshore Basin (40m x 40m) enabled a wide variety of imposed motions, actuator controls and sailing conditions. Thanks to a computerised planar motion carriage, any planar motion can be prescribed to the ship model. In addition, the Offshore Basin features a rigid concrete floor that can be moved up and down due to large pistons, enabling tests in shallow waters, as well as in deep water. The tests in shallow water provided insights to better capture shallow water effects in harbour conditions, where the bathymetry is always restricted.

Captain during an approach manoeuvre at the Full Mission Bridge Simulator.

Bird’s eye view from an approach manoeuvre at Douglas port.

Track plot of an approach manoeuvre at Douglas port.

Following the dedicated model tests, MARIN analysed the results to create a high-fidelity simulation model. Unlike traditional approaches based on generic coefficients, this model was fully tailored to the Manxman ferry. As such, it was based on the actual geometry of the ship and appendages, using MARIN’s expertise and cutting-edge technology.

Simulations on the Full Mission Bridge

Finally, simulations were carried out on MARIN’s Full Mission Bridge. This facility has a 360°-degree projected outside view. The FMB1 has a vertical projection on the port and starboard side of the bridge showing the view from the bridge wing down along the vessel when switching to the bridge wing view.

Metocean conditions in the approaches and the ports were realistically included in the simulations. Wind was uniformly modelled for most of the area and shielding from other vessels (moored or sailing) or by buildings and other constructions, such as terminals, was also accounted for. Temporal variations due to gusting are a standard feature. Tidal information about water levels and current patterns were included for a full tidal cycle.

Andy Atkinson

Senior Captain Manxman

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