Ship Motion Measurement
Accurate registrations of ship's sailing to Belgian harbours
Since the beginning of 2010 Flanders Hydraulics Research possesses an accurate measurement equipment that can be installed in a short time on almost any vessel. FHR aims to apply this new feature for validation of mathematical manoeuvring models present in their ship manoeuvring simulators. For this purpose two surveys already took place.
Measurement equipment
The equipment uses a combination of RTK GPS antennas, accelerometers and inclinometers to measure the position and orientation of the vessel in three dimensions with an accuracy upto respectively 2 cm and 0.01°. It consists of a precalibrated housing carrying two GPS antennas with seperation distance two metre, sending the measured data wireless to a laptop standing in the bridge house. Furthermore AIS-data from the ship's pilot plug are supplied to the laptop using a pilot plug splitter. During the survey the time evolution of rudder angles and machine orders are registrated manually.
Survey 1: Rolling of a PCC
The objective of the first survey was the evaluation of the roll-motion on an outbound Pure Car Carrier sailing from the left bank of the port of Antwerp to Flushing. The survey resulted in valuable information regarding the correlation of rudder angle, ship speed, yaw velocity and roll angle.
Survey 2: Lock effects on a bulk carrier
During a second survey, carried out just recently, a Kamsarmax bulk carrier with a breadth of 37 m was followed entering the Westlock in Terneuzen characterised by a total breadth of 40 m and an available breadth of 38 m (due to the fendering system). As one can imagine this manoeuvre results in large lock effects when the ship presses the water out of the lock between the small gaps between the ship and the lock structure.
The entrance of Kansarmax bulkcarriers to the West lock in Terneuzen was simulated at FHR in 2007 for determining the maximum ship dimensions to whom the West lock is limited. The survey supplies FHR with validation data for the mathematical model of lock effects present in the ship manoeuvring simulators.
