BMT was tasked by Wightlink to provide a system that measures the average speeds of their W-class ferries on the Lymington-Yarmouth route.
The system was required to take measurements without compromising the normal operation of the W-class ferries.
The measurements are used by Wightlink to demonstrate that their W-class ferries are complying with the two speed regimes that exist in the Lymington River.
The software solution developed by BMT receives Automatic Identification System (AIS) messages, which are already routinely transmitted by the ferries via VHF radio.
The AIS messages contain a range of information including a unique identification number (the MMSI number of the vessel), position, speed over the ground and course over the ground.
The messages are received using a Commercial Off-The-Shelf (COTS) VHF antenna and AIS receiver which outputs encoded data to a PC via the serial port.
By decoding these messages and extracting the relevant pieces of information, the software developed by BMT is able to calculate the average speed of each ferry and output the measurements to a spreadsheet.
Data is recorded continuously and processed once per day to update the spreadsheet with the previous day’s data.
Live metocean data (including wind speed and direction and tidal state, courtesy of the Channel Coastal Observatory) is also recorded with the speed measurements as these factors can affect the ferries’ speed over the ground.
The software is designed to run automatically without any user input.
However, a simple user interface can be used to control the software. The software is capable of running on any Windows PC (XP or later).
In addition to the software, Wightlink were provided with a report and software user documentation.
For general enquiries relating to Case Study - Wightlink Speed Monitoring Summary, please contact Edward Horabin
BMT Asset Performance