Subsea technology company Seatools has completed the development, manufacturing and testing of a plough position monitoring buoy for Boskalis.
Following sea trials, the buoy has been fitted onto a subsea plough for a subsea cable route clearance project.
Whereas USBL is the conventional way to determine the position of subsea vehicles, this acoustic method fails to function properly for towed vehicles that operate in shallow waters with much ambient noise, such as thruster wash, Seatools explains.
Therefore, Boskalis developed a buoy-based monitoring method that monitors the position of its subsea ploughs and boulder clearance tools.
The monitoring buoy connects to the towed vehicle by means of a steel cable. As soon as the vehicle is placed on the seafloor, the buoy is floated.
By combining multiple, real-time data, including winch paid out wire length measurement Rovins data, and DGPS data, the position of the plough can be accurately determined in all three dimensions.
The buoy also features an integrated subsea winch, making it fully retractable when launching and recovering the towed vehicle.
While Boskalis was responsible for the fundamental concept and operational procedures, Seatools brought the concept alive.
Specifically, Seatools took care of concept engineering, detailed engineering, as well as the manufacturing and factory testing.
Boskalis and Seatools collaborated on predicting and adjusting the desired hydrodynamic behaviour of the 8-meters high buoy.
They used the hydrodynamic simulations for the behavior of the buoy under even the most testing of weather and operational conditions.
This also included the launch and recovery from the subsea vehicle.
Seatools managing director, Jan Frumau, said:
“In close cooperation with Boskalis, we realised a really unique piece of high-tech subsea equipment. We strongly believe in the added value of such a collaboration, where clients bring in a concept or core technology and ask Seatools to bring the concept alive.”