Project management, engineering and construction company Technip has installed a Sonardyne GyroUSBL transceiver on the stinger of its rigid pipe S-lay and heavy lift construction vessel, G1200.
The transceiver combines a 6G high performance HPT transceiver with a Lodestar Attitude and Heading Reference/Inertial Navigation system in the same assembly.
Alignment errors that are seen in conventional USBL systems can be eliminated with the combination, which is proven to deliver better levels of accuracy and precision.
The new positioning technology is said to improve the quality and accuracy of pipeline touchdown monitoring and is used in conjunction with Sonardyne’s Ranger 2 USBL tracking system.
According to Sonardyne, the technology can track an ROV positioned at pipelay touchdown acoustically to ensure the pipe is being laid in the permitted corridor suitably.
The survey grade USBL acoustic positioning system Ranger 2 has been designed for long range tracking of underwater targets and position referencing for dynamically positioned vessels.
By measuring the range and bearing from a vessel-mounted transceiver to an acoustic transponder fitted to the target, the system calculates the position of a subsea target.
The transceiver is deployed through the hull or over the side of the vessel, typically enabling targets to be tracked below, to the side and far behind.
The system was positioned away from thruster noise and in direct line of sight of the ROV behind it by fitting the transceiver on the end of the G1200’s pipelay stinger, Sonardyne said.
Technip USA subsea intervention manager Iain Miller said: "The success with the stinger-mounted transceiver means that we’re now looking to adopt this novel technique for future pipelay projects here in the Gulf of Mexico and elsewhere."
Sonardyne technical sales manager Ralph Gall said locating a transceiver on the stinger is a solution for ensuring that vessel noise disruption is rejected.
"The time-saving features of the pre-calibrated GyroUSBL also result in reduced operational costs with the ability for users to move it from vessel to vessel with minimal downtime whilst maintaining the highest levels of positioning performance," Gall added.
Image: Sonardyne’s GyroUSBL mounted on the end of the G1200’s 105m long stinger. Photo courtesy of Sonardyne.