MacGregor Advances Floating-to-Floating Transfer and LCO2 Systems

MacGregor has expanded its offshore technology portfolio with a certified floating-to-floating personnel transfer capability for its Horizon gangway and a new bow transfer system designed for direct ship-to-well transfer of LCO2.

The Horizon gangway has received DNV certification under DNV-ST-0358 for floating-to-floating personnel transfers following a successful sea acceptance test. The certification enables motion-compensated connections between two vessels moving independently, allowing personnel to transfer between floating assets without a fixed landing point.

The capability is designed for applications including FPSOs, floating rigs, floating wind arrays and offshore service fleets. It can allow crew changes and service operations to be carried out at sea rather than being scheduled around port calls.

The system uses a purpose-designed flap at the gangway tip instead of the conventional docking head used for fixed structures. LiDAR-based relative-motion tracking provides real-time input to the gangway's motion-compensation system to maintain the connection as both vessels move.

Floating-to-floating capability is an extension of MacGregor's existing Horizon gangway family and can be retrofitted or upgraded on units already in operation.

Separately, MacGregor has developed a Liquid Carbon Dioxide (LCO2) Bow Transfer System (BTS) designed to enable direct ship-to-well and ship-to-rig transfer of LCO2 between carriers and offshore injection facilities.

The system is intended to connect capture plants directly with offshore injection units, potentially removing the need for intermediate onshore storage and conditioning facilities.

BTS connection phase view inside LCO2 carrier (Credit: MacGregor)

The BTS builds on MacGregor's Bow Loading System technology, which has been used in the oil and gas sector since the 1970s. The company says about 79% of the new system is based on field-proven technology, with the remainder comprising modifications and newly engineered components for LCO2 handling.

Seal materials have been tested with SINTEF under rapid gas decompression and LCO2 conditions. The system is designed to maintain integrity through repeated pressure cycles and temperatures as low as minus 57°C, while supporting operations in sea states with wave heights of five to six meters and water depths of up to 150 meters.

MacGregor's LCO2 transfer hardware is designed as the basis for four system architectures covering low- and medium-pressure operations at 30-60 bar and high-pressure operations at 300 bar, including direct reservoir injection through seabed swivels or disconnectable turrets.

MacGregor joined the EU-funded COREu research and innovation consortium in early 2025 and is undergoing technology qualification with DNV. The qualification process has completed its planning phase, covering the qualification basis, technology and threat assessments and qualification plan, with prototype testing and demonstration expected in mid-2027.