Arc Loading systems

Arc Loading Systems

The HiLoad Arc Loading System (ALS) aims to combine the advantages of tandem and side by side systems in respect to safety and technical robustness. By use of the installed dynamic positioning (DP2) system, the HiLoad LNG can keep the LNGC at a defined safe distance from a cylindrical Sevan FLNG, using reels with cryogenic floating hoses. At the same time, the LNGC is located “down weather”, obtaining significant safety benefits.

The HiLoad Arc Loading System (ALS) consists of three reels with cryogenic floating hoses (20 inches, 20 bar) connected to the LNG hose coupling arrangement on the HiLoad LNG.

A distance of 200 m is selected as the “safe distance” between the cylindrical Sevan FLNG and the LNGC (position of reels) during the LNG offloading operation, with the purpose of keeping the LNGC’s position within the DP operating envelope, using the thrusters and DP system on the HiLoad LNG. The LNGC rudder and main engine in constant “Dead Slow Ahead” mode is used to provide heading control.

The system has a 360 degrees operational area, enabling high offloading availability and FLNG offloading uptime


The overall operation is managed by the Mooring Master located at the LNGC Bridge


The overall operation is managed by the Mooring Master located at the LNGC Bridge

Conventional LNGC's

After the HiLoad is docked onto the LNGC (1-2 nm from the FLNG), the main engine of the LNGC will run in constant power at “Dead Slow Ahead” (typ 40-50 ton forward force)


The Mooring Master will assess the optimal approach heading towards the Sevan FLNG (based on wind, wave and current direction) and set the Autopilot of the LNGC to follow such heading


The DP System on the HiLoad will start positioning the LNGC towards the Sevan FLNG (DP System will take into account the forces applied from the LNGC)

Proven technology

Mooring Master will select optimal location in the Arc (A, B, C…) and the HiLoad DP System will safely position the LNGC to selected position


The Floating LNG Hoses are connected and the LNG Transfer Operation will commence

If the environmental direction is changing (wind, wave or current), a new Autopilot heading may be selected by the Mooring Master and new position selected in the Arc by the HiLoad  Master

LNGC Bow Thruster is kept as back-up heading control

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