New articulating a-frame by MacArtney a time-saving innovation

a-frame lars MERMAC

To make A-frame adjusting and equipment change faster, easier and safer, MacArtney has designed and developed a new and unique A-frame system.

Reducing equipment changeover and adjustment time
A-frames installed along the side or at the rear of vessels are used for launching a wide range of equipment and often for several tasks during a voyage. Dismounting equipment, adjusting the A-frame for a new task and mounting new equipment can be a time consuming and often complex task.

Equipment can be large and heavy and the A-frame often needs adjusting for different equipment, requiring a technician being raised up to the top bar of the A-frame. Operators often have to be hoisted up in a chair or a harness up to 3 to 4 metres to reach the top, making adjustments time-consuming - and because of the potential hazards in working at height on a moving vessel, such work involves a number of safety precaution procedures.

MacArtney has designed and built a new kind of A-frame that makes accessing equipment on the A-frame more convenient and safer for personnel. This new system makes it possible to access the top of the A-frame from the deck of the ship.
This clever hydraulic design, using just 2 rams, articulates the A-frame a full 149° from the 20° angle for launching equipment over the side or the rear of the vessel to 11° over the deck of the vessel. It has a high total safe working load of 89 kN throughout the entire process.


Innovation gives 149 degree range of movement
Equipment, for example a full ROV launch system, can be installed on the A-frame on deck by operators working at deck level and readied for launch.

With all operators clear of the frame, the A-frame can be lifted up, past 90° and then onwards over the side or the rear of the vessel and lowered down to 20° for launch into the water. For retrieval, the process is reversed and the A-frame raised past the 90° point and lowered to 11° over the vessel deck.
From here, operators can conveniently remove and replace equipment and make any necessary adjustments to the A-frame without having to be hoisted up the frame.

Lowering the A-frame to 11° from the deck also makes any service and maintenance work easier and faster to perform.

System facts
MacArtney’s Articulating A-frame is designed with a safe working load of 89 kNand safety factor (Psi) of 2.5. Luffing is at 48.5 kN with docking head and 89 kN without docking head. It has a luffing range of 11 degrees inboard to 20 degrees outboard.


See the system in action during testing here:


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