With the acquisition of Odim, and new agreements with partners Rolls-Royce has rationalised and expanded its marine crane activities.
The latest developments are in the cranes themselves, with the introduction of the active heave compensated dual draglink crane (DDC) for offshore operations.
The parallelogram linkage formed by the boom and two links allows the hook to be positioned anywhere in a much larger working envelope than the alternative knuckle boom layout.
Other advantages include, increased lifting height with efficient vertical and horizontal load handling. The crane itself has a low centre of gravity and is light for its power and capability.
The first subsea crane of the active heave compensated pedestal dual draglink type is being supplied to Olympic Shipping. It can handle 50tonne loads at an outreach of 8m, or 20tonne on a 20m arm. AHC allows for substantial movements either side of normal.
Using the same design, a dual draglink crane specifically for PSVs is now in service on an advanced UT 754 WP. It runs on a powered trolley mounted on the vesssel’s cargo rail and is able to command the whole of the working deck to lift and position cargo, remotely controlled by the crew.
For vessels that have to use shore bases with restricted access, the crane rated at 10tonnes at 10m can lift cargo over the stern, then move along the rail to spot the cargo on deck.
Knuckleboom and dual draglink designs each have advantages and suit different applications. Both are manufatured and being further developed.