In 2016, ALATAS completed a full refurbishment and upgrade work scope on a Landel Inc. 20 ton pipe handling gantry crane aboard a DNV GL class semi-submersible drilling vessel.
The gantry crane is in standard configuration with long travel movement over the length of the drilling storage and laydown space on runway beams mounted to the vessel superstructure. Cross travel movement of the trolley system uses a twin bridge girder beam. The crane operates with a failsafe electro-magnet grab system to carry drill pipe from the storage and laydown area through to the drill floor. The grab system utilises permanent magnets fitted with field coils which release payload with a reverse magnetic flux field initiated by the crane operator. Crane movements are made by operator controls in a cab mounted at the end of the bridge beam section.
The gantry crane was commissioned in 1985 with its functional specification developed with a now superseded DNV class regulation. Our client had received a charter which stipulated the crane be upgrade for several reasons; the original crane was operating well beyond its design lifetime and was obsolete with spare parts no longer available.
Alatas developed an upgrade solution to bring the crane into compliance with current DNV GL class certification requirements. This upgrade utilised the existing main structural steel elements and incorporated bespoke engineered solutions to bring the system into compliance. Work was completed over 49 days with the vessel berthed in Ølensvåg Norway.
The upgrade package consisted of the following:
Electrical power distribution and control systems.
Twin hydraulic power pack.
Hoist brake upgrade.
Hoist line out encoders.
Long and cross travel drive systems.
Long travel rack gears for drive systems.
Throughout the detail engineering phase Alatas engineers in various regional offices engaged the client, DNV GL, and suppliers to develop a robust and cost-effective solution. Engineering support including drafting, calculation and procedures was supplied by Alatas Crane Services UK and Alatas Crane Design in Austria throughout the build phase. Alatas provided multi-disciplined service technicians and on-site project engineering management throughout the build. Logistics and material support functions were carried out by shipyard personnel and third party contractors.
The design dossier was submitted to DNV GL for design review and was passed in the first iteration. In the final phase of the project the FAT, load test and final function check were witnessed and authorised by DNV GL and the client. The as-built commissioning manual, inspection test plan, user manual, parts and service manuals were submitted to the client and DNV GL at project conclusion.