BP Ampelmann Support Structure

March 2021



Structural Steelwork & Fabrication

Dales Marine Services Ltd were contracted to fabricate and install a support structure (2 no.) for the Ampelmann Gangway System on board a Platform Supply Vessel. The contract was to have fabrication complete in 4 weeks and 7 days for installation and commissioning of system. This was achieved with no delays to project schedule.

The support structures total weight (2 parts) was 46te and when constructed was 10m wide x 10m long and 10.7m tall. The unit’s construction also meant that it could not be moved by any road transport and had to be assembled on quayside for loading out.


  • 46te of Steel Box, Circular Hollow and Universal Column Ordered within UK.
  • All supplied in S355J2 Grade Materials.
  • Delivered within 5 days of order.
  • Dales provided the supplier with a cutting list so all steel was supplied cut to length in order to save time during fabrication.


  • Dales fabricated the 2 structures in 3 weeks using our 24/7 availability.
  • Holds and Inspections carried out to IT&P with clients QA Team.
  • All welding connections were full penetration with 100% UT Inspection.
  • Fabricated in our workshop in sections and shipped to quayside for assembly. Sections: Base platform and 4 no. leg sections, walkways and stairs.
  • Fully assembled and tested on quayside
  • Using 2 cranes and a tandem lift we turned the structure for final fit out and trial fit.
  • Scaffolding erected over structures areas to provide safe access to fit gratings.
  • Full structure was completed and ready to install within 4 weeks.


  • Within 7 days we mobilised the foundation steelwork to support the Ampelmann Struc-ture, the Ampelmann Unit, power units and control cabins for gangway system, accom-modation modules and FRC Unit.
  • Reinforcement of underdeck structure was required.
  • Contract lift operation carried out to load 40te Gangway system.
  • Securing of all systems and commissioning.
  • All carried out to DNV specifications and inspections.


  • After 6 months we demobbed vessel and reinstated deck to pre-mob condition.
  • Storage of support structure remains across from Quayside with specialised transport required.

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