Case Study

Stena IceMAX

Stena Drilling

Stena Icemax Drillship, Astican Shipyard


The Stena IceMax is a 6th generation DP3 Drillship. One of four similar vessels owned and operated by Stena Drilling. The vessel required a Special Periodic Survey (SPS) in accordance with DNV standards. The project was completed as part of a yard stay in Las Palmas in the Canary Islands.

AquaTerra personnel conducting a special periodic survey working at height on the Stena IceMAX
The Challenge

The entire shipyard stay was planned for a 55 day program in order for the vessel to leave on time for its next drilling campaign. This would require multiple simultaneous work scopes to meet the schedule.

The client workscope required a large volume of heavy hydraulic equipment to be removed early in the project schedule in order for it be transferred to the workshop, overhauled and re-installed.

Removal and overhaul of Main Well & Aux Well Sheave Clusters would require the use of a large quayside crane in order to remove both to quayside for overhaul.

A high volume of complex rigging operations would be required to remove Boom & Knuckle cylinders on both Stb Fwd & Stb Aft Knuckle Boom Cranes (KBC).

Key Summary
  • Special Periodic Survey carried out in accordance with DNV onboard a 6th Generation Drill Ship
  • Comprehensive NDT, Inspection and Rigging work scopes
  • Inspection of vessel critical structure using conventional and advanced NDT methods
  • DROPS survey / corrective action completed throughout vessel upon completion of all construction scopes ready for vessel departure
  • Provision of 15 man specialist rigging and hydraulic team and 6 man inspection team
  • Lift planning and supply of lifting equipment for all work scopes by AquaTerra
  • Strip down, removal replacement of Main Well (52t) and Aux Well Sheave (45t) cluster by Quayside crane, Change out of KBC Boom & Knuckle Cylinders on Stb Fwd & Stb Aft Cranes Divertor valves, drill floor equipment and work baskets
  • In situ maintenance of various equipment including MW & AW Hydrarackers, MW & AW Tubular Chutes, Choke Manifold, N-Line Tensioners
  • Inspection programme utilised a range of non-destructive testing (NDT) techniques including Ultrasonic Testing, MPI and Eddy Current.

Role, Co.

The Solution

AquaTerra mobilised an experienced rope access multi-discipline team to execute all NDT and rigging work scopes.

The work packs and lift plans for all the heavy lifting work scopes were produced by AquaTerra in advance of the execution phase. This meant all equipment could be sourced and mobilised in advance of the yard stay and was ready and waiting for the vessel to arrive.

Key project and supervisory personnel were mobilised to the vessel prior to the transit into the yard in order to assess all worksites, prepare all work permits and risk assessments.

Advanced NDT technique phased array utilised to reduce the schedule for some of the KBC Cylinder Pins, TDS Pins, N-Line Tensioners hang off pins, plus many others on a variety of equipment.

In order to gain class approval for all inspection activities, AquaTerra worked very closely with the Stena Rig superintendent and the DNV surveyor throughout the project.

The Result

The work was executed within the 55 day schedule with no LTI’s or First Aid cases, and additional work scopes were completed due to time saved on critical path work scopes. All inspection activities were completed and reported on site, with a comprehensive inspection package handed over prior to departure.

The main critical path workscope to remove, overhaul and replace the Main Well & Aux Well Sheave Clusters was completed ahead of schedule which allowed the quayside crane to be released earlier. Class approval for all Inspection activities was granted.

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