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Heavy Equipment
Structural Engineering

Engineering the Integration of a 325t Vertical Lay System on a Multi-Purpose Offshore Vessel

Client Confidential
Year 2023
Platform type
 Tension Leg Platform 
Class
 DNV 1A1, ICE C, SF, COMF-V(3), C(3), HELD-SH, CRANE E0, DYNPOS-AUTRO, NAUT-AW, CLEAN DESIGN, VIBR DK(+), TMON
SOW
 Full engineering support for the installation of a 325t Vertical Lay System (VLS) and auxiliary systems
325t
Total VLS system weight
20
Load cases analysed (static and dynamic)
11
Dedicated work packages (WPs)
100%
Stakeholder coordination completed by GLO Marine
CLIENT CONTEXT
Strategic offshore asset upgrade

The client is a major player in the maritime and offshore industries, with a strong focus on vessel upgrades and retrofits to support offshore energy projects. 

For this particular initiative, the end beneficiary had identified a strategic opportunity to repurpose their offshore asset by installing a high-capacity 325t Vertical Lay System (VLS) on board one of their flagship vessels. 

The VLS was to be integrated above the moonpool, requiring substantial structural, systems, and stability modifications. 

THE CHALLENGE
Complex structural and multidisciplinary integration and equipment integrations

The main engineering challenges were: 

  • Structurally integrating the VLS over the existing moonpool and ensuring it could withstand all operational and survival load conditions. 
  • Modifying and strengthening the hull, decks, and compartments to accommodate new equipment foundations. 
  • Synchronizing multiple disciplines (electrical, structural) while managing client expectations, class approvals, and shipyard constraints. 
THE WORK TO BE DONE
Project phases

GLO Marine was commissioned to carry out the full engineering design and support package for the integration of the VLS, including: 

  • Lay ramp foundations 
  • Moonpool modifications 
  • Carousel loading/Laying hatch 
  • Ancillary equipment foundations 
  • Cooling water system upgrade 
  • Assessment of longitudinal strength 
  • Carrying capacity and stability book update 
  • Statutory and layout drawings 
  • New compartment design for storage winch, spooling tensioner, and control van 
1 / 4

Entire ballast system and ventilation system piping across a tension leg platform.

2 / 4

Ballast system main core inside of technical room of a tension leg platform.

3 / 4

Ballast system main core inside of technical room of a tension leg platform.

4 / 4

Integration of a fully automated ballast system onboard of a tension leg platform.

PROJECT SOLUTION
Steps
01.

Structural and naval architecture analysis

Using both local and global load scenarios (sagging and hogging), our team developed foundation designs for the Lay Ramp and other critical structures.

A total of 20 static and dynamic load cases wereanalyzedfor operating and survival conditions.

02.

We produced full detailed designs and FEAs for: 

  • Lay Ramp hinge foundations (main hinge pins located 1030mm above deck)
  • Moonpool side infills and testing beam support structure
  • Underdeck reinforcement for the carousel hatch
  • Sea fastening and foundations for A&R winch, deflector sheaves, hydraulic power unit, and multiple containers
  • Deck gallery extensions and transformer foundation designs in ROV Winch Rooms
03.

We engineered a full cooling water system upgrade including P&IDs, GA drawings, piping isometrics, and control schematics to support new HPU and electrical equipment loads.  

04.

Our team conducted a comprehensive assessment of the ship’s longitudinal strength. We also delivered updated statutory drawings (GA, fire and safety, docking). 

05.

Our dedicated project lead ensured timely submission of all documentation and seamless handling of Class comments, with zero delays.

END OF DELIVERY
The outcomes
Final results
  • The VLS and all auxiliary systems were successfully integrated on board. 
  • Project delivered within the scheduled time frame. 
  • Optimized foundation and equipment layout reduced yard installation time. 
  • Positive feedback from the client led to a long-term Frame Agreement for future vessel upgrades. 

The vessel was successfully upgraded with a fully integrated 325t VLS system, ready for offshore operations. 

All engineering deliverables were completed on time, Class approvals were secured without delays, and installation time at the yard was minimized. 

Work with us
Contact our retrofit specialist for details
inquiries@glo-marine.com +40746211055
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