Case Study
Repurposing Pontoons to Create Drydock GC 4500 for Gulf Copper
Client
Gulf Copper
A full service shipyard in Galveston, TX, operating several dry docks of varying sizes from 1,900 LT to 35,000 LT an existing 15,000 LT (Longton) drydock.
Project Overview
Gulf Copper was looking for a dry dock to service 2,500 LT vessels (≈ 200 ft length). Gulf Copper asked Sealy Technical Services (STS):
- To engineer a rightsized drydock designated GC 4500, by repurposing two retired pontoon sections from an older dry dock.
Challenges:
Cost Prohibitive
Operations
Gulf Copper lacked an economical solution for docking 2,500 LT vessels, a very common vessel size along the Gulf Coast.
Aging
Infrastructure
The candidate pontoons had worked as deck barges for years; their wingwalls had been cut away.
Tight
Footprint
New dock had to fit the existing slip and integrate with yard utilities without disrupting current production.
STS Scope of Work
- Evaluate pontoons’ residual strength and define the 4,500 LT lift envelope.
- Engineer new steel wingwalls and internal framing.
- Design a third pontoon to connect the original pontoons.
- Complete scantlings, and provide pump/ballast rooms.
- Generate CAD models for visualization of the new dock and drawings for construction.
Solutions & Innovations
Hydrostatics for new hull geometry
Orca3D model with MS Excel postprocessing for freesurface corrections and shell/bulkhead ΔP envelopes.
Rapid stiffener layout for new wingwalls
Parametric modeling and scripts for autogenerated longitudinal & transverse members; export fed directly to detailing.
Connecting legacy pontoons
Structural and hydrostatic calculations for verify the design of the new middle section.
Certification
The dry dock would need to be designed so that it can be certified in accordance with the USCG requirements for floating steel dry docks.
Results
- The new dry dock became a key tool in the economic success of Gulf Copper.
- Many clients, including several USCG and USACE vessels, have been serviced on the dry dock.
- TMMS now continues to support the operations of this dry dock including USCG inspection and certification on a two-year basis as well as provides docking plans and calculations for all dockings on this dry dock.
Client Testimonial
“STS transformed surplus pontoons into a modern, fitforpurpose drydock. Their modeling accuracy and pragmatic fabrication details let our crews assemble GC 4500 on schedule and under budget. We’re already booking jobs that we previously turned away.”
— Yard Manager, Gulf Copper
Key Takeaway
Reengineering existing assets can unlock substantial CAPEX savings. By combining advanced analysis with rapid BIMdriven detailing, STS delivered a drydock that matches Gulf Copper’s target market, lowers docking costs, and creates a new profit center—all without expanding the yard’s footprint.
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