Design Portfolio

The Autonomous Underwater Vehicle is intended for underwater survey missions with an endurance of up to 30 days. The dimensions of the AUV are Length - 10 m, Diameter - 2 m and a displacement of 20 Tons.

Engineering the Future of Subsea Robotics

Designing the pressure hull of a 12metre, 20ton Autonomous Underwater Vehicle (AUV) is a challenge that blends hydrodynamics, structural engineering, and precision manufacturing. For an Indian customer developing advanced subsea robotics, CMarine delivered a complete productionready design package for this missioncritical asset.

The pressure hull - the core of any deepdiving AUV - required a carefully engineered platebending strategy to achieve the required strength and watertight integrity. Our team developed a manufacturingoriented design, ensuring that each curved plate could be formed accurately and economically.

We also designed:

• Equipment foundations for onboard electronics, propulsion, and navigation systems
• Penetrations and interfaces for sensors, connectors, and control systems
• A complete welding schedule, ensuring structural integrity under extreme underwater pressures
• A detailed fitup plan to streamline assembly
• A comprehensive Quality Assurance Protocol (QAP) to guide inspection and testing

The result was a robust, productionready AUV structure engineered for reliability, safety, and longterm subsea performance.

Solan Field Subsea Oil Storage Tank (SOST) by Atkins

The underwater oil storage facility is intended for temporary storage of crude oil extracted from the wells on the ocean bed. The crude thus stored will be evacuated to vessels to be carried for refinement on shore.

• Overview & Purpose
  Located ~300 m from the platform at 135 m water depth in the UK North Sea, the SOST is a steel subsea storage tank used for temporary crude storage where pipelines or FPSOs are unviable.
• Design & Capacity
  • Holds ~300,000 barrels of stabilized oil
  • Dimensions: ~45 m × 45 m × 25 m
  • In-air weight: ~10,100 tonnes
  • Construction & Installation
  • Fabricated in dry dock in Dubai per Atkins’ design
  • Weighed-down, gravity-set on seabed
  • Multiple compartments for oil discharge and interface control
• Oil-Water Interface Management
  • Employs hydrostatic displacement; seawater injected from topside pushes oil upward to shuttle tankers
  • Features a single-anchor loading system with seabed hose-picked up via pennant line
• Automation & Monitoring
  • Full remote control from shore (Aberdeen)
  • Innovative internal architecture for corrosion monitoring, subsea inspection access, and interface management.

Structural and Environmental Design Considerations

• Hull & Material Engineering
  • Massive steel shell incorporates internal stiffening for hydrostatic load resistance
  • Multi-cellular layout adds robustness and optimizes oil-water separation
• Thermal Management
  • Deep-water tanks face significant heat loss-studies (e.g., SPIE, 2025) show uninsulated tanks (e.g., 10,000 m³) can drop oil temperature from 40 °C to near ambient within 24 hours
  • Insulation (~100 mm) is effective, retaining ~35 °C over 7 days-meets standards such as GB/T 4272-2024 (~52 W/m² max heat flux)
• Buoyancy and Ballasting
  • Utilizes gravity anchoring with wet weight
  • Corrosion Protection & Inspection
  • Corrosion systems include coatings, cathodic protection, and internal monitoring sensors
  • Regular subsea maintenance and surveying ensures integrity over life-cycle

Heavy Engineering for Subsea Infrastructure

CMarine was commissioned to design the structure of an underwater oil storage tank intended for installation at a depth of 50 metres. This was no ordinary tank - it required a heavy grilled steel structure capable of withstanding hydrostatic pressure, operational loads, and longterm subsea exposure.

The design involved:

• Thick steel plates and heavy sections
• Large structural panels requiring lifting analysis to ensure safe handling during fabrication and installation
• A complete 3D structural model to eliminate clashes and ensure dimensional accuracy

Because the entire structure was subject to 100% Xray radiography, our production drawings had to be exceptionally precise. Weld preparations, joint details, and inspection points were meticulously documented to support flawless fabrication.

This project showcased CMarine’s ability to deliver highintegrity subsea structures where safety and reliability are nonnegotiable.

Vessel Background
The FPSO Frade, converted from the tanker Universe Frontier, was outfitted to handle approximately 100,000 barrels per day of oil treatment, compress 106 million scf/d of gas, and inject 150,000 barrels of water daily.

Scope of Work at Drydocks World

• Acting as subcontractor to DDW, C-Marine performed comprehensive engineering drawing preparation work for Piping, HVAC and Electrical and instrumentation systems on the topsides.
• This included high-pressure stainless-steel tubing (up to 1″ diameter), hydraulic lines, and electrical terminations.

Timeline & Location
These activities took place in Dubai, likely around 2006-2008 during the main conversion of the vessel into FPSO Frade.

TI ASIA Conversion to FSO “ASIA”

• Vessel & Assignment
  • TI ASIA is one of the four ULCC (Ultra Large Crude Carrier) “TI class” supertankers, originally built in 2002-2003.
  • At Drydocks World, it underwent a conversion to become the FSO ASIA, a Floating Storage and Offloading unit.
• Scope of Work
  • Installation of new import/export manifold and piping systems.
  • Added pipe racks, heaters, VOC (volatile organic compound) units, metering skids, and separation units on the main deck forward.

Drydock Facilities & Yard Enhancements

• Berth Capacity Expansion
  • In May 2009, Drydocks World opened Berths 9 and 10 to accommodate ultra-large vessels including TI ASIA.
  • These berths are each ~59 m wide with dredged depths of ~11 m, tailored for VLCC/ULCC conversion, FPSO, and FSO projects.
• Strategic Significance
  • The TI ASIA conversion exemplified DDW’s advanced capacity and technical proficiency in handling massive tanker-to-FSO transformations.

Transforming Tankers into Offshore Production Assets

Floating Production Storage and Offloading units (FPSOs) are the backbone of offshore oil production, and many are created by converting aging tankers with structurally sound hulls. CMarine played a key role in one such conversion project at Drydocks World (DDW), Dubai.

A dedicated team of CMarine engineers spent eight months onsite, working closely with the yard to deliver:

• A complete hull structural model
• Detailed piping design for topside and hull systems
• Electrical cabling layouts and routing
• Accurate BOMs for steel, piping, and electrical systems

FPSO conversions demand deep understanding of both shipbuilding and offshore production requirements. Our integrated design approach ensured that the converted vessel met stringent safety, operational, and classification standards.

Know More

DolWin Beta HVDC Converter Platform (North Sea)

• C-Marine played a role in preparing the engineering drawings as a sub-contractor to Drydocks World.
• Drydocks World built the DolWin Beta offshore converter platform-at the time, the world’s largest HVDC platform-for the DolWin2 project connecting German wind farms.
• The complex steel structure weighed ~23,000 tonnes and measured about 100 m long, 70 m wide, and 90 m tall-sufficient steel to build two Eiffel Towers.
• ABB held overall electrical contract responsibility, providing its HVDC Light® converters and cable technologies, while Aibel designed the platform and Drydocks World executed full fabrication and outfitting.
• After fabrication, the platform was transported to Norway for final outfitting and then installed offshore in mid-2015. The project was officially handed over in 2017.

Continuing Expertise: Multiple HVDC/HVAC Platforms

• Drydocks World has delivered two HVDC and two HVAC platforms in the North Sea-including DolWin2, BorWin3, and the Hollandse Kust Zuid Alpha & Beta projects-working under ABB electrical scope.
• This track record showcases their capabilities in handling large offshore modules containing high-voltage converter systems, switchgear, and control equipment.

Key Takeaways

• Drydocks World provides comprehensive EPCI services (Engineering, Procurement, Construction, Integration), delivering platforms outfitted with ABB’s high-voltage converter systems.
• They have successfully executed record-breaking offshore structures like DolWin Beta, demonstrating strong expertise in mechanical fabrication, module integration, logistics, and interface with ABB’s electrical technology.

Engineering the Giants of Offshore Wind

High Voltage Direct Current (HVDC) platforms are among the largest floating structures in the offshore energy sector. They house the power conversion equipment that transmits electricity from offshore wind farms to the mainland. CMarine contributed to the detailed design of one such structural giant.

With panel sizes reaching 25 m × 12 m, the platform demanded a robust structural model capable of supporting heavy ABB power equipment. Our team delivered:

• A complete steel structural model
• Accurate Steel BOM
• Detailed routing of piping, cabling, and HVAC ducts
• Extraction of all associated BOMs

The scale of these platforms required meticulous planning and coordination. CMarine’s design ensured structural stability, ease of fabrication, and seamless integration of electrical and mechanical systems.

• Jaya Shipbuilding, a well-known Singapore-based yard, specialized in building offshore support vessels including PSVs, AHTS (Anchor Handling Tug Supply), and utility vessels. M/s Jaya Shipbuilding contracted C-Marine to carry out the detailed design of 02 PSVs during 2014.
• Jaya constructed two PSVs designed for offshore oil & gas field support-transporting drilling fluids, fuel, water, and equipment between shore bases and offshore rigs.

Design & Specifications

• Type: Platform Supply Vessel (DP2 class for dynamic positioning).
• Length: ~75-80 meters.
• Deck Area: Large open deck for cargo and tubulars.
• Cargo Capacities:
  • Dry bulk tanks for cement/barite.
  • Liquid tanks for drilling mud, brine, and fuel.
• Propulsion: Diesel-electric or conventional twin-screw propulsion with bow thrusters for station-keeping.
• Safety & Compliance: Built to ABS or DNV class standards, with SOLAS compliance for offshore operations.

Construction at Jaya Shipbuilding

• Hull and superstructure fabricated at Jaya’s Batam and Singapore facilities.
• Outfitting included cargo handling systems, DP systems, and accommodation blocks for ~40-50 crew.
• Delivered as part of Jaya’s fleet expansion program targeting Asia-Pacific offshore markets.

Acquisition by Mermaid Marine Offshore (Australia)

• In 2014, Mermaid Marine Australia (MMA) acquired Jaya Holdings, including its shipbuilding assets and operating fleet.
• The two PSVs became part of MMA’s offshore support fleet, serving projects in Southeast Asia and Australia.
• Post-acquisition, MMA rebranded and integrated these vessels into its logistics and supply operations for offshore oil & gas fields.

These vessels played a key role in supporting drilling campaigns and offshore construction projects, offering high cargo flexibility and DP capability for safe operations near rigs.

Delivering ProductionReady Designs for MMA Offshore

When MMA Offshore commissioned two Platform Supply Vessels (PSVs) at their Batam yard, CMarine was selected to deliver the complete construction drawings and production documentation.

Over a period of 10 months, our team produced:

• A full steel structural model
• Plate nesting drawings for optimized material usage
• NC codes for automated cutting
• Piping, cabling, and HVAC routing
• Equipment foundation designs
• Complete BOMs for all systems

The result was a productionready package that enabled the yard to fabricate the vessels efficiently, with minimal rework and maximum accuracy

The BO 623 Seismic Research Vessel project is quite interesting because it involved multiple design and engineering firms:

Project Overview

• Purpose: A specialized seismic research vessel designed for offshore geophysical surveys, primarily for oil and gas exploration.
• Owner/Operator: Typically chartered for seismic data acquisition in deepwater and shallow-water environments.

Design Responsibilities

• Basic Design:
  • Carried out by Khiam Chuan Marine, a Singapore-based naval architecture firm known for conceptual and preliminary designs of offshore vessels.
  • This stage included hull form development, general arrangement, and compliance with class and regulatory requirements.
• Detailed Design:
  • Executed by C-Marine (Conceptia Marine), focusing on structural detailing, outfitting, piping, electrical layouts, and integration of specialized seismic equipment.
  • Detailed design ensured constructability at ST Marine’s yard and incorporated owner’s operational specifications.

Construction at ST Marine

• Builder: Singapore Technologies Marine (ST Marine), a major shipyard with capabilities for complex offshore and defense vessels.
• Scope:
  • Hull fabrication and outfitting for seismic gear (streamer winches, cable handling systems, survey labs).
  • Installation of advanced navigation and DP systems for precise station-keeping during seismic operations.
  • Accommodation designed for extended offshore campaigns (crew + survey team).

Key Features

• Length: 68 m.
• Deck Arrangement: Large aft working deck for streamer deployment and retrieval.
• Specialized Equipment:
  • Seismic streamer winches and cable reels.
  • Onboard data acquisition and processing labs.
• Propulsion: Diesel-electric or hybrid systems for low vibration and noise-critical for seismic survey accuracy.
• Dynamic Positioning: DP2 capability for precise manoeuvring during survey lines.

Significance

• The collaboration between Khiam Chuan Marine (basic design), C-Marine (detailed engineering), and ST Marine (construction) reflects a typical multi-party approach for specialized offshore vessels.
• BO 623 contributed to expanding regional capability in building high-tech research vessels for global oil & gas exploration markets.

Precision Design for Scientific Exploration

Seismic research vessels are specialized platforms equipped with advanced geophysical equipment for seabed mapping and exploration. For ST Marine in Singapore, CMarine delivered the detailed design for the BO623 Seismic Research Vessel.

The scope included:

• Full 3D structural modeling
• Piping, cabling, and HVAC routing
• Extraction of all BOMs
• Production drawings for hull and outfitting

These vessels require careful integration of scientific equipment, noisereduction features, and missionspecific layouts. CMarine’s design ensured that the vessel met both operational and scientific performance requirements.

Project Overview

• Type: General Cargo Vessel with cellular container capability (essentially a multipurpose ship designed to carry breakbulk cargo and containers in dedicated holds).
• Length Overall (LOA): ~123 meters.
• Builder: PT Bandar Abadi shipyard in Indonesia.
• Timeline: Around the COVID-19 period (2020-2021), which posed challenges in logistics, manpower, and supply chain.

Design Responsibilities

• Detailed Design:
  • Executed by C-Marine (Conceptia Marine), focusing on:
    • Piping, electrical, and machinery layouts.
    • Tank fittings
    • HVAC and Mechanical ventilation
  • Basic Design: Typically provided by the owner or a concept design firm, but C-Marine handled the full detailed engineering package for production.

⚙ Key Features

• Cargo Flexibility:
  • Holds designed with cell guides for containers (usually 20’ and 40’ ISO containers).
  • Capability to carry general cargo when container guides are not in use.
• Deck Arrangement:
  • Large open deck for additional container stowage.
  • Heavy-duty hatch covers for weather protection.
• Propulsion:
  • Conventional single-screw propulsion with medium-speed diesel engine.
  • Bow thruster for improved manoeuvrability.
• Capacity:
  • Container slots: Typically 500-700 TEU for vessels of this size.
  • Deadweight: ~8,000 DWT.
• Speed: ~12-14 knots service speed.

Challenges During COVID

• Remote collaboration for design reviews and approvals.
• Digital workflows for class submissions and owner meetings.
• Delays in steel supply and equipment delivery mitigated through phased construction planning.

Significance

• This project demonstrated resilience in shipbuilding during pandemic disruptions.
• Showcased C-Marine’s capability in detailed engineering for multipurpose/container vessels, integrating structural and cargo handling systems efficiently.

Delivering a 123Metre Workhorse for PTBA, Batam

General cargo ships may appear straightforward, but their structural and operational requirements demand precision and efficiency. For PTBA in Batam, Indonesia, CMarine executed the detailed design of a 123metre cargo vessel.

Our work included:

• Complete hull and structural modeling
• Piping and cabling layouts
• HVAC routing
• Accurate BOM extraction
• Productionready drawings

The design supported efficient cargo handling, structural robustness, and compliance with classification standards.

Know More

Project Scope & Scale

• DDW contracted C-Marine for preparing the engineering drawings for the conversion of Diyina from MODU to MOPU.
• Type of Work: A full Rig Integrity Assurance Program (RIAP) and EPCC concept rig conversion, transforming Diyina from a Mobile Offshore Drilling Unit (MODU) into a Mobile Offshore Production Unit (MOPU).
• Materials & Systems:
  • ~2,000 tonnes of new structural steel
  • ~17 km of piping installation
  • ~180 km of cable and electrical wiring
  • ~90,000 m² of painting and protective coatings

Engineering, Procurement, Construction & Commissioning (EPCC)

• Drydocks World acted as the lead EPCC contractor, marking its first delivery under the EPCC model for concept rig conversions.
• The project reflects Drydocks World’s strategic focus on drifted offshore conversions and refurbishment projects.

Client Collaboration

• Executed for National Drilling Company (NDC), the Diyina conversion is noted as the first of 17 projects completed by Drydocks World for NDC.

Role of C-Marine

• Prepare the 3D Model of the Rig complete with Structure, Piping, Electrical, HVAC and Hull Outfitting.
• Remove the existing pipes and fittings as well as equipment and ducting and cabling and replace as per the design.

Summary of Key Takeaways

• Leveraged Drydocks World’s RPCC delivery model, a first of its kind concept rig conversion, integrating integrity, refurbishment, and commissioning services.
• Delivered scope included major structural, piping, electrical, and coating works with strong safety performance.
• Solidified Drydocks World’s partnership track record with NDC and capability in rig conversions under challenging offshore standards.

From MOPU to MODU for NDC Abu Dhabi

CMarine played a pivotal role in converting the Rig Diyina from a Mobile Offshore Production Unit (MOPU) to a Mobile Offshore Drilling Unit (MODU) for the National Drilling Company, Abu Dhabi.

Completed in just six months, the project involved:

• Detailed structural design
• Piping and cabling integration
• BOM extraction
• Production documentation

Rig conversions require deep understanding of offshore safety, load paths, and operational requirements. CMarine’s engineering ensured that the converted rig met all functional and regulatory expectations.

Project Overview

• Client: PPL Shipyard (Singapore), a major builder of offshore rigs.
• Rig Type: Freedom Class Jack-Up Rig, designed by Baker Hughes.
• Scope for C-Marine:
  • Prepare Class-approved drawings based on Baker Hughes’ input design.
  • Develop a fully accurate 3D model of the rig structure and systems.
  • Extract and annotate drawings to meet classification society standards (ABS, DNV, or similar).

Engineering Workflow

1. Input Data Review
   • Received conceptual and preliminary drawings from Baker Hughes.
   • Verified compliance with class rules and PPL Shipyard specifications.
2. 3D Modeling
   • Built a detailed parametric 3D model of the jack-up rig using advanced CAD tool Tribon M3.
   • Included hull, legs, cantilever, drilling package, piping, and structural reinforcements.
3. Drawing Extraction & Annotation
   • Generated fabrication drawings for hull blocks, leg chords, braces, and machinery foundations.
   • Annotated drawings per class requirements (weld details, material specs, tolerances).
   • Produced system diagrams for piping, electrical, and safety systems.
4. Class Approval Process
   • Submitted drawings to classification society for review and approval.
   • Incorporated feedback and revisions to achieve compliance.

Key Deliverables

• Hull Structural Drawings: Including scantlings and load calculations.
• Leg & Jacking System Details: Critical for jack-up stability and operational safety.
• Piping & Electrical Layouts: Supporting drilling and accommodation systems.
• General Arrangement (GA): Showing deck layout, cantilever reach, and equipment positioning.

Significance

• This project demonstrated C-Marine’s capability to:
  • Convert conceptual designs into production-ready documentation.
  • Use 3D modeling for accuracy and clash detection-an advanced approach for 2006.
  • Interface with class societies for compliance, ensuring smooth fabrication at PPL Shipyard.

Beyond specialized vessels, C-Marine has delivered detailed design packages for a wide range of platforms including Offshore Patrol Vessels (OPVs), dredgers, and other workboats.

Each project involved:

• 3D structural modeling
• System routing (piping, cabling, HVAC)
• BOM extraction
• Production drawings

Even when the scope appears similar, each vessel type brings unique operational challenges. CMarine’s strength lies in adapting our engineering approach to the mission profile, ensuring accuracy, efficiency, and production readiness every time.

Versatility Across Marine Sectors

Beyond specialized vessels, CMarine has delivered detailed design packages for a wide range of platforms including Offshore Patrol Vessels (OPVs), dredgers, and other workboats.

Each project involved:

• 3D structural modeling
• System routing (piping, cabling, HVAC)
• BOM extraction
• Production drawings

Even when the scope appears similar, each vessel type brings unique operational challenges. CMarine’s strength lies in adapting our engineering approach to the mission profile, ensuring accuracy, efficiency, and production readiness every time.