Page 1 of 5 Marine Construction Support & Dimensional Control Key Specifications Surface and Subsurface Positioning IRM Support Lay Support Trench Suport Installation Support Metrology As-Built Heavy Lift DOF Subsea provides subsea positioning and marine construction services to support client field installation projects from near shore shallow fields to ultra-deep offshore developments. The company s extensive experience has been developed on a worldwide basis, utilising both the DOF fleet and client vessels. We pride ourselves on being at the forefront of industry technology and techniques, as well as maintaining strong capabilities with industry wide standards and practices. Proven Track Record By utilising industry proven navigation software, high accuracy heading and attitude solutions as well as subsea acoustic solutions, we ensure a flexible, cost effective, efficient and dependable positioning solution tailored to meet client s requirements. Experience in LBL acoustic and surface rig move operations, barge positioning, anchor handling, heavy lift support operations, platform and SPAR tow out as well as other in-house support services. Positioning packages are enhanced through the use of dimensional control, bathymetric surveys, customistomised software packages and real-time 3D visualization of operations.
Page 2 of 5 Lay Support Typical flowline and umbilical installation spreads involve mobilising surface and subsurface equipment on board vessels. In many cases, existing shipboard equipment such as DGPS units or USBL systems are utilised (where equipment specification requirements are met). This has the benefit of speeding up the mobilisation time as well as reducing costs to clients. DOF Subsea uses WinFrog and Eiva software for navigation and can provide data telemetry solutions on a common platform so that the required information can be easily passed between vessels. Subsea Positioning The company has an extensive track record supplying clients with ROV tracking requirements and interfacing survey sensors to the most widely used ROV systems. This can provide clients with the level of positioning accuracy required, utilising USBL or LBL acoustics. Acoustic Positioning / Metrology DOF Subsea has vast experience in providing subsea positioning expertise in metrology for precise relative subsea measurement. The company utilise the most technically suitable package to suit the requirements of each scope of work and this may include multiple methods to overcome environmental factors and existing infrastructure. The company currently provides the following industry recognised methods: Long Base Line (LBL) Smart Wire Inertial Navigation Systems (INS) Photogrammetry Inferred Metrology The company has developed its own metrology data calculation software package where readings are input seamlessly from Sonardyne, integrating Fusion and Metro for data collection. DOF Metro contains a selection of Quality Control tools and DNV approved output report.
Page 3 of 5 Heavy lift / Renewables support DOF Subsea provides cost effective solutions for the installation of offshore renewable projects on a project by project basis. We work closely with our clients to develop and provide innovative solutions that allow our clients to be confident of the support during installations in a timely manner. Regardless of size or shape, of structure DOF Subsea provides the survey support for the installations to take place in a safe, controlled and timely manner, using in-house software packages to fully assist our clients. Rig Move & Specialist Tow DOF Subsea supplies advanced navigation systems, competent personnel and, with extensive experience, is a leading provider of offshore survey services to the Oil & Gas Renewable and Construction Industries Worldwide. Utilising industry-proven navigation software, high accuracy GNSS, gyrocompasses, GNSS Heading solutions as well as subsea acoustic solutions, DOF Subsea ensures a flexible, cost effective, efficient and dependable positioning solution tailored to meet client requirements. We have experience in acoustic and non-acoustic rig move operations, barge positioning, anchor handling, platform and SPAR tow out as well as other in-house support services. Positioning packages are enhanced through the use of dimensional control, bathymetric surveys, customised software packages and real-time 3D visualization of operations. DOF Subsea is accomplished in providing data telemetry systems for tasks where numerous vessels are involved and the communication of positioning information is critical, and has the ability to remotely view and control the individual tug systems from the master unit. Tow-Out and Structure Installation DOF Subsea has supported numerous tow-out and structure installation operations. Recent operations have been conducted in Europe, Gulf of Mexico and West Africa and have included semi-submersible platforms, SPAR s and TLP s.
Page 4 of 5 The projects consist of a variety of survey services at each stage of the operation from dimensional control of the structures and bathymetric surveys of the route to the real-time visualisation of the upending and ballasting. By building on the experience that has been gained on each tow-out operation and combining it with the existing knowledgebase, DOF Subsea have developed equipment, software and procedures to provide a leading service. Tow-out specific software packages have been developed to provide solutions tailored to client needs, including `SPAR Controller and `Ballast Monitor. 3D & 4D Visualisation C3D Visualisation is a unique software system which creates a geographically and dimensionally accurate 3D subsea environment created exclusively by DOF Subsea for the offshore survey and subsea construction industry. C4D Visualisation integrates all of the features of C3D, adding real-time capability. It enables the operator to view the movement of any surface vessel, ROV or underwater equipment. The C3D System provides operators, contractors and engineers with the tools to visualise a field throughout all phases from conceptual design, procedure generation, installation simulation to real-time operations offshore. C4D being a real-time 3D visualisation tool provides a dimensionally accurate subsea environment developed exclusively by DOF Subsea for the Offshore Survey and Construction industries. It is compatible withengineering software and data stored in major GIS systems such as digital terrain models or bathymetry for routes or arrival locations. Operators can view surface vessels as they move in real-time as well as the position of subsea equipment and structures. Dynamic modelling utilising the industry recognised mathematical calculation engine Orcaflex can provide real-time display of catenary curves from provided survey positional information.
Page 5 of 5 Dimensional Control Underpinning and complementing the services that DOF Subsea provide to the offshore survey and construction industries, is a commitment to be the leading dimensional control survey provider. Land, Geodetic & Engineering Survey techniques have been adapted for the offshore engineering environment, which combined with specialist software and the latest modern high precision instruments, competent and experienced personnel, produces high accuracy 3D spatial information. This information plays a critical role in the installation of assets where accurate 3D relationships must be determined. Our Surveyors can report the position and orientation of survey interfaces hubs and flanges onshore prior to installation. Dimensional Control teams can assists fabricators and provide third party checks during the construction of a subsea and surface assets, ensuring a fit-first-time is achieved. Using these services onshore during fabrication provides continuity during projects where an understanding of the requirements of offshore survey is crucial. We recognise the importance of as-built information to our clients. To ensure that a complete record is obtained laser scanners are used to generate point-cloud information, from which dimensionally correct CAD compatible models are produced. The point-cloud can be issued, modelled or stored digitally for future reference. Having access to this data means that even though structures may lie at depth, dimensional control information is at our finger tips.