Floating systems &
moorings

The deep experience of Apollo naval architects and engineers spans most configurations of floating structures, from semisubs and spars, to novel marine energy structures. Through industry-favoured software applications we prepare calculations that are essential to the design process, including diffraction analysis, frequency domain response calculations and time domain simulations. Response amplitude operators (RAOs) and quadratic transfer functions (QTFs) can be generated for use in response calculations and operability assessments. Our engineers have the insight to calibrate software with model tests and real world data.

Whether for the periodic update of the stability book or for proving a novel system or operation, robust and assured hydrostatic calculations are essential. Apollo teams are experienced in the generation of ballast plans and stability calculations, regularly attaining independent validation by class societies. Where deadweight surveys and inclining experiments are needed then Apollo’s naval architects are ready to support.

While the floating renewables is relatively new, moorings have been around for a long time and there is a vast body of knowledge on how to hold dynamic, floating systems within operational limits, and how to survive extreme weather. Apollo engineers have decades of experience in mooring design, analysis and integrity management in support of a cross section of the whole energy industry. Static and dynamic mooring design analyses are available in frequency and time domains using OrcaFlex™ and Aqwa software applications. From fully coupled, nonlinear analyses to fatigue calculations, conceptual designs, operational procedures or even just a spot check, your project requirements will be understood and fully satisfied.

Loads at the structural interface are often the most challenging, with the greatest dynamic and static loading working within the slash zone of a floating structure. Effective design requires a full understanding of the load regime, equipment capabilities and structural foundation. Apollo’s mechanical and structural engineers work closely with naval architects to provide assurance on design solutions and to effectively integrate 3rd party equipment with the hull structure for long term applications.

The floating offshore wind and marine energy sectors have a broad range of structural design concepts preparing for or in operations. Each has their own dynamic characteristics and load regimes, but the fundamental engineering principles are the same. Apollo naval architects and structural engineers work together to evaluate the potential performance and optimisation of floating foundation concepts, working from concepts through to thorough front end engineering design deliverables. The service does not stop there and detailed design services are available for subsystems and secondary structures.

Achieving sufficient fatigue integrity is often the greatest challenge in a long term mooring, and requires a combination of analytical expertise with practical interpretation of basis information. Apollo is experienced in the development of detailed fatigue analyses for mooring systems, from calibrating the basis of analysis against model tests, through to loadcase generation, S-N curve selection and overall interpretation of life expectancy.

The overall risk profile of a floating system is a complex, with multiple interacting systems, dynamic environmental effects and operational procedures. Apollo are often called in to support the technical risk evaluation of a system or process using HAZID, HIRA, QRA, FMEA/ FMECA methods. Sometimes the issue is to building a common understanding of risk and mitigations, and Apollo engineers are experienced in facilitating the panel review of an issue or working method.