Metocean conditions have been identified as the main factor affecting the progress of a marine
project [7–10]. Identifying the available weather windows is a key part of the optimisation process
[11,12], and allows the detection and understanding of sensitive tasks and/or vessels, choke points
and critical paths to occur. Mojo Maritime Ltd., in collaboration with the University of Exeter, has
developed a software package specifically engineered for the analysis and optimisation of marine
energy installation – Mermaid (Marine Economic Risk Management Aid). Mermaid performs a holistic
analysis of the installation procedure using a variety of input data (such as metocean data, project
information and vessel characteristics) to provide a good estimate of the project length and cost.
Mermaid can also be applied to optimise an installation process, allowing informed decisions to be
made regarding such issues as vessel types, operating ports, task ordering etc.
This paper uses the Mermaid software to analyse a case study to determine the cost implication of
installing a series of Tidal In Stream Energy Converters (TISEC) using different vessel types. In this case
study two vessels are considered: a traditional Offshore Construction Vessel (OCV) with Dynamic
Positioning (DP) capabilities and a custom vessel specifically designed for operating in the harsh
conditions often encountered at such deployment sites – the HiFlo-4 (HF4) installation vessel
developed by Mojo Maritime Ltd.
Mermaid methodology