13 Feb 2015

Developing a moored vessel response model

DHI is developing a state-of-the-art model to help clients perform high-precision moored vessel response assessments based on dynamic wind, wave and current conditions.

Understanding how moored vessels respond to wind, wave and current conditions is essential to port and terminal authorities, their contractors, as well as port designers and operators. The calculation of highly unpredictable moored vessel motions is needed, for example, for the design of mooring lines, and to determine if vessels can be safely moored at ports and terminals, usually for the purposes of loading and unloading.

Compared to existing products in the market, the frequency response solver of our model allows for very fast run times, and we are also able to offer a fully hydrodynamic analysis because of the way wave conditions are entered. 

The final model – which has an extremely user-friendly graphical user interface – is composed of three well-integrated elements:

  • Dynamic Vessel Response Simulator (DVRS)  
  • Frequency Vessel Response Engine (FVRE)
  • Dynamic Vessel Response Engine (DVRE)

The DVRS allows users to input data and configurations in order to set up various scenarios. After entering the required data, which includes the geometric and hydrodynamic characteristics, the wave frequency response of the vessel is then calculated by running the FVRE. The DVRE is launched as a final step to calculate the moored vessel response in the time-domain. The generated data from the engine is mapped to a time series distributed file system (DFS) document which can be accessed with the MIKE platform on a Microsoft Windows server. This makes it easy for users to visualise and post process the dynamic vessel data.

DHI has been providing the assessments of moored vessel response for years. However, these assessments have always been reliant on third party programs. Thanks to our dedicated research, development and innovation (RDI) efforts, we have now developed a fully independent DHI tool for use together with our existing technologies.

Large LNG tanker moored to a GBS in a bi-modal seastate.