Vessel Motion Measurement and Forecast for Safety

The response of a vessel to wave conditions can be determined using the vessel’s displacement Response Amplitude Operators (RAO). Measuring and forecasting heave, pitch and roll can greatly improve the safety of operations.

Using the vessel’s RAOs provided by the vessel operator, RPS is presently providing clients with:

Statistics and Operability

Using measured wave spectral data or hindcast modelled wave spectra, RPS are able to provide an analysis of a vessel’s suitability for working at your location. This includes downtime analysis and operational window estimates.


Forecasts are provided to cover short term 12 to 24 hour operations and the trend up to 8 days to allow for operational planning. Typically forecasts are updated every 12 hours. The forecast wave spectra driven RAO calculations are superior to planning based on a Significant Wave Height (Hs) alone (as shown below), providing increased operational time and with higher accuracy.

Timehist if MRU and DWR Calibrated Forecast

MRU and DWR Calibrated Forecast

RPS can provide a vessel mounted Motion Reference Unit (MRU) with real-time communications or connect an existing MRU to our systems. Using MRU data to calibrate forecasts provides a higher accuracy. A wave buoy transmitting via satellite can be deployed, in addition to or instead of an MRU. Measured waves calibrate the model from which vessel motions are derived. Having both Waves and MRU offers redundancy and allows RAO calculations to be checked.

Data Display

Measured and Forecast data can be displayed on our dedicated web display pages or provided via a web service such as WMS or WFS for integrating with your in-house GIS displays.

Verification Reports

Monthly verification reports review the previous month of forecast and measured MRU or DWR data. Verification reports are valuable to confirm the operability of the vessel for management review.

End of Project Review

At the completion of the project this review will assess how closely the Statistics and Operability report matched the actual measurements and forecasts during operations.