The walk-to-work module of ODST gives decision support towards a gangway operation.
The module gives the operability of a gangway operation between a service operation vessel (SOV) and another floating object. The module offers flexibility towards using different connection locations and draughts of the floating object as well as a range of different headings.
The walk to work module is split into three separate pages.
The HOME page shows the operability for all simulated scenarios. Along with high-level forecast data.
The Weather page offers a deep dive into the forecast data that the operability is based upon.
The Response page allows an interested user to compare to look at the different limiting responses and compare them with their allowable limit.
HOME page
The HOME page is a clear overview of the operability for the coming 5 days, along with the significant wave height and wind speed.
To offer a closer view of an imminent gangway connection the user has the possibility to zoom in on the next 24 hours of the forecast.
The vessel is configured with a heading strategy that is used as the default for forecast-based operability predictions. When planning an upcoming connection, the user can override the default heading by inputting the actual vessel heading to reflect the expected conditions at the time of the operation. As the vessel heading for the coming days is generally uncertain, the heading override function is disabled in the 5-day forecast view.
The configured heading strategy is displayed in the user interface for reference.
Note that the heading override is limited to the pre-simulated heading range, as simulating all possible headings would be computationally prohibitive. Specifying a heading outside this range will cause parts of the operability bar to display "No data".
Weather page
The weather page of the walk-to-work module is the same as for other ODST dashboards. The user manual for the weather page can be found here: Explore Weather | 4insight.
Response page
The response page shows the results from the simulations for all the responses limiting the gangway operation. This offers an in-depth view of why the operability assessment shows the results it does. For each simulated response, two time series — one representing positive and one representing negative values — are shown alongside their respective limits. The user can browse between different limiting responses. In the bottom right corner of the page, a side view of the gangway is shown along with the allowable limits for gangway stroke (outwards and inwards) and luffing (angle relative to the sea surface).
A large number of simulations is carried out every time a new forecast becomes available, and a delay should be expected from when a forecast is issued until all results are available in ODST. When simulations are ongoing, a line is shown on both the Home and Response pages separating the results from the new forecast (to the left of the line) from those of the previous forecast (to the right).
The same functionality for toggling of the different scenarios and heading override as for the HOME page is available on the Response page as well.
Heading sensitivity
A heading sensitivity of +- 15 degrees have been implemented in the walk-to-work module. This means that for every response the worst of response of three simulations representing the nominal heading and the nominal heading +- 15 degrees is chosen.
When the heading is overridden the simulated headings might not match the chosen heading and the sensitivities. In this case the simulated headings closest to the requested nominal heading and nominal heading +- 15 degrees is chosen.