The 3 steps in calculating the tidal window: time location diagram, cross current exclusion and finding the route.
In order to get a tidal window advice PROTIDE uses a progressive scheme in which it makes extensive use of calculating the bottom touch probability:
- PROTIDE first searches for the locations and times where the probability of a bottom touch is just equal to the safety criterion. These determine the borders of time intervals when it is safe to be at a certain location. This can be shown in a time location diagram.
- Next, the moments in time that the cross current is too strong at the entrance of the harbor are excluded.
- The last step is determining a navigational route which, given a certain speed, only passes through safe time intervals and passes the harbor entrance without too much cross current.