A Complex Passage    

Consider a passage from the St. Lawrence river to a West European port where the geographical routing options are numerous. In the illustration below there are up to four major options for the Atlantic crossing.  Not all of these passages are available throughout the year which will require the use of user defined restricted areas and adjustments to route options.

Quite often the best place to start is by using the routing engine to predict the Least Time Track. Consider a passage from Escoumains Pilot station (48 19 N 69 25 W) in the St. Lawrence River to Ijmuiden at 13 knots.

The Least Distance Track is predicted to be via Belle Isle and North about the UK. However storms in the North Atlantic have forced the LTT prediction further south.  This is a situation that could change if the ETD of the vessel is altered which is why it is advisable to run frequent initial route recommendations prior to departure.

For the purposes of this exercise consider that the Master has declined to proceed on passage via the strait of Belle Isle. Also consider that the International Ice Patrol is reporting the limit of known ice bergs as far south as 45 N east to 40 W.  You should now disable the  Route Option for Belle Isle and edit or create a restricted area for Ice bergs. (See previous lessons).

 The Least Distance Track has now merged with the Least Time Track and both are substantially further to the south. If the decision not to pass through Belle Isle is normal for the time of year and ice is a concern then the initial route recommendation has been "optimized" for the prevailing circumstances.

If complex passages are not for you then RealDistance.com would be pleased to route your vessel.