As the Northern Hemisphere transitions into spring, the current weather pattern and icing situation in the North Atlantic provides some interesting routing considerations.
Winter seasons vary considerably in severity depending upon the relative frequency and paths of migratory storm systems and the degree of cold Arctic air presence off Newfoundland/the Canadian seaboard. These factors determine the volume and extent of the sea ice in the region.
Currently, the southern extent of the Atlantic iceberg field off Newfoundland is much further north and reduced in extent than is typical for this time of year. Image 1 shows the North American Ice Service iceberg (NAIS) Analysis for 8 April.
The climatological median ice berg limit for Mid-April extends to 42N with the extreme Iceberg limit being (approximately) 40N, so there is currently some 550nm more safe open water available for routing options than in severe years.
The opportunity to exploit this open water for shorter Great Circle (GC) routing also depends on what the weather pattern is doing. There is currently a persistent high pressure ridge across Greenland which will ‘block’ gales from progressing along their typical east-northeast track in the North Atlantic. Instead, gales will tend to drift slowly south of Newfoundland for several days, before heading east-southeast towards the Azores and slowly weaken (see Image 2). This blocking high scenario can be difficult to move and, as a result, broad ridging will extend from Greenland across the NE Atlantic to France over the next week or so.
The combination of these two features allows the opportunity for more optimised GC routing options rather than typical longer Rhumb Line (RL) routes further south used at this time of the year.
Below is an example of a ship transiting from New York to Teeside, UK with three options:
1) Our recommended Green route, the most direct route uses the ECA zone off the US Seaboard and GC across the Atlantic via Pentland Firth;
2) The Master’s initial choice – Pink RL route that minimises time/distance in the ECA off the US and uses the English Channel, and
3) An alternative Brown route if the vessel wishes to minimise time/distance spent in the US and European ECA zones and uses a combination of RL and GC routing via Pentland Firth.
The weather and current factors (WF/CF (in KTs)) are pretty similar. A small positive CF for Brown from the Gulfstream does not make up the difference from the shorter Green route:
1) -0.25/-0.11,
2) -0.17/-0.12,
3) -0.25/0.04.
The result is that Green will save 40.9hrs steaming compared with Pink, while Brown saves 24.4 hrs. Image 3 displays the three routes with ECA totals included together with representative hire/bunker rates.
The Total Voyage Costs are based on VLSFO bunker prices $481/MT and LSMGO bunker prices $537/MT. The numbers assume an estimated hire cost of $12,000/day and the vessel consumes 15MT/day based on a SOG of 11.5 kts. Our recommended green route saves $32,170 compared with the Master’s initial route, while the minimised ECA Brown Route saves $22,226. ECA zone transits can translate in to real savings. In this example, the Green Route effectively kept the vessel on the safest, shortest, and most cost effective route.
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