A screenshot from TZ Navigator V3 showing some of our past trips (in red) and a couple of sketched in options (in blue). The forecast is long range one paused on 12 August and the little blue boat icon shows our forecast position as if we were following the lower blue track. The coloured blobs show rain and I often include that layer as it shows up the fronts well.
After a quick refit of Pelagic Expeditions’ “Pelagic Australis” we are about to depart on the delivery voyage to Stanley. There will be just four of us aboard Alec and Giselle Hazell and Paula and I. We have all been working together on the refit and all of us have done this trip before.
Typically the route will take us West North West out of Cape Town and then when we feel the time is right we’ll cross through the high pressure zone that is normally present (known as the Saint Helena high). That should give us winds from abaft the beam for most of the trip across and then somewhere east of the Rio Plata we choose our routing to Stanley. Cutting the corner and ending up north east of Stanley is rarely a good idea but sometimes we can get away with it shaving a couple of days off the trip.
This year we are making the voyage a month earlier than normal so can expect a less well formed high and for the Rio Plata to be spawning low pressure systems that will be rolling across our path. Further south we’ll have the lows developing off the coast of Patagonia to negotiate.
The general routing has been known for centuries now and the traditional pilot charts tell us where the systems are typically located. Modern weather forecasting allows us to fine tune our routing too some extent particularly when we choose where to dive south toward the Falklands and for our approach to Stanley. The route across from Cape Town is just a matter of how far north we have to go to avoid having to beat into strong westerlies.
No weather forecast is accurate enough to plan a whole voyage that will last longer than three weeks so we take a general approach and then use the weather tools that we have aboard and experience to fine tune things. Usually you can trust the forecasts for about three days, the forecast out to five days may or may not happen and beyond the probability of it actually happening diminishes dramatically.
As we are not racing but delivering a boat that has a 25,000 mile season in high latitudes ahead of it we don’t want to break anything, and because we want a comfortable ride, we take a conservative approach to our routing generally erring on the side of an easy ride for the boat and for ourselves.