Cape Town to Stanley – a Wintery Voyage

TIMEZERO ambassador Chris Harris has been working at Skip Novak’s company Pelagic Expeditions which runs two yachts: Pelagic Australis and the original Pelagic. “I have worked on both boats since 2007 in all capacities, but these days I work mainly on technical support during the refits, via an occasional email during the season and make some delivery/re-positioning voyages.” Recently he made the trip from Cape Town, South Africa to Stanley, Falkland Islands. Here is his resume of the trip:

Early August – After a six week refit it was time to deliver “Pelagic Australis” to her summer cruising grounds in the South West Atlantic and Antarctica. Four of us, two couples, Alec and Giselle, myself and my partner Paula had been working on the boat in Cape Town, South Africa, since mid-June; repairing, overhauling and preparing everything for the coming Antarctic season. “Pelagic Australis” is a 24m aluminium sloop custom built for high latitude expedition support work. A typical season for the boat runs over nine and half months and 25 to 30,000 miles with typically a 10-week refit in Cape Town, South Africa.

The refit repairs the season’s wear and tear and prepares the boat for the coming season.We planned to depart Cape Town after an abbreviated six-week refit so that Pelagic Australis would be back to Stanley, in the Falkland Islands, ready to depart on a winter climbing expedition to South Georgia in early September. This voyage is one that all four crew have made before. The conditions to be expected are well known to us. The typical voyage plan follows the route in the following screenshot from TZ Navigator v3.

Departing Cape Town we head WNW towards a waypoint at 30S 15W and then WSW towards a point off the River Plate estuary and then south to Stanley. The weather systems that most strongly influence this choice of route are the position of the South Atlantic high and the low pressure systems forming over Patagonia and spinning up as they head out into the South Atlantic. Our aim is always to make some northing out of Cape Town to get north of the Westerlies on the south side of the South Atlantic high.

To save time we usually try to find a short route through the high and motor across, rather than sailing all the way around the high which would take us long way north and well off our route. This being the re-positioning voyage of a working sailing vessel some of our decision making differs from that taken in cruising and racing scenarios. Once at the mid-Atlantic waypoint the weather is usually variable and we can sail the making towards the River Plate waypoint.

As we get within 500 miles or so of the waypoint we are watching very carefully for an opportunity to cut the corner. Being NE of Stanley is rarely a smart place to be with the SW’ly winds predominating in this season. The usual tactic is to sail fairly close to the River Plate waypoint before turning south but there is often an opportunity to cut across a couple of hundred miles off the corner but no more than that.

Once we turn south we have about 1000 miles to run to Stanley; which for this boat in the expected conditions should take about five days. This means that with a low pressure system spinning off the continent about every three days we will get the nasty end of at least one of them.

So that was the plan; now what actually happened?

As you can see from the screenshot above the high was not at all dominant at the time of departure however it did, weakly, assert itself after the low blew itself out. We motor sailed against fairly light headwinds towards the mid-Atlantic waypoint. This year we were on the route a month earlier than usual and the South Atlantic low pressure systems were still tracking along their winter routing. This pushed us further north than usual by a couple of degrees. The temperature was noticeably cooler than usual.

Once west of the waypoint we were forced to sail further along a westerly heading rather than work slightly south as usual. We download weather data at least once a day, usually in the evening when we can discuss the forecast over dinner and make a plan accordingly, when things get interesting or complex we take a morning forecast too. In the following TZ Navigator v3 screenshot (it’s taken with the software set to night mode which is useful for preserving night vision) you can see various routing options on the screen; the yellow route is my latest prediction.

If you compare the prediction with the track, below, you can see that the shape of the course eventually sailed is fairly close. To save satellite bandwidth I usually select only wind, pressure and rain when ordering a GRIB file, at 12 hour intervals. Occasionally when analyzing a tricky situation I get the 500mB height and temperature or decrease the time interval to 6 hours. The reason for downloading the wind forecast is obvious; the rain graphics give me a better idea of where the fronts lie and the pressure isobars give shape to the weather systems. The 500mB height can give clues to the probable route of a system.

I routinely compare forecast true wind direction and atmospheric pressure with the actual data from the wind instruments and barometer. This gives me an idea of how accurate the forecast is in terms of position and time. TZ Navigator v3 has the ability to tweak the GRIB file parameters for wind, waves and position (TIMEZERO menu -> Options -> Routing) which is very useful if observations show that the GRIB is off in any way (very common in mid-ocean areas short on weather buoys and ship observations).

On this voyage I did not download wave data or use TZ Navigator v3’s routing capabilities simply because of the way we sail and motor this yacht. On my own yacht on pure sailing trips those features are very useful. Instead the routing was done by Alec and I based on our knowledge of the boat, consideration to our comfort and the aim of delivering the boat to Stanley in perfect condition for the hard season ahead.

You can see from the following screenshot that we were able to cut the corner somewhat by working south west through a couple of systems rolling out of the River Plate estuary simply by always sailing the tack that gave us the best VMG towards Stanley. We would probably not have risked cutting the corner like this without the benefit of modern forecasts and the ability of software such as TIMEZERO to play out the various options open to us.

The final run into Stanley was, in this case, a straight forward race to beat the center of a deep low bringing a forecasted 40 knots with it. We had back to back daily runs of 200 miles and docked at Stanley in a breeze of about 30 knots; later we had 50 knots and were more than happy to be alongside.

The voyage was very average for this route, we took an average 26 days, the highest wind that we saw was a gust of 40 knots. Good routing and planning meant that we only had to put in one reef in less than ideal conditions (it was of course very dark, very wet and very cold!) we caught a higher than average number of fish and burnt a little more fuel than usual due to the unavoidable light headwinds during the first half of the trip.

We only had two technical issues; a fault with the autopilot that we traced to a worn out rudder position indicator which we changed out for a spare and a faulty wind instrument cable that was also changed.

Time for some down time!

Update Your Charts

We have two recently updated C-Maps charts that cover South America and include part of Chris Harris’ (updated in May of 2016) so if you’re planning a trip to or around South America make sure your charts are up to date so there won’t be any nasty surprises.

COSTA RICA TO CHILE TO FALKLANDS WVJSAM500MAP10.2