Now 1500km from Cape Town and 1100 km from the closest point of South Africa’s EEZ, Challenger continues to push onwards toward her goal of crossing the South Atlantic from East to West.
Over the past few days Challenger has been pushed further to the north than we wanted, but was still left in a position where we can follow the path outlined last time by the purple line in the image above. In the coming weeks, we will aim to surf the southern side of the two eddies as we work East-Northeast across the stream coming around the edge of South Africa.
In order to make the entry point for the leading eddy, we will change the way point to 35˚S, 5˚E
Power use is remarkably steady at 2.3 Amp Hours/day. The recent peak at 2.8 AH/day was when we turned on the altimeter to get across the final group of seamounts.
If our battery power calculations are correct, at this use rate, we have 150 days of battery power left on board. 1500 km to go with 150 days of power on board means we need to beat 10 km/day made good to make it. So far throughout the mission we have only come near that minimum once at 11km while presently we are closer to 30 km/day
And this speed is something we need to try and keep steady for as long as possible:
Currently, our average heading error (red) is small – only a degree or so, however the standard deviation of the heading error (blue) is trending upwards. This heading error is a sign of biofouling and most likely the barnacles which have plagued the long duration glider missions over the years.
As the critters grow, the vertical speeds slow down, less water flow over the fin, resulting in more heading errors.
Hopefully we’ll be able to maintain Challenger’s speed as we work our way from eddy to eddy and get to South Africa as soon as we can
Force Wind Sea & Honor