The fleet has separated into two groups, east and west. The east pack, led by Dongfeng Race Team, has been in slightly more pressure, while Team Alvimedica, 45nm west, has been in lighter breeze. On Saturday, Team Alvimedica was out of the lead by only 3.2 nm. During the night, the black and orange boat had been losing positions on every report, and currently stands in fourth place behind Team Brunel in second and MAPFRE in third.
Abu Dhabi Ocean Racing, now in fifth place, 18.2 nm from the leader, had opted for the western option, and is now separated from the leading pack 25nm to the west. Team SCA, currently in 6th place, have had a hard day, feeling like they were down on speed compared to the fleet. They were forced to perform a back down maneuver to clear the foils from any debris they may have collected.
Ahead of the fleet, the Chinese-French team, Dongfeng Race Team, had been making just 1 mile of gain overnight into Sunday. Caudrelier’s crew has proven before to perform very well on these conditions and it wouldn’t be a surprise if they continue making gradual gains.
During the course of the Volvo Ocean race, the thermally driven ocean currents that circle the world’s oceans play a huge part in global weather systems and affect the fleet.
As the warm waters of the equatorial flow move west they hit the Brazilian coastline exactly where the fleet are currently sailing. As it nears the coast it splits north, eventually becoming the Gulf Stream, and south, the south equatorial current.
Approximately 25nm off the coast there is an underwater cliff where the depth changes from 3000+ meters to less than 50m.
As the current gets near this cliff edge, it will follow along it. This is where we might see some gains for Team Alvimedica and Abu Dhabi Ocean Racing as they may get to the faster water before the other boats.
The angle of flow with them will be pushing them from behind, however, for the rest of the fleet, it will be more side on.
This could affect the apparent wind speed of the boats, effectively meaning Alvimedica and Abu Dhabi will have around 1 knot pushing them forwards with the wind, and the others have 1 knot of wind pushing them sideways away from the wind.
All the boats wait in anticipation of the south-easterly trade winds, which at the moment look like they will power the fleet through the notoriously dull doldrums.
Source : http://www.sailingscuttlebutt.com/2015/04/26/volvo-ocean-race-good-days-bad-days/