Underway - Pacific Crossing Notes: A Sailor's Guide to the Coconut Milk Run - page 114

A Word About Currents
Along some stretches of the Coconut Milk Run, currents can have a significant impact on
your passage times. The East Australian Current is one prominent example. Currents can
also make a big difference on a passage between Panama and the Galapagos Islands. Re-
ports from fellow boaters leaving the Galapagos Islands for the Marquesas indicated that
the generally west-setting current south of Isabella Island seemed to reverse every seven to
ten days for about forty-eight hours. We learned that lesson too late and spent one twenty-
four hour period tacking 100 NM only to end up a mere 10 NM from the previous day's po-
sition.
Pilot Charts [#13] that show the average historic wind conditions on the world's oceans also
provide a good representation of steady, large scale current phenomena like the Equatorial
Current. However, they lack the resolution (both in space and time) for smaller and more
dynamic features.
One of the few sources of current prediction data that is accessible underway is Meteo
France's global prediction model of ocean currents. Its output can be obtained as GRIB
files via an email interface. Some popular GRIB file viewer software has trouble displaying
the data but OpenCPN's GRIB plug-in [#14] works well (see below ) .
To get Meteo France current forecasts, send an email to [e-mail] , with
the subject Requete (request) and the following text in the message body:
@mto@reqt@grib@
A 1
Z 154.750 -30.250 6.500 7.500
M 0.5
D 10
P courant
G 24 48 72 96 120 144 168 192 216 240
C bzip2
s 2.1.3
@mto@reqt@fin@