Safety - Pacific Crossing Notes: A Sailor's Guide to the Coconut Milk Run - page 64

the same large area covered by the synoptic charts. This gives us an idea of what the com-
puter model thinks will happen beyond the forecast horizon of the synoptic charts (typic-
ally seventy-two hours). We take the GFS data with a grain of salt, given that it is “raw
output” from a computer model. Still, it helps us to spot potential issues early on.
Our third source of information is satellite images which we can also receive via radio
fax. We find these very useful for getting an idea of the intensity of fronts and conver-
gence zones. The synoptic charts are a “daily must” for us. GFS data and the satellite im-
ages, on the other hand, we may only receive every few days or when weather develop-
ments require more stringent tracking.
Q: Do you use a weather routing service?
Markus: We subscribed to Chris Parker's services in the Caribbean and found his service
especially helpful when weather windows were very narrow and late or early season trop-
ical storms posed a significant threat. In the tropical Pacific outside cyclone season, on the
other hand, we don't see the need for a weather router. The passage from Tonga to New
Zealand was a bit more challenging again with respect to finding a suitable weather win-
dow. We were lucky to get help and sound advice from a veteran cruiser (and amateur
weatherman) who had sailed this route many times before. In the end, his advice turned
out to be better than the guidance other boats received from professional routers, and we
had a very relaxed passage.
There is always a learning effect from listening to someone with more experience and
knowledge, so the need for a weather routing service diminishes somewhat over time. I
would still consider some form of experienced outside support whenever there is a risk of
a tropical system developing during a passage and/or if very narrow weather windows are
concerned. This could be a professional weather router or a knowledgeable friend ashore
with access to relevant data sources who can do some healthy second-guessing. In either
case, I would want someone with actual sailing experience in the relevant sea area whom I
could talk to over SSB rather than simply receiving emailed forecasts from sources
without firsthand knowledge. Unless emailed forecasts are very detailed and highly cus-
tomized, I feel you miss a lot by not being able to interact with the weatherman, to ask
questions and understand their reasoning. Simply providing the current conditions at our
position to the weather router may influence his or her evaluation of the forecast data she/
he is looking at. In the end, it's always your own judgment and your own decision what to
do with the advice, and that becomes more difficult the less you understand the rationale
behind the advice. Besides, you're missing out on a learning opportunity.