Data from Other Yachts
It is the norm
now on most passages to be sharing your part of the ocean with
a number of other yachts.
Often these yachts
will check in to a "net" on either
ham or SSB frequencies,
giving their position, barometer reading, cloud cover, wind
strength and direction.
If you log this
data, you can then begin to construct a highly accurate picture
in your mind of what the weather is doing.
Some years ago
Linda and I were in Fiji, ready
to head for New Zealand.
Beowulf was new at the time, and we were taking her to
Auckland for her interior.
This was the last
leg of our trip and we wanted a really good blow as one final
test.
We sat in
Malololailai for two weeks watching fax charts from
New Zealand, Australia,
Honolulu, and Rarotonga.
All of these fax charts were derived from the same raw satellite
data using different computer models--and they all differed
substantially from each other.
At the same time,
several dozen yachts were en route to
Bay of Islands, New Zealand
from Tonga and Fiji, all checking in with
Keri-Keri radio.
By plotting their
locations and reported conditions, it was easy to see what the
real picture was-- a high pressure was moving in from the
Tasman, winds were light and, unfortunately, we expected
them to stay that way.
Sometimes there's
just one other vessel out there. If it happens to be between
you and a brewing weather system, they can serve as an early
warning service for you.
One thing for which
you do need to make allowances is the accuracy of the other
boat's barometer. It may be off
several millibars if it hasn't been calibrated making the absolute
reading of small value.
However, the
relative reading -- how much the barometer is rising or
falling, and over what time period -- is still significant.
