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Done Dreamin' 10/14/06: Equatorial current and weather

P
poohwen@comcast.net
Mon, Oct 16, 2006 1:42 AM

#126 NOW October 14, 2006  0140 (UTC -10 hours Hawaii Standard Time)
N09034 W158008,  Temperature 81,  Pressure 1006 mb,  Course 0030 magnetic
Wind Variable @ 3-5 knots Seas: 3 to 4 ft swells from SW, Para-vanes down,
Miles Completed 349, Miles to Go 618, SOG 5.8 kts average.  1500 RPM

Good Morning,

Go North Old Man.  And that is exactly what we
are doing.  With a heading of 3600, Done Dreamin'
and crew are making steady progress to Hawaii.
The familiar Southern hemisphere stars are
sliding below the horizon and the Northern ones
are coming into sight.  It has been very
interesting to watch the ever-changing weather
and sea conditions as we make our way.

For those of you that may be plotting our course
on a map, you may have noticed that we have
drifted slightly right of course.  Let me
explain.  About 7 degrees N latitude we ran into
the very strong (about 2 knots) Equatorial
Counter Current.  This flows from the west
towards the east.  Rather than put a big heading
correction in to hold our GPS course over the
ground, I put the auto-pilot in Auto (heading
mode) of 3600 and let the boat gradually drift
about 6 miles right of course.  This gave us a
better SOG since I did not have a big correction
angle.  Now that the current has almost
dissipated, we are slowly drifting back on
course.  Overall, a net gain in distance traveled
to our destination.

Another interesting subject is the weather.  We
have been receiving wonderful weather FAX charts
from Hawaii.  These come through the HF radio as
audio signals and with the aid of software (Mscan
Meteo) is translated into FAX charts.  These are
very high resolution and provide a great deal of
information.  We can also receive GOES
satellite cloud-cover pictures of the entire
Pacific.  Of course, all this information is very
familiar to me, as it is basically the same thing
I have been using for the past 40 years while
flying.  I hope I am not boring you with all this
technical stuff, but I must share how this
weather is affecting our passage.

We are presently in the ITCZ (Inter Tropical
Convergences Zone).  This is an area just north
of the equator where the Southeast trade winds
meet the Northeast trade winds.  As you might
imagine, these hot humid winds create a bit of
stir around this area.  If you look at a pressure
FAX, you will see one low-pressure area after
another progressing from east to west along the
ITCZ.  These can develop into tropical
depressions, tropical storms, and even
hurricanes.  Right now, we have a tropical
depression about 200 miles off our port bow.
This counter clockwise flow has been giving us
steady S to SW winds which have been pushing us
along.  In addition, it has broken up the NE
Trade winds further to our north, which will be a
help.  The trick here is to get close but not too
close to the low, as the winds near the center
are 30 to 40 knots.

Well for the rest of you who could care less
about the marvelous workings of meteorology, we
enjoyed some chicken broccoli over rice for
dinner.  Well, I did anyway; Im not sure Mike
did.  He has been having some stomach problems.
However, this has not changed his enthusiastic
personality, or his game of Yahtzee.

Life is a Cruise,

Larry and Mike

Larry Rick
Done Dreamin'
Nordhavn 40 #33
Site: http://gricknet.homedns.org/Dads%20Web/doneDreamnHome.htm

#126 NOW October 14, 2006 0140 (UTC -10 hours Hawaii Standard Time) N09034 W158008, Temperature 81, Pressure 1006 mb, Course 0030 magnetic Wind Variable @ 3-5 knots Seas: 3 to 4 ft swells from SW, Para-vanes down, Miles Completed 349, Miles to Go 618, SOG 5.8 kts average. 1500 RPM Good Morning, Go North Old Man. And that is exactly what we are doing. With a heading of 3600, Done Dreamin' and crew are making steady progress to Hawaii. The familiar Southern hemisphere stars are sliding below the horizon and the Northern ones are coming into sight. It has been very interesting to watch the ever-changing weather and sea conditions as we make our way. For those of you that may be plotting our course on a map, you may have noticed that we have drifted slightly right of course. Let me explain. About 7 degrees N latitude we ran into the very strong (about 2 knots) Equatorial Counter Current. This flows from the west towards the east. Rather than put a big heading correction in to hold our GPS course over the ground, I put the auto-pilot in Auto (heading mode) of 3600 and let the boat gradually drift about 6 miles right of course. This gave us a better SOG since I did not have a big correction angle. Now that the current has almost dissipated, we are slowly drifting back on course. Overall, a net gain in distance traveled to our destination. Another interesting subject is the weather. We have been receiving wonderful weather FAX charts from Hawaii. These come through the HF radio as audio signals and with the aid of software (Mscan Meteo) is translated into FAX charts. These are very high resolution and provide a great deal of information. We can also receive GOES satellite cloud-cover pictures of the entire Pacific. Of course, all this information is very familiar to me, as it is basically the same thing I have been using for the past 40 years while flying. I hope I am not boring you with all this technical stuff, but I must share how this weather is affecting our passage. We are presently in the ITCZ (Inter Tropical Convergences Zone). This is an area just north of the equator where the Southeast trade winds meet the Northeast trade winds. As you might imagine, these hot humid winds create a bit of stir around this area. If you look at a pressure FAX, you will see one low-pressure area after another progressing from east to west along the ITCZ. These can develop into tropical depressions, tropical storms, and even hurricanes. Right now, we have a tropical depression about 200 miles off our port bow. This counter clockwise flow has been giving us steady S to SW winds which have been pushing us along. In addition, it has broken up the NE Trade winds further to our north, which will be a help. The trick here is to get close but not too close to the low, as the winds near the center are 30 to 40 knots. Well for the rest of you who could care less about the marvelous workings of meteorology, we enjoyed some chicken broccoli over rice for dinner. Well, I did anyway; Im not sure Mike did. He has been having some stomach problems. However, this has not changed his enthusiastic personality, or his game of Yahtzee. Life is a Cruise, Larry and Mike -- Larry Rick Done Dreamin' Nordhavn 40 #33 Site: http://gricknet.homedns.org/Dads%20Web/doneDreamnHome.htm