passagemaking@lists.trawlering.com

Passagemaking Under Power List

View all threads

East or West around?

MH
Mel Hodges
Wed, Apr 19, 2006 11:10 PM

When circumnavigating in a power boat, does it matter if you go east or
west around?

Do the winds or the currents make one direction favorable to another?

I'm talking about a voyage in a boat such as Idlewild's.

When I leave from Seattle, I need to know if I should take a right at San
Fran and head to Honolulu, or keep going south towards the canal...

thanks!
Mel

When circumnavigating in a power boat, does it matter if you go east or west around? Do the winds or the currents make one direction favorable to another? I'm talking about a voyage in a boat such as Idlewild's. When I leave from Seattle, I need to know if I should take a right at San Fran and head to Honolulu, or keep going south towards the canal... thanks! Mel
PP
Peter Pisciotta
Thu, Apr 20, 2006 4:44 AM

When circumnavigating in a power boat, does it
matter if you go east or
west around?

A quick Google search found the following list of solo
circumnavigators Sail) showing most go westward toward
the setting sun:

http://www.joshuaslocumsocietyintl.org/solo/solotable.htm

Why? Currents and winds. The Willard Boat Owner's
Group
(http://groups.yahoo.com/group/WillardBoatOwners/)
recently discussed the 1987 journey of a Willard 36
from San Diego to Hawaii (2275 nms). An archived 1987
letter from the boat's owner to Willard Marine
explained he averaged 6 knots and burned under 350
gallons at 0.9 gph. This was difficult to believe -
the W36 would have to do around 5.5 knots to burn
under 1 gph.

However, after consulting Visual Passage Planner
software (www.digwave.com), the owner's claim is
credible (VPP is an electronic version of the Pilot
Charts with historical wind/current/storm patterns for
all oceans, all months. This is the same information
Jimmy Cornell based much of his World Cruising Routes
book upon). Assuming a 5.5 knot boat at 0.9 gph, the
August weather patterns predict a bump in speed to
just under 6 knots - and burn 389 gallons, very close
to the owner's 1987 claim.

Going the opposite direction - Hawaii to San Diego -
is a different matter. The VPP model estimates the
trip takes 2-days longer, average speed drops to 5.1
knots and total fuel burn increases ~15%.

Bottom line: time of year is important as Scott Bulger
suggests, and for equatorial circumnavigations,
westward appears to be the better direction.

Peter
www.SeaSkills.com

> When circumnavigating in a power boat, does it > matter if you go east or > west around? A quick Google search found the following list of solo circumnavigators Sail) showing most go westward toward the setting sun: http://www.joshuaslocumsocietyintl.org/solo/solotable.htm Why? Currents and winds. The Willard Boat Owner's Group (http://groups.yahoo.com/group/WillardBoatOwners/) recently discussed the 1987 journey of a Willard 36 from San Diego to Hawaii (2275 nms). An archived 1987 letter from the boat's owner to Willard Marine explained he averaged 6 knots and burned under 350 gallons at 0.9 gph. This was difficult to believe - the W36 would have to do around 5.5 knots to burn under 1 gph. However, after consulting Visual Passage Planner software (www.digwave.com), the owner's claim is credible (VPP is an electronic version of the Pilot Charts with historical wind/current/storm patterns for all oceans, all months. This is the same information Jimmy Cornell based much of his World Cruising Routes book upon). Assuming a 5.5 knot boat at 0.9 gph, the August weather patterns predict a bump in speed to just under 6 knots - and burn 389 gallons, very close to the owner's 1987 claim. Going the opposite direction - Hawaii to San Diego - is a different matter. The VPP model estimates the trip takes 2-days longer, average speed drops to 5.1 knots and total fuel burn increases ~15%. Bottom line: time of year is important as Scott Bulger suggests, and for equatorial circumnavigations, westward appears to be the better direction. Peter www.SeaSkills.com