Galapagos to Marquesas -Not a Straight Line

We are a few days into this long passage and all is well. The ocean is remarkably calm and we are plodding along. I say plodding since we have not yet seen the favorable current that we expected. We are making about 130 miles per day, but we are hoping that number will increase when we find the west-bound current. We did get one report over the SSB that there was good west-bound current at 1 degree north (above the equator), but since that would cost me fuel and another bottle of champagne, we are continuing along.

Some of our more observant Dear readers may have noticed that the Shiptrak red dots are not exactly in a straight line. Even though I have not yet seen them, I would expect them to be in a gentle upward arc (like a smile) that will become more evident as we progress. Since we all learned in basic geometry that the shortest distance between two points is a straight line, is this a sign that the captain is lost or has at least lost a few of his marbles?

I assure you that this is not as it appears. Somewhere buried back in my geometry class, I learned that a Great Circle is a line formed when a plane passes through 2 points on the surface of the sphere AND the center of the sphere. Most of the nautical charts and maps we look at are called Mercator projections. This is a technique that map makers use to show a sphere in a flat rectangular way. While accurate at the equator, distances are distorted as you move north or south towards the poles. A Great Circle line appears curved on Mercator projections even though it is the shortest distance.

For any Dear readers who have not yet fallen asleep, there is a type of chart called a Gnomonic projection where a Great Circle would appear as a straight line, but they are not too common.

In any event, this captain will entertain any notion or theory that will make this 3 week passage a bit shorter.

Tom