The blistering sun is relentless, the broiling heat inevitable. Not too surprising. It is summer in Mexico after all. And still my mind has wandered off to distant shores in the cold.
The book is written, I can finally take down my pen and prepare my next voyage. After the game is before the game. I have nine long months left until departure. It seems little compared to what I all need to do and learn to get prepared. Pilot charts of Greenland and northern Canada are spread out on my navigation table, the handbook “Arctic and Northern Waters” flipped open burying the “IMO Guidelines for Voyage Planning in Remote Areas” and the IMO Polar Code underneath. A bead of sweat drips on the chart staining Cape Desolation in western Greenland.
Named by John Davis in 1586 he was under the impression that he found another island different from Greenland looking for a passage to Iceland. He considered the entire area so desolate that he called that land that he believed to have found Desolation. Not as alluring as “Greenland” you might say but still intriguing: calving glaciers, untouched wilderness and icebergs sculptured by Thor’s pocket knife.
Since I have navigated the equatorial waters of Amazonia the seed grew in my mind to sail Arctic waters next. You may remember the short story “I Am not a Sissy” that ended with “… next year I will sail to Greenland. And if it is just to prove to myself: I am not a sissy.” And while the pandemic delayed my departure by a year it gives me plenty of time to get my boat and myself prepared for these high latitudes.
A Bold Idea
While at first it was just a bold idea, it’s only now that I understand how bold the idea really is. When I talk to my friends Maiwenn or André, both professional sailors who have been sailing Arctic waters for years I feel like a rookie, a greenhorn in the wild north. All my decades of sailing experience, all my miles and sea time, worth nothing more than sweet memories. I realize now that most tools we use for navigation are just approximations at best. To use them in polar areas we need to understand how they work in detail and what their limitations are.
But first of all, what exactly is the Arctic? The etymological explanation only points us towards the right hemisphere. The Greek word “arktos” for “bear” refers to the northern hemisphere stellar constellations Great Bear and Little Bear with the North Star Polaris.
What is the Arctic?
So far so good, interestingly the area that is comprised by the Arctic is not coherently defined. Whereas some define the Arctic purely geo-astronomically by the area north of the Arctic Circle (the line where theoretically one day in the year the sun never sets and one day it never rises), the most common definition is based on the 10°C-isotherm. The area with an average temperature below 10°C in the warmest month (July) are considered Arctic. This definition corresponds closely to the tree line definition.
The Arctic Ocean, the smallest, most shallow and least salty of the five major oceans recognized by the International Hydrographic Organization is to a great extend covered with ice. This was not always the case. In fact the time we live in is considered just the fifth ice age our planet has seen. Ice ages are defined as periods in which “the polar areas are permanently covered with ice sheets” which may seem surprising with the current global warming discussion going on. But yes, most of the Earth’s time the average temperature was much higher than today and the Arctic Ocean free of ice.
Ice Age
An Arctic Ocean free of ice would clearly make it easier to navigate because it’s the ice that’s imposing the most critical threat to navigation. There are two different types of ice: Sea ice and icebergs. Whereas sea ice is frozen seawater, icebergs are glacial ice formed by fresh water. So, I am learning to read ice charts and understand ice forecasts. I learn what polynyas are, big, ice-free areas surrounded by sea ice. They are formed by warmer water rising to the surface or by wind and they can be huge. Their existence was the major supporting pillar of the theory of an ice-free polar ocean, a popular theory in the 19th century that also spurred Germany’s first north polar expedition in 1868 led by Captain Carl Koldewey who still holds the record of the northernmost point reached by a sailing vessel with no engine, crazy 81°04’N!
But ice is by far not the only threat to navigation. There are more caveats that most sailors of moderate and low latitudes never even think about.
Compass
We do know that the North Magnetic Pole is different from the North Geographic Pole, and we also do know that the compass points towards the North Magnetic Pole (approximately) and we use the magnetic declination to find True North. But not only becomes the magnetic declination bigger and more variable as much as we are getting closer to the poles. The magnetic compass depends on the horizontal component of the magnetic field of the Earth. As the North Magnetic Pole is approached in the Arctic, the horizontal component becomes progressively weaker until the magnetic compass becomes useless in fact. Also gyro-compasses, that are hardly ever carried on small sailboats, are only reliable up to around 70ºN as the angle between the compass’s rotation axis and the rotation axis of the Earth becomes too big and its directive force gets lost.
Global Navigational Satellite Systems
“But who needs a compass these days anyway?”, you may ask. We live in modern times of GNSS like GPS, GLONASS or Galileo. True that but also here are some caveats. The first barrier to GPS being reliably available in the Arctic is due to the orbital inclination of the satellites involved. The satellites follow one of six orbital planes, all at an inclination of roughly 55 degrees, though some other satellite navigation systems, like Galileo and GLONASS, have higher inclinations of 56 and 65 degrees, respectively. The Arctic circle, meanwhile, is located at about 66.5 degrees north. At these high latitudes, some satellites are still visible at any given time, but they never pass directly overhead. In fact, when using GPS right at the pole, the highest elevation GPS satellite you would see is 45 degrees above the horizon. This will result in longer times until we get a fix and a lower accuracy.
Arctic Charts
This being said, it’s not the GNSS that is the real problem here. It’s the charts. Charts in the Arctic are less accurate and less complete than in other parts of the world. Some areas have last been surveyed 200 years ago, with equipment that does not satisfy today’s needs of accuracy. Also the ice coverage made and makes it difficult to gain good geodetic data. And last not least charts of the Arctic have not yet been adopted to the datum used for GNSS systems, the WGS84. So it can easily be that Greenland’s coastlines are up to two nautical miles off the GPS position. Bold warnings on Arctic charts inform the navigator about this circumstance.
This means that even if our compass would work and we could get reliable bearings to relevant landmarks, a cross bearing may or may not put us on the right position and therefore is not reliable.
Now, what about celestial navigation? While the accuracy of charts is probably sufficient for the accuracy that is potentially possible using methods of celestial navigation we have to fight with two other problems. During the arctic summer the choice of visible celestial bodies is very limited. And during the arctic winter we probably have other priorities than determining where exactly it is that we got stuck in ice.
So, once I asked my friend Maiwenn, how she would navigate up there without falling off the edge. She said: “It’s a balance between visuals, plotter and radar. If there are berg and they are moving you’re all set. If they are big and stationary it’s probably deep enough. If they’re small and stationary it’s not good. If the seagulls are standing it’s bad.” Sounds easy, right? Who needs charts when we have icebergs?
Mercator vs. Stereographic Projection
And there is another detail that we need to say good-bye to sailing polar waters: the good old Mercator projection of charts. The closer you’ll come to the poles the more distorted it gets until it turns completely useless for navigation. So, in the pole areas stereographic projection is being used instead. Centered around the North Geographic Pole the stereographic projection represents the relative directions of all great circles passing through the North Geographic Pole. As a conformal projection, it also represents angles everywhere. In addition, in its spherical form, the stereographic projection is the only map projection that renders all small circles as circles. Luckily for my planned voyage I don’t need to get too used to this but all arctic sailors are well advised to be able to read stereographic charts.
Satellite Communication
And if you want to call home you better not rely on Inmarsat because communications satellites operating in geostationary Earth orbit like Inmarsat do not cover the polar zones. The Iridium satellite constellation can supply communications services in the Arctic, but interruptions are possible which can last several minutes.
The more I learn about Arctic navigation the more I understand how difficult it is and how little I really know about it. So, I guess, I have to use the remaining nine months well. I will also try to loose some weight. Lacking centrifugal forces and distance to the geocenter, gravitation is significantly higher in the Arctic, with the unfortunate but inevitable effect that I will gain a pound just by sailing north.
So I better enjoy the good Mexican food as long as the Earth’s geometry is still in my favor.