Navigating Without a Compass by Day

Your rudder steers your vessel but your compass guides your vessel!

What would you do if your compass dies? The compass could fall overboard, get affected by strong magnets, or even spring a leak and lose all its fluid. Now what?!

With paper charts, you can run out your Dead Reckoning line to see what area of the world you are heading towards if you don’t alter course; but you still need a way to make sure you are staying on a course.

By day, you have the Sun to use for navigation. By night you have the stars to guide you in the darkness of the open ocean.

The Sun rises in the East and sets in the West, roughly. Throughout the seasons there are some declination fluctuations since the Earth spins on a tilted axis. This means that the Sun will rise and set slightly South of East and South of West if you are in the Northern Hemisphere, and slightly North of East and North of West if you are in the Southern Hemisphere. Suddenly, using it as a guide begins to fail as an idea.

With an analogue watch, you can roughly figure out which way is North and South, but you are going to need some help. On land, where watches are set according to local time, all you have to do is pull out your watch and look at it. The problem is that you are out at sea, traveling across timezones, so your watch is no longer set to “local” time. Your first step will be to figure out what time is “local”.

You will need to sit around and observe the shadows on your boat. Preferably look at the shadows of your stanchions or some other small pole on your deck. You want to keep track of the shadow it casts, as the shadow will tell you which way is North at that instant and when “Noon” occurs to set your watch to.

As the sun rises and makes its way to the highest point in the sky, the shadow of such a component on your deck will begin to shorten. At it’s shortest, the shadow will be pointing North (opposite if you are in the Southern Hemisphere) and the moment when the shadow is shortest is “Noon”.

This sounds simple in theory, but it will be tricky to do and your measure of “Noon” will be rather rough since the boat is going to be moving around in the seas. If you happen to have a sextant, this measure of noon will be much more precise because you can use the sextant to find the highest position of the sun in the sky! If you had a sextant though, you wouldn’t need all these other methods because you would already be navigating!! Moving on…

You guess roughly what time is noon with your shadow trick and now you have a lowly calibrated watch that tells you the cardinal directions and is not on time with any other watch in the world! Using the watch, you can point the hour hand at the sun and look at the face of your watch. Now draw an imaginary line that bisects the angle between the hour hand and “12” on the face. If you are in the Northern Hemisphere, the bisecting line will point South and the opposite position on the watch face will point North.

If you are in the Southern Hemisphere, the opposite will be true and the line between the hour hand and “12” will be your North and the opposite side of the face will be South.

Let’s try this out in the Northern Hemisphere. It’s 6AM and the sun just came up over the horizon. You point the hour hand at the sun and look at the face.

Three points are going to be told on the face: Sun is at “6”, “12” is directly opposite so “9” will be pointing South, while “3” will be pointing North.

Now it’s 10AM and the sun is higher in the sky. Sun is at “10” “12” is much closer to the hour hand, “11” will be pointing South as it is the bisecting point on the face between the hour hand and “12”, therefore “5” is North.

At Noon, the Sun is at “12” and so is “12”, so “12” is South and “6” is North.

At 5pm, the Sun is starting to get low to the horizon. Sun is at “5”, “12” is now farther from the hour hand and “2:30” (halfway between 2 and 3) will be pointing South and 8:30 will be pointing North.

This is a cool parlor trick, but if you are sailing East or West, you will have to recalibrate your watch for the new “noon” as you will be traveling across timezones and your timely compass will begin to waver in accuracy.

Why does this work? It’s rather simple actually. If you are in the Northern Hemisphere (and not too close to the equator as during the summer, the sun actually comes over the equator which would then put you into the “Southern Hemisphere Setting” even though you are still in the Northern Hemisphere) the sun will rise in the East, set in the West, and transit the sky South of your position. At any point in the day, if you are looking in the direction of the sun you are also looking in a Southern direction. At Local Apparent Noon, the Sun will be directly South of you and any shadow cast will point due North. Therefore, as the sun rises, by tracking it with the hour hand which moves along the face of the watch at the same speed as the sun moves across the sky, you can track it’s position. Since the sun will be South of you at Noon, when the hour hand is at “12”, the angle between the hour hand and “12” will be 0 and “12” will be pointing South while “6” will be pointing North.

This lets you track the day and the sun to maintain your moving compass rose that floats around the face of the watch relative to the hour hand and “12” position.

The end result is a crude compass that will allow you to maintain a relative course without steering in circles.Now, if these concepts are familiar to you then you probably already understand the relationship between the Sun, time, and your position on the Earth. You might lose your compass, but you definitely still have your sextant secured in a safe place because the Sun is your guide and you already understand how and why a Noon-sight works.

The Value of Technology

When out at sea, the most valuable piece of equipment on a yacht today is probably the GPS Chart Plotter, not the Compass.

GPS will give you your exact position with a range of error of a few feet! The GPS antenna on our AIS is so accurate that during installation it asks for the exact position of the antenna on the yacht to know the true space that the vessel occupies on the surface of the ocean!

GPS started off wonderful, a small screen would display your exact coordinates on the Earth. You no longer need a sextant to find your rough position and Dead Reckoning just became very obsolete! The readout lets you quickly know precisely where you are so you can plot them on a paper chart and figure out where you should go next.

Then someone thought about how they could make it even easier to do! Paper charts are big and cumbersome, so this was the next point to improve upon! GPS displays grew bigger and bigger to the point that maps could be visible on them, and eventually charts could be displayed on their screens. Now your position is instantly plotted on the screen in real time right before your eyes!

Navigating transformed from an art that takes practice to a video game where you steer your little boat shaped icon around on a screen. Avoiding rocks, buoys, and day markers suddenly became possible, even in the darkness of night or the blinding effects of thick fog. This is great for stationary objects that don’t move, but what about other boats on the same waterway?

AIS makes this possible, and even better it plots the other boats on your screen! Suddenly, sailing became a video game where you can steer blindly in any conditions, all you have to do is avoid the other dots on the screen!

This all sounds rather fantastical, but the sad thing is while we were in the Azores, I met another cruiser who luckily arrived after having some technical issues with one of his motors (on his catamaran). This cruiser carried no paper charts, only chart plotters. These large screens were very apparent in his cockpit area. When off they were huge black rectangles and when on they could serve as a flashlight!

The alarming part is he did not carry a compass.

If his electronics failed or if his ability to power electronics ran out, he had no paper charts to plot his position and calculate his course or to navigate by, and even worse, he had no compass to guide him.

Technology is awesome and it has made it possible for us to sail into completely unknown ports for the first time with confidence that we will safely anchor without bumping into anything! That doesn’t mean that technology should be revered above the tried and true simple tools of the past, like a compass.

No Winter Sailing in the Mediterranean Sea

In the Mediterranean, it is common knowledge that you can’t sail in the winter. The winds are too strong and the seas are too punishing!

This is what everyone who sails there says, but most people who sail there have “only” sailed there. Bad conditions exist everywhere so it’s a bit of a stretch to say that “this is the worst”. When I read accounts of circumnavigators who sailed the Mediterranean in the winter, they did so on “good days” and said it was rough but still manageable.

So the two types of stories are: “Can’t be done” by people who haven’t sailed elsewhere and this is their first large body of water and “It’s really rough” by people who have crossed an ocean before.

Being how we have weathered a storm off Cape Hatteras and faced Force 11 winds in the middle of the North Atlantic, we felt that we could confidently manage the conditions of the Mediterranean in this winter season.

We waited for what seemed to be a calm period between punishing storms. We were in the middle of the Alboran Sea (the first sea in the Mediterranean) and the conditions became very punishing.

While the winds reached Force 10 with gusts of Force 11 and 12, the waves were only 12 feet high! The problem was that the waves were very close together and very steep, not giving the yacht time to rise and fall over the waves; instead the waves crashed over the boat with punishing blows every few seconds.

Modern European production boats with low build quality would begin to break apart from such relentless pounding, as the deck/hull joint would begin to break open and wreck the whole yacht. Most of the people who only sail the Mediterranean are also cruising on these European production boats and are wise to not venture out into the sea if they wish to return alive and with their yacht still floating! We are cruising on a very old and very heavily built yacht that can take a pounding and keep going. It’s low freeboard means that it offers less of a face to a crashing wave and its heavy construction allows it to resist such punishment.

One thing is being able to do something and the other thing is being nonsensical about such decisions. Just because your car has bullet proof windows doesn’t mean you shoot at it every time you get the chance!

We decided that enough was enough and this punishment was not necessary or worth it!

Crossing the Mediterranean in the Winter

The Mediterranean Sea is known to have very fickle winds. Think about all the old tales of shipwrecks and storms at sea; think of The Odyssey! Well, those tales are true.

In the summer, the Mediterranean is plagued by no wind, while in the winter it is plagued by gales! These gales are not called storms because a storm is strong and unusual wind that is blowing; these are just “the winds”.

We leave our anchorage in Gibraltar and make our way through the Strait of Gibraltar and officially into the Mediterranean Sea. The winds were forecasted to be following us and a bit strong, but nothing we haven’t seen out in the Middle of the Atlantic (or off Cape Hatteras). The winds started out as expected, but then the winds continued to build further and further until they were way beyond our comfort zone!

Using The North Star

You know how to find it, you know where to look, but do you know why to look?

The North Star sits directly over the North Pole and is a handy indicator at night for “which way is North” but it also serves one more very handy purpose.
The North Star tells you your latitude without any math or calculation. By measuring the angle from the horizon to Polaris (The North Star) with a sextant, you will instantly find your latitude!
Since the North Star is directly over the North Pole, this means that if you stood on the very pole itself and looked directly up, Polaris would be directly over you.
Your latitude would be 90* and the angle of observation in the sextant would also be 90.
If you were at the equator, at Latitude 0*, the North Star would be directly on the horizon (and not too clearly visible).
Therefore, every degree of latitude that you gain in the northern hemisphere, Polaris will also gain a degree of observation from the horizon.
This fact has been known for hundreds of years and in the old times (when navigation was more crude) navigation was performed with a board and a rope!

The board would occupy the void between the horizon and Polaris, and it was held a prescribed distance from the observer.
The prescribed distance was controlled by the rope, which would have knots tied in it. The observer would bite the desired knot and hold the board out away from their face until the rope went tight, then they would position the bottom of the rope so that it would lay at the horizon and the top of the rope so that it would lay at the North Star. If there was a gap between the board and the North Star, they knew they were too far north and needed to steer more south. If the Star was covered, then they were too far south and needed to steer more North until the Star was visible again. If the Star and horizon just touched the board, then they were at the correct latitude for their destination!

There was no measure of Longitude on a ship at that time so they simply sailed to the desired ports latitude and sailed East or West until they ran into it! Thankfully, the ability to keep time on a ship changed this crude behavior as longitude was then able to be calculated and the mysteries of “when will we get there” vanished!