Tag: online

Which North are you? North 1 or North 2?

Scientists struggle to model the movement of the magnetic north pole. In our live, online ASA 105 coastal navigation course, a real instructor teaches you about this, and why you can basically ignore it.

We’re having a lot of fun with our “Live 105” classes on Zoom! Real instructor, real time, real students – in the same, small manageable class sizes we have for in-person courses. One of our current students sent a link to a BBC article related to the content of a 105 course, which is of course all about…

COASTAL NAVIGATION.

The link Cristina sent? A BBC piece about the movement, or wandering, of the magnetic north pole. We link to the piece at the end of this Rant. For now…

In that pic: the thin aqua line traces the approximate motion of the magnetic north pole from 1840 to 2019. It’s accelerated recently, creating a scientific buzz. (Pic is a still frame from a video in the BBC piece we link to below.)

THE IDEA: the magnetism of earth is both consistent and inconsistent. Compasses point to the same place on earth with minor wiggles. This is close to the geographic north pole, or the rotational axis of earth. If Atlas stopped shrugging, and spun earth on the tip of his finger like a Harlem Globetrotter, it would be on the South Pole, with the North Pole exactly at the other end – or “top.” But, “top” is arbitrary, ain’t it? Space has no direction. We’re floating in space. And, what’s more…

It might flip! Yup. Magnetic North and South have reversed from time to time. Maybe every few hundred thousand years. The question is whether this could happen within our lifetimes. And, partially due to accelerated movement of the Mag North Pole, scientists suspect it might.

1, 2, 3… SWITCH! Oops…

THE ARTICLE’S PATH: Scientists studying this have noted the acceleration of the drift of the Mag North Pole recently, and have updated the global model used for that as it relates to GPS, which is critical to precise navigation. That’s not always super critical itself; as we teach in Start Navigating ( ASA 105), it’s almost more important to check progress in real time than plan the path perfectly to begin with. Basically, they think they’ve identified two molten “hot spots” in the earth’s outer core that are having a tug of war over the magnetic north pole. Kewl! Or, very hot…

That gets into some chart nitty-gritty: the compass rose. It’s a tool to measure direction, and it looks pretty kewl too. Check it…

In that pic: a section of the 12363 chart of Western Long Island Sound, with City Island (“City I”) on the right, which is home to the Sailing Center. It’s about half the length of Manhattan away from it; northern MannyHanny is on the bottom left of the chart. It has a nice, large compass rose, or rings that measure direction. The outer ring is for true, or geographic, north – with a star at the top for Polaris, the actual North Star. The inner ring is for magnetic north, which is where compasses point more or less. In navigation classes, we teach how to use these to plot out a course to steer a boat.

THE CONVENTIONAL WISDOM: look at the annual increase/decrease in the variation as listed in rose (the pic below blows it up for you). It’s usually a few “minutes” a year. Each minute = ..? It’s a measly 1/60th of 1 degree of the compass. Yup; slicing hairs with razor blades. Anywho… if your chart is out of date, the idea is to multiply the number of years of ‘stale’ by the number of minutes of change, and add or subtract accordingly. And, get the +/- right!

ABOVE: blown-up crop of the compass rose from the same chart above. Variation: 13 degrees West as of 2016. Annual decrease: 2 minutes (2 out of 60, with each compass degree having 60!). Splitting hairs…

NYSC knows better… our Director and HBIC (Head Bozo in Charge), Captain Card, had a suspicion about something years ago. He compared every training chart the government produced, which are all frozen in time going back a far as the early 1980’s, to the updated, real-life versions of those charts. The conclusion? It’s silly to try to project any annual increase or decrease into the future. We expand on that and reveal the goods in class, and in our own in-house text book that we supply to students (and sell on the side). Despite what other books say, just skip this step. Much smarter move: get a current chart, for all the more obvious reasons.

Maybe we’ll be lucky (?) enough to see the poles flip in our lifetimes! Will planes drop from the sky, and cars run off the roads? Well, if they can’t figure that their GPS and compasses are basically pointing backward, we can’t help them.

Your takeaway? Use updated charts to plot courses to your destinations, and casually follow along with the progress of Mag North Pole’s wanderings across cold areas most of us will never visit.

And now, as promised, the link to the BBC piece…

https://www.bbc.com/news/science-environment-52550973

Happy hunting!

Newton, Navigation, & the Plague

What would Newton do? (In a modern day pandemic.) Well, he actually did it, if one considers London’s Great Plague of 1665-66 modern enough. He did several things in fact.

Isaac Newton, eventually Sir Isaac, basically quarantined himself during this catastrophe, having recently completed undergraduate studies at the ripe old age of 23. He, like all privileged Londoners at the time, fled the city. At his family’s countryside retreat, he was a busy boy! What did he do that was relevant to navigation?

Newton, with some social distance from an apparently alarmed observer, as he experiments with prisms to understand the composition of light. Image shamelessly copped from stock.)

Well, truth be told, that’s a stretch – but we do need to stretch our imaginations to keep ourselves occupied during our social distancing and quarantining. We’ll try to get there. First, here is what Newton did with his time:

  1. He studied gravity. Yep; that apple crap. This led to his eventual creation of the laws of motion and his career-defining work, Principia.
  2. He started working on optics, proving that “white” light consisted of the complete color spectrum using a pair of prisms;
  3. He picked up where Descartes and de Fermat left off with universal equations of fluctuating quantities, solving that dilemma with a series of papers and formalizing what we now call Calculus!

That was Newton. And that was then. And now, we have to find things to do and learn while keeping social distance and isolating. One option: Start Navigating SM: ASA Coastal Navigation (105). But we have to do it with social distance. So, we have to do it from home via Zoom, FaceTime, etc. That’s the Staples part (where we get some of our 105 supplies); that’s easy.

But what about the math? Newton did some complex math during his tenure away from town. How much math is involved with Coastal Navigation? That depends on who you learn it from. It can be fairly complicated – or, you can do it our way:

Plot the path without the math!

Path; no math. No arithmetic or math used to plot this set & drift ‘triangle.’ The geometry is built in. This is our preferred method. Cuz, you know… trig sucks on a boat! 1210 Tr chart (training; not updated), Block Island to Martha’s Vineyard. This is the solution to a practice plot submitted to us to refresh a memory on this technique.

We use as little math as possible when doing – and teaching – navigation. We teach the little bit of algebra needed for deduced, or ‘dead,’ reckoning, and we make it easy with a visual aid that’s intuitive to use. We refresh peeps on their long-hand division when they forget how. Can’t rely on a calculator on the water. But for the serious stuff? Set and drift of current while underway with no current tables to consult?

That’s where we plot the path without the math. Not even basic arithmetic. Just draw lines based on the concept, representing what the boat and the current do, and measure the final answer: course to steer! We even give you some toys to play with in the process…

People plotting in one of our Start NavigatingSM courses this past winter. Pre-Corona. He’s working with a triangular protractor, or plotting tool. She’s manipulating the world’s finest one-handed dividers. Yes; she’s using two hands. Sometimes that’s helpful to set one point quickly and accurately. Then one rocks ’em with one hand! All being done on a real chart, not a training chart frozen in time to the 1980’s with incorrect coloring and needless extra clutter.

Here’s how it works – think of it as a sample of the 105 Nav course. Yes, it’s an advanced topic; no, there will be no quiz to you as the reader afterward, and I’m sure you can follow along!..

Step 1: Draw a line from “point A” to “point B.” That’s the path you want to sail. It’s like drawing your own road on a map; your only job after that is to stay on it. In the chart pic above, it’s the top line labeled “DR Course” (not A to B, but think of it that way).

Step 2: Now, draw a line from point A showing the path the current will flow. How do you know? Let’s just assume you knew how to look it up and find its speed and direction. (Yes, we teach you all that in the course.) Draw it in that direction, for the distance it moves in one hour. Tool used? Any straight edge such as a ruler, or the nautical plotting tool we send you in advance! Distance? Use the dividers, or nautical drafting compass, to mark this. (No math – we promise!) In the chart pic, it’s the bottom right line labeled “Set/Drift.” So, for example, if the current is 2 knots, set the dividers to 2 nautical miles – the distance it flows in one hour.

That shows were your boat will be if you just let it drift helplessly from point A for one hour. We don’t want that, do we? Of course not! So, we have to figure out how much to offset our course to fight the current and stay on our intended track. How?

Step 3: Figure out the boat’s speed in knots (nautical mph). Then, we set the dividers to that speed. How? Same as with the current in step 2 above. It’s all based on one hour: an hour of the current’s motion, and an hour of sailing (or motoring) while in that current.

Step 4: Now, set one point of the compass/divider on the spot where the current line ends. Swing the other end over to the DR, or nautical road map line, you drew from A to B. Set the point down; draw in that line. In the pic, that’s the third leg of the triangle formed, labeled “heading” and “boat speed.”

Step 5: Boom. That line is also the angle to steer by the boat’s compass to fight the current! Measure that with your plotting tool. Steer that when you sail, and you’re on track to point B.

Is it slightly more complicated than that in real life? No… but you do need to work up to it by starting with more basic info and practice, and then the steps above are very straightforward… just like your boat’s trajectory over ground in real life/real time to arrive at your point B!

And, yes – we can teach this to you live and interactively. We’ll do that for now; eventually, we’ll be cleared for takeoff on taking off the masks, cutting the social distance, and resuming life as normal as it gets post-pandemic. In the meantime, if Newton played with prisms, here is a prism for you to ponder navigationally…

Remember the porrtait of Newton playing with prisms? No? It’s literally at the top of…
Nevermind. Here’s a hand-held compass that’s one of the most popular models in use. It uses a prism! The funny metal thing on the right is a fancy-lad pair of dividers. Elegant but not as practical as the ones shown above. We teach you how to use a hand-held compass like this in the course.

For a nice piece about one author’s current state of isolation in the context of annus mirabilis, or year of miracles (yup, that’s what they called Newton’s time), here you go… https://www.washingtonpost.com/opinions/2020/03/20/newton-formulated-his-theory-gravity-time-plague-we-need-miracle-too/

For a bit more context and detail on Newton’s topics above, check out this one… https://www.biography.com/news/isaac-newton-quarantine-plague-discoveries

And, finally… for more about finding your path on the water, and our on-line navigation course, see our Coastal Nav page here…

Start Navigating (Coastal Nav/ASA 105)