Welcome to On the Go Navigation
This is a series of blog postings linked together that is designed as a companion to a series of workshops I give on navigation, mainly intended for sea kayakers. The prototype workshops were given in the winter of 2014 to members of the North Shore Paddlers Network (www.nspn.org).
Here is a table of contents of posts - each line should be hyperlinked to the topic.
Introduction (this post)
Static theory of the tides (advanced, can be skipped)
There are many different kinds of navigation: an Inuit hunter in the barrens of Canada, a hiker bushwhacking through a deep forest, a Polynesian sailor in the Pacific. What they all have in common is the need to constantly assess their position against some known land/seascape and evaluate their progress toward a destination.
This group of posts is mainly intended for an audience of sea kayakers, so we'll dispense with celestial navigation and all the non-critical elements and just focus on the map-and-chart work necessary for coastal piloting and navigation.
The figure below illustrates the feedback-loop of how one evaluates progress on a journey. Typically one starts a journey from something called a point of departure. This is a place where you unambiguously know your position. As you move on the journey, any time you find your position it is called a fix. The process of position fixing can be as simple as identifying nearby landmarks, or can involve more complicated steps. The next step is figuring out where to move, in other words, what's the speed and direction of travel. As the travel goes on, then you wish to update your progress by asking yourself how well your plan for a leg of the journey is progressing against reality, so you can update the information you're using.
One take on the feedback loop of navigation as practiced while on a leg of a journey.
The series of posts here stars off with basic chart-and-compass work that assumes you have good visibility. I then move to the topic of dead reckoning - finding position from a history of travels. This is an important skill to practice as it can come in handy when fog rolls in. I then turn to the issue of using vectors, which is helpful both in dead-reckoning and dealing with currents in crossings. Finally, I discuss tides and tidal currents, and how to handle them.
Strategies versus dogma
It's important to realize that there is rarely one right way to accomplish tasks. There can be multiple solutions and viewpoints that can work. I try to present some of the alternatives. One example is in dealing with magnetic variation. There are three possible ways of taking this into account: a) draw magnetic lines on a chart yourself, b) offset the compass needle by the amount of variation, and c) add or subtract declination. Any of these three will work, but often people are exposed to only one and feel that this is the "correct" way, as opposed to one of many.
To GPS or not to GPS
I don't discuss GPS usage in these posts mainly because there are a lot of different GPS devices out there, and, although I've used them, I'm not an expert on them. I do know people who do most of their navigation by GPS, and it can be quite precise. I tend to be a chart-and-compass kind of person, but I certainly don't disparage GPS usage. Often times, redundancy in navigation can be very helpful. Having the ability to do chart-and-compass navigation and having a GPS receiver, and knowing how to use it can give a peace-of-mind, but both have to be practiced to gain some facility.
Magnetic versus true north
I start out the course using magnetic north as the local reference for compass work, mainly because it simplifies the discussion. As I get more into it, I bring in how to figure the difference between magnetic and true north.
The starting point for this series is on how to prepare a chart to have easy magnetic north references on it. This is the next post.
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