Marine Glossary

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route

"Route," like the term "course," is used in different ways by navigators, nav apps, and textbooks, but both are basically what they would seem to be despite their nuanced differences.

The basic concept of a route is a sequence of waypoints that lay out a desired course from A to B. A route can be defined using a paper chart or more often these days with an electronic chart navigation program. Once the route is designed in a computer program, it can be exported as a GPX file and then imported to other devices, such as a console GPS Chart Plotter (main ship's navigation system) or into hand-held GPS units for backup. It is usually much easier to design a route in a computer program with digital tides and currents at hand, than it is in the ship's navigation system itself.

It is fundamental to navigation to always have an intended route defined and being followed. Sailing without a route, is not navigation, is it just out sailing. It is not adequate to just have an active target waypoint assigned that you navigate toward. That is not a route. A route takes at least two waypoints, so you have a well defined leg between them that marks the path you want to follow. With just one active waypoint you can keep the boat headed toward it as you slip far off to the side, because you do not have a reference leg to keep track of.

See waypoint.

A paper or printed backup of a designed route is called a route plan. It is good practice to always create a route plan once the route is designed. See route plan.

In the nav program qtVlm the above concept of route is called a pathway, and the term route is reserved for a pathway with an assigned means of propulsion in specific conditions on a specific date and time, along with certain navigation rules. A sailing route, for example, is specific to a particular polar diagram and a particular wind forecast, along with such rules as always stay on the favored tack or gybe (called BVMG), or stay always on the great circle heading to the next mark regardless of the speed you end up with based on wind and polar (called GC). A route under power depends on selected engine speeds and forecasted tidal or coastal currents. Or you might have a qtVlm route that combines sailing and engine, meaning sail by wind and polar unless the speed under sail drops to a certain value in which case the engine is turned on for a given speed.

In other words, a qtVlm route is not just the series of waypoints that must be crossed—that is called a pathway plan—it is the actual track of how you would get one waypoint to the next in the prevailing conditions.

The "route plan" for a qtVlm route is not just the pathway plan denoting the locations of the waypoints, but the actual anticipated track, itemized by time interval steps or by a threshold course change, such as an entry whenever the COG changes by 10º. This anticipated track (qtVlm route plan) is obtained from the Route logbook tab on the route set up screen.