How To Use Proportional Dividers

How to use dividers

by Chris Riley Updated on November xviii, 2021. In Navigation

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How to utilise dividers

Using dividers and the latitude scale on your chart, you are able to measure distance in nautical miles. (Remember, exercise non apply longitudes to measure out distance. Longitude lines converge at the poles and the distance between them changes relative to your position on the earth.)

One minute equals i nautical mile. Examine the scale of your chart. In these examples, our nautical chart is in degrees and minutes.

Place i betoken of the dividers at position A and the other bespeak at at position B. And then, maintaining the spread, measure the altitude using the latitude calibration. In this case, the distance is 15 minutes or 15 nautical miles. Always use the latitude scale located in the aforementioned horizontal region that you are measuring.

Walking the dividers enables you to measure distances greater than the span of your dividers.

You can either depict the line or use a straight edge to guide the dividers.

To mensurate, set the dividers to a whole number, in this case we use 12, and walk the dividers along the line.

The distance between the buoys is 24 nautical miles (two steps of 12 miles each). Only it doesn't always work out and then evenly.

Here nosotros adjust the last step of the dividers, mensurate the altitude, and add information technology to the cumulative total of previous steps. We only had ane previous step in this case so the distance measured is 12 plus 7.75=19.75 miles. If we had stepped the dividers two times earlier adjusting for the final measurement, the distance measured would have been 12 plus 12 plus seven.75 or 31.75 miles.

Non All Dividers are Created Equal

No doubt you've noticed that navigation dividers look an atrocious lot like a compass used in drafting or math. At that place are diverse calipers and dividers used in numerous industries, in fact. Doctors use them, engineers utilize them, and more.

In practical terms, some of these dividers are easier to employ than others. And at sea, many boaters have come with some faster and easier solutions to using them.

Many traditional navigation dividers can be a petty stiff or clunky. Non all, but some are designed that mode. They're best used with ii easily on flat basis. Basically, you want to employ them before you head out to see. Just what near on the water? If you're doing some commercial angling, for instance, and demand to mark expressionless reckoning positions. What now? A traditional set of dividers may be too clumsy to employ in the moment. If y'all're looking for instant numbers, you need a tool that works in ane hand. Enter the drafting compass.

When you're dealing with fix intervals as brusk equally two minutes, speed is as important as accuracy. A drafting compass tin can do that. Information technology's lightweight simply authentic and reliable. Await for one that'southward at least vii inches long. A well made compass will take a loftier quality set screw that allows y'all to secure the legs. That ways looking for professional quality. A schoolhouse quality compass volition not work. Await for ones used by professional person draftsmen or architects.

A good drafting compass will let yous to locate position by radar tangents extremely chop-chop. In just seconds, really. You can plot breadth and longitude with your GPS quicker as well. Arguably, plotting time can exist cutting in half.

Drafting compasses accept a minor pencil pb in i leg. That allows you lot to piece of work faster than fumbling back and forth with dividers and a pencil. If speed is cardinal to plotting course and other navigation points, give it a try and see what you lot call back.

Almost Chris

Outdoors, I'g in my element, especially in the h2o. I know the importance of being geared upward for anything. I do the deep digital dive, researching gear, boats and knowhow and love keeping my readership at the captain of their passions.

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