How do we use the usual compass?

Question

apart from knowing the geographical directions

Answer 1

Firstly, it must be corrected for the magnetic variance in your ares of use. This can be done by motoring directly at and away from landmarks noted on your charts...this is called a "range".

You need to note the charted angle from the chart by extrapolating the measure from the "Compass Rose" on the chart. Compare this to the reading from your compass while traveling the range to the landmark. The difference is the amount to be corrected. Write this on your chart or in your logbook.

You can adjust your compass but most just check annually as the variance changes every year. Simply be mind full of the addition or subtraction needed for headings and bearings when navigating.

Basically though....you need to familiarize yourself with the charts and the Compass Rose. Also get a "Chart Kit" of dividers, slide rule and walking rule and protractor so you can extrapolate lines from the rose and set a coarse. You then use your compass to follow that coarse.

Answer 2

A fixed compass on a boat will show you which direction you are heading. I suggest that you need some Navigational instruction from a boating school before venturing out!

Answer 3

I don't know what a "usual compass" is... To you mean a MAGNETIC compass?  If so, it will swing opposite to the way you move it.  Just look at the lubber line and move it to the left and then to the right and you will see how it works.  If the lubber line is on the center line of the boat or vehicle, then that is the direction in which you are moving

Answer 4

In addition to above use it to:

a) be able to set a reciprical course (go back where you came from) - ifyou have been on a course East you go back West - a course of 90 (E)has a reicprical of 360-90 = 270 (W)

b) (with a hand bearing compass) you can give/take a bearing to/from a known object - "St Mawes Castle is on a bearing of 120" - if you can give a bearing to two or more objects then you can plot your location (obv. not locations close to each other) on a chart.

c) you can follow a course determined from a chart e.g. 2 miles on a heading of 105 then  3 miles on 95

d) deadreckon (know where you are).  E.g. If you have travelled for 1 hour at 5kts on a haeding of 88 then with knowledge of the currents it is possible to estimate, using a chart, where you are.

This has lots of useful stuff:http://www.bananawind.us/Basic_Navigatio...