bearing tool confusion - please provide a master class in screen shot and paragraph !

[flag4]

once again - please !!


i'm trying to figure out the bearing tool on the f5 nav map, the pull-down one. it has two sets of numbers - an outer ring and an inner ring. the 180 degree numbers are at opposite sides of the tool. i'm trying to relate this to the position of my boat and the direction of merchant's and other desirables.

i,m trying to use it in conjunction with the hydrophones - so if i get a bearing on a merch' at 275 how do i correspond with this information to this tool - at the moment i'm flummaxed and seem to be going around in circles with all the merchants gayly on thier way.

i hope i have made myself clear - maybe a screen shot would help me - and others !

to suss this out ,

many thanks - from the duck pond

[Brag]

The tool's outside ring allows you to measure a true heading in degrees from North (360). The inside ring gives you the reciprocal.

When you use the hydrophone, you get RELATIVE bearings, that is relative to your heading. The bow being 360.

Let's say you're going east (heading 090) and a target appears on your port side (to the north of you) it will be reported as target bearing 090. But to reach it (if it's not moving) you have turn to a heading of 360.

If you plot an intercept, calculate the distance the target will travel, if you know the course, you measure with the plotter.

Then you draw the intercept course and measure again, it will give you what heading to turn to.

Try it a couple of times on the chart and it will clear the confusion

[flag4]

Brag

thank you for putting this up, i will be re-reading this over and over again, but at the moment i cant understand it - i'll print it off and put it with the expanding file i have for sh3.

"my hands reach into the fog."

cheers

[snwcrsh]

Maybe an explanation with other words help more.

There is a difference between absolute and relative bearing.

When you set a course on a compass, you set your course as an absolute bearing, i.e. 000 is north, 090 east, 180 south, 270 west as you know it.

But whenever you look through periscope, binoculars or put/gather data for the TDC it will be relative bearings. This means 000 is to the front of your boat, 090 is right (starbord), 180 stern, 270 left (port).

So as in Brags example if you are heading East (absolute bearing 090) and you encounter a ship in your binoculars at 270 (port side), it is on absolute bearing 000 (to the left of you).

The tools in the navmap will always show abolute bearings. However, there are mods that will give you a relative bearing tool on the map (it actually turns with your sub) -- i'm sure others can point you where to get it.

hope that helps

[flag4]

snwcrsh,

absolute is the permenant global fixture, relative is relative to the moving boat and its position ?

im still lost but i think i get that !!

cheers

[Antiacus]

In this example the boat is on a course of 075 absolute bearing... Due North is obviously 000 degrees absolute bearing. The radio beacon is at 45 degrees relative and the ship on his starboard quarter is at approximately 160 relative. In SH3 all contacts reported to you are given in relative bearing.


Hope that helps

[Schwuppes]

Originally Posted by Brag

Let's say you're going east (heading 090) and a target appears on your port side (to the north of you) it will be reported as target bearing 090. But to reach it (if it's not moving) you have turn to a heading of 360.

The target bearing would be 270 degrees.

[Sailor Steve]

Originally Posted by Schwuppes

The target bearing would be 270 degrees.

Exactly. To see absolute bearing (or heading) align a compass to North. To see relative bearing (to your ship) align the compass with your bow.