course relative to bearing help ?

[Catfish]

Hello,
hope i don't bore you :hmm:
This is really simple, but you have to get used to it.
For developing a torpedo solution the absolut bearing (from North or whatever) is not important. This is because all the torpedo (or better the settings) need to know is where the enemy ship is relatively to you own U-boat. So your boat is the
center of everything.

Absoute heading (on the chart): This never changes, altogether there are 360 degrees around a circle, North is 000 or 360 degrees (same here), East is 090 or 90 degrees, South is 180 degrees and West is 270 degrees. Always.
(Hrrm, there may be magnetic deviations, but not in SH3, and even then you have a gyrocompass that does not depend on magnetism.)

If you are heading Northnortheast the absolute course on the map you travel at what course ? Northeast would be the middle from 0 to 90, so 45 degrees. Northnortheast is two parts north and one part East, so you travel at 030 or 30 degrees.

OK, we just said this does not matter setting up a torpedo solution

Standing on your U-boat's conning tower this boat becomes your center of the universe. Your bow always points to zero, or 0, or 000, or 360 degrees. Imagine standing on a ship's deck and you see something to your right. You could yell "something on the right", but unless it is not at 090 degrees this is not very exact.

Were you in a plane you would yell something like "enemy at 3 o'clock high" which would be an enemy plane at 090 degrees and higher relative to your own plane (which's nose again would be 12 o'clock). However we are at sea, and us mariners use the 360 degrees circle, not the 12 o'clock circle, and certainly do not bother
with high or low

So if a watch wants you to tell something like a sighted ship he takes the U-boat as the reference system, and tells you the position of the other ship relatively to your own boat's course - beginning to count at the bow with 0 until the sighted ship appears. This is the course of sight relatively to you ship, or better relatively to your ship's course.
What is confusing here is that they talk about "course". You have to understand that every angle or direction is called a "course" on a ship. If a ship appears to your left your watch will shout "ship at 270 degrees!", and he could as well shout
"ship course 270 degrees!". The enemy ship's own real course does not have anyting to do with it.

Hmm, does that help ?

Greetings,
Catfish

[flag4]

hi Catfish

thank you for your explanation. i understand the clock affect as the degrees go round the compass; if my WO calls out ship spotted at 90 degrees i know he is on my right which ever way im heading...

what im struggling with is demonstarted in OLC's tutorial when he plots a course parralell to a ship on his left. WO calls out ship spotted bla bla bla degrees. ( i cant remember the exact course im at a different computer..)

he then enters the information on to his nav map and - this is the bit im stuck with - draws a line from his boat to the ship using his protractor, clicking first on his course then his u boat then extends this line out towards the ship to about two thousands yards, where his WO spotted it

there is an angle he comes up with like 53 degrees from his boat to the ship - this then pin points the ship.
and if he didnt have his ship contacts turned on ( the little black squares.) the ship would be at the end of this line/angle.

do you understand me ?

how does he arrive at this angle. its something like 360 - degree of spotted ship = 53 degrees.
and i believe this changes whether a ship is port or starboard. its either subtract or add.

tell me what you think - do you understand me? if you watch OLC's tutorial you will see what i mean - i may not have expalined it very well.

thanks
flag4

[bert8for3]

From what you're saying, I think OLC must have been marking a reported bearing to the target using the protractor tool. The tool unfortunately does not mark bearings in straightforward 0 deg through 360 deg, but rather in 0 to 180 going starboard (right) and 0 to 180 going port (left). If he marked the protractor line out on 53 deg to port (left), the reported bearing must have been 307 deg, which for using the protractor (for port or left side bearings) has to be translated as 360-307=53. If the bearing was starboard (right) it would have been reported simply as 053 deg and you would just lay off 53 deg (right) with the protractor.

[wizardmatt]

Hi OP.
This link could be helpful:

http://www.paulwasserman.net/SHIII/

It is a tutorial on charting and plotting, as suggested by the "newbie guide" stickied thread above. Ive found it VERY helpful; its described somewhere as "essential reading", and it addresses exactly the issues youre talking about, with helpful diagrams.
you can if you wish download the guide: HOWEVER, the last time i tried the link for the download at wazoo's site, it didnt work, so i just googled something like "wazoo sh3 manual plotting charting guide download" - i now have it in my documents!

EDIT: here you go:

www.finael.fr/sh3/charge/charting_&_targeting.doc

good luck!

[flag4]

bert8for3

you understood me !!

i kind of see what you mean. it will take a while to use it smoothly with out doubt or cock-ups but i will get there.

and thanks to you wizardmatt i will be able to study it in a bit more depth.
i know the navigation tools have developed quite a lot since wassermans tutorial but i think i can suss out whats relavent to using olc's today !!

many thanks for your help.
flag4

[wizardmatt]

youre welcome