Historical method for finding range of an unidentified target?

[Geandily]

Anyone know how they figured out range if mast height was unknown? Our ID book is a little too accurate for my tastes...

Did they simply ballpark the mast height based on known averages and then calculate range from that? I don't think hydrophone and sonar were something the UBOATs used to find range...
Would range have simply been guessed at once course, speed, and AOB were known?

[Dewgle]

There's a few different methods. First is sailing in front of or behind the target to capture their course-line when observing the ship at an AOB of 000/180.

If AOB is 180° then the true bearing to the target is their course. If AOB is 000° then add/subtract 180 from the true bearing, etc. Then once you have their course-line plotted on the map, any bearings you take just drag them to the pre-existing course line and that's the range!

Another method requires that you know the target's speed, but that's easy. Just run parallel to the target and keep adjusting your speed and course until they are neither moving closer or away in your periscope, nor moving to the left or right. 'Standing still' in your scope is what you want. Now you know their course and speed because it matches your course and speed.

Now take a bearing while simultaneously starting your stopwatch, then stop your boat and wait. Wait as long as you like, in fact the longer you wait the more accurate the test results will be. Take a 2nd bearing in sync with stopping your watch.

You know how fast they're going so you also know many meters they should have traveled in that length of time. Now you just have to make that length of ruler 'fit' within the two bearings you took.

This becomes a bit easier if you draw an imaginary 'bearing' line from where your boat would have been had you not stopped when you took the 2nd bearing.

[Dewgle]

Are you on the Discord? I can jump on stream and show you

[wolf310ii]

With the 4 bearing methode.

https://www.youtube.com/watch?v=z2nr2G2SRGY

[Geandily]

Originally posted by wolf310ii:

With the 4 bearing methode.

https://www.youtube.com/watch?v=z2nr2G2SRGY

Cool video. I want to play modded SH5 more! That's definitely a great method but I thought 4 bearings method wasnt done until after WWII?

McDewgle I want to join the discord at some point, have just been busy! I acquire course and speed in the same way as you say. I have been ballparking range which works well enough but would like to learn that visual bearing method for a more accurate range. From your post I think I can probably figure it out

thanks to both of ya :)

[Dewgle]

I am told by many subsim and WWII historians that the 4 bearing method had not been developed until after WWII. Which is why I avoid teaching it anymore.

[Dewgle]

I also stream tomorrow 11:00est/15:00utc on Twitch.TV/McDewgle where I can host a tutorial on easy & historical methods

[athenian]

Originally posted by McDewgle:

I am told by many subsim and WWII historians that the 4 bearing method had not been developed until after WWII. Which is why I avoid teaching it anymore.

Oh I wasn't aware of that

[Geandily]

Originally posted by McDewgle:

There's a few different methods. First is sailing in front of or behind the target to capture their course-line when observing the ship at an AOB of 000/180.

If AOB is 180° then the true bearing to the target is their course. If AOB is 000° then add/subtract 180 from the true bearing, etc. Then once you have their course-line plotted on the map, any bearings you take just drag them to the pre-existing course line and that's the range!

Another method requires that you know the target's speed, but that's easy. Just run parallel to the target and keep adjusting your speed and course until they are neither moving closer or away in your periscope, nor moving to the left or right. 'Standing still' in your scope is what you want. Now you know their course and speed because it matches your course and speed.

Now take a bearing while simultaneously starting your stopwatch, then stop your boat and wait. Wait as long as you like, in fact the longer you wait the more accurate the test results will be. Take a 2nd bearing in sync with stopping your watch.

You know how fast they're going so you also know many meters they should have traveled in that length of time. Now you just have to make that length of ruler 'fit' within the two bearings you took.

This becomes a bit easier if you draw an imaginary 'bearing' line from where your boat would have been had you not stopped when you took the 2nd bearing.

After re-reading this a few times I think I get exactly what you mean. Really good description actually thanks again.
I might pop by your stream @_@