Historical 2x3 bearing only method in 1941
 

Dunno if anyone noticed this but in 1941 US Navy Maneuvering Board Manual, there's a bearing only method in case XI called "TO DETERMINE COURSE, SPEED, AND RELATIVE POSITION OF A TARGET BY BEARINGS ALONE".

(https://ia800203.us.archive.org/22/i...oard00unit.pdf)

http://www.subsim.com/radioroom/pict...ictureid=10293
http://www.subsim.com/radioroom/pict...ictureid=10294

And also the same method located in 2001 Maneuvering Board Manual, Chapter 6, example 25. (https://www.sliderulemuseum.com/Manu...oardManual.pdf)

http://www.subsim.com/radioroom/pict...ictureid=10295
http://www.subsim.com/radioroom/pict...ictureid=10296

Thinking of giving it a try? :Kaleun_Thumbs_Up:

Great find! Perfect compliment to my existing Mobo thread on here too.

Thanks for the links - more to read now!