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A study of stereoscopic rangefinders
Posted: Sat Jan 17, 2026 8:05 pm
by Craiglxviii
To answer a question on Quora (how tiring were BISMARCK's rangefinders to use?) I found the following.
Page 69 for reference, the data is fascinating.
https://apps.dtic.mil/sti/tr/pdf/AD0200796.pdf
Re: A study of stereoscopic rangefinders
Posted: Sat Jan 17, 2026 8:16 pm
by Nik_SpeakerToCats
Been a while, but I read some-where that 'Dazzle' camo scheme was surprisingly effective against one of the two main types of optical range-finder...
But the Germans preferred the other !!
Re: A study of stereoscopic rangefinders
Posted: Sat Jan 17, 2026 8:29 pm
by Craiglxviii
Nik_SpeakerToCats wrote: ↑Sat Jan 17, 2026 8:16 pm
Been a while, but I read some-where that 'Dazzle' camo scheme was surprisingly effective against one of the two main types of optical range-finder...
But the Germans preferred the other !!
Correct- razzle dazzle worked against coincidence rangefinders but not stereoscopic.
Re: A study of stereoscopic rangefinders
Posted: Sun Jan 18, 2026 9:15 am
by Nik_SpeakerToCats
A thought: Given periscope constraints, wouldn't U-Boot range-finders be 'coincident' ??
( And, yes, need for multiple wide, wider, widest stereo optics for light, medium, heavy weapons' fire-control that spawned infamous 'FUUSOOO !!' masts. How else, in that era, could you reliably track, tackle multiple targets ?? )
Re: A study of stereoscopic rangefinders
Posted: Mon Jan 19, 2026 12:51 pm
by Craiglxviii
Nik_SpeakerToCats wrote: ↑Sun Jan 18, 2026 9:15 am
A thought: Given periscope constraints, wouldn't U-Boot range-finders be 'coincident' ??
( And, yes, need for multiple wide, wider, widest stereo optics for light, medium, heavy weapons' fire-control that spawned infamous 'FUUSOOO !!' masts. How else, in that era, could you reliably track, tackle multiple targets ?? )
They used stadimetric rangefinders.
Re: A study of stereoscopic rangefinders
Posted: Mon Jan 19, 2026 2:02 pm
by Nik_SpeakerToCats
Ah...
Hasty google-search required, as that's a new term to me !!
A very few ranging shots would establish beyond doubt if target is the size of initial estimate, hence distance.
eg destroyer vs destroyer leader vs light cruiser etc...
Then it gets bloody...
Re: A study of stereoscopic rangefinders
Posted: Sat Feb 07, 2026 12:20 am
by RJGFox
I’ve been looking for, but never found, an image of what the view through a big gun battleship’s rangefinder would look like…
Re: A study of stereoscopic rangefinders
Posted: Tue Feb 10, 2026 7:33 pm
by M.Becker
Nik_SpeakerToCats wrote: ↑Sun Jan 18, 2026 9:15 am
A thought: Given periscope constraints, wouldn't U-Boot range-finders be 'coincident' ??
Subs used rangefinders when submerged? I thought they used lines like in a hunting scope.
The target is ID-ed as X, making it Y long, meaning Z length/height in lines translates to range A.
Re: A study of stereoscopic rangefinders
Posted: Wed Feb 11, 2026 8:29 am
by Craiglxviii
M.Becker wrote: ↑Tue Feb 10, 2026 7:33 pm
Nik_SpeakerToCats wrote: ↑Sun Jan 18, 2026 9:15 am
A thought: Given periscope constraints, wouldn't U-Boot range-finders be 'coincident' ??
Subs used rangefinders when submerged? I thought they used lines like in a hunting scope.
The target is ID-ed as X, making it Y long, meaning Z length/height in lines translates to range A.
They did (yes to both). The rangefinder in a periscope is both the gradiation lines, and also a prism tha brought the target down to the waterline by turning a hand wheel on the periscope itself, which supplied angular data.
Re: A study of stereoscopic rangefinders
Posted: Wed Feb 11, 2026 8:30 am
by Craiglxviii
RJGFox wrote: ↑Sat Feb 07, 2026 12:20 am
I’ve been looking for, but never found, an image of what the view through a big gun battleship’s rangefinder would look like…
Haven’t been able to find tha, but if you have ten minutes this video is fascinating. I could watch it all day.
https://youtu.be/gwf5mAlI7Ug?si=gBXYuwIU-BjiHT0b
Re: A study of stereoscopic rangefinders
Posted: Wed Feb 11, 2026 5:54 pm
by Sukhoiman
yup, then it all becomes a matter of connecting up these in series or parallel depending on the differential equation. Some can get quite large (narrator lists 25 inputs).
Electronics, micro circuitry and software makes this all so much easier since.......but it sure is pretty as hell seeing their analog grandaddies heh.
Re: A study of stereoscopic rangefinders
Posted: Wed Feb 11, 2026 7:06 pm
by Craiglxviii
Sukhoiman wrote: ↑Wed Feb 11, 2026 5:54 pm
yup, then it all becomes a matter of connecting up these in series or parallel depending on the differential equation. Some can get quite large (narrator lists 25 inputs).
Electronics, micro circuitry and software makes this all so much easier since.......but it sure is pretty as hell seeing their analog grandaddies heh.
The computer was mentioned as 30,000lb weight…