I am curious how you came to your claim. What tools/calculations did you use/make to provide a better distance?

Well, The conclusion is that the WO is quite right with his binoculars. As a matter of fact, he's better than the persicope @ 10x and a advanced calculators trigonometry. The periscopes ticks are obviously very wrong. At 10x the ticks are 0.1578 - 0.1580 degrees... not 0.1 which would be the logical in this case.

I honestly don't know if they where that lousy on optics at WW2, but I doubt it. It has been around for a while, you know. I guess if you're out for realism, the WO is closest to it. The attack periscope is - for real - useless...

Well, I thought the periscope and trigonometry was right to begin with, but it was not - my bad. I calculated it in a live game and career so I didn't have the time to get down on it. I made a rough estimate to consolidate the periscope and WO and came to the conclusion that the WO was ~200m off.

In the results above, I've been using a estimated FOV (~60), a for the purpose made mission and - a whole lot of torpedoes at different speed and their average time to impact, to measure the true distance. (This since I don't trust neither the scope or the WO). I'll dig deeper into this later, since I can't find all answers here. But for now it will do...

EDIT: The WOs estimates seems to be floored and not rounded. May have been mentioned around here but anyways...

Those marks in the stock periscope are not to be trusted anyway. In stock they seem to be for decoration only. Their rendering seems to be hardcoded in the game, to much discontent of modders trying to use a different image. They can't get rid of it , only enlarge enough making it go out of view. And then overlay their own image. So in the end what you measure also depends on what version/mod of the game you use. If they changed the optic values.

Also, there is no reason why a mark should mean 1 degree or 0.1 degrees. What is important is that those marks signifiy some ratio between size or height and distance. If it has the right ratio you can 'easily' convert appearant-size to distance (if you take it's physical-size into account)

Imho, the WO is actually way too precise. No way he could tell 11km apart from 11.1km in real life with just his eyes

All I'm saying is that the periscope is not to be trusted. It's all wrong... GWX for sure... that's all I'm playing.

I disagree... You don't have to use height, (which is awful if you get in to rough wathers). You're usally better off, using lenght of the target and estimated AOB. It's good enough for me though.

Imho the WO is more realistic than the error of optics in SH3 and GWX, despite his accuracy. (Optics from 1700 would have done it better.) I might be wrong though...