level of complexity
 

tell me how to disable the boat marker on the map ?

Use damp-paper and pencil instead.

have you read the question carefully ?

Your true position matters very little. All that matters in game is your position relative to the convoy, and other u-boats. Once you're in sight of the convoy, when surfaced your position relative to the convoy can be reasonably accurately determined. Once submerged, this becomes harder but you can still plot it via observations from 'scopes and hydrophone. Once deeper than periscope depth, only a log of headings and times can plot your positions, augmented by hydrophone readings.

As the game already operates thus, it's hard to see why disabling the surfaced position indicator would serve any purpose at all.

Hence my quip about "damp-paper".

this answer is much better...
tell and odometer also does not matter when calculating move ?

sorry for the translation ... google

It's true that submerged you can either calculate the vector of your movement to update position from a known point (so many minutes at a known speed of x knots, converted to meters), or, you can reset the odometer at every change of heading and simply plot the reading from it before it is reset to zero.

Welcome aboard!
 

Since nothing else is plotted on the map automatically the plot of your own position gives you little information to use it with. But yeah, once the Scapa Flow mission becomes a thing, positioning in the vicinity of shores and such becomes important. And then being able to disable the position indicator would add a level of difficulty for advanced players.

I would presume, that night or day, the Scapa mission would be submerged anyway, so it's moot is it not?

I believe that players need to be taught real navigation.
GPS tag on the map is for wimps

The navigator-bot does update the position once submerged. So if they are enabled for whatever reason and a human player is not taking that role it probably will loose that level of difficulty. But let's not get ahead of ourselves just yet. Let them develop first.

here is a device for navigation in the air.
there should be no other
https://yandex.ru/turbo?text=https%3...25BD%25D1%2582

There's also a circular-slide-rule used in aviation navigation, commonly called a "whizz" or "prayer" wheel, which is a very powerful tool for speed/time/distance/drift and vector calculations (and a great deal more specific to flying). When I was instructing students on air-navigation I'd start by setting them a problem, and they'd compute it with electronic calculators, and I with the "prayer-wheel" - and they never ever arrived at the solution before I did. Having proved the use of the (batteryless) wheel, I'd then teach them how to use it. Sextant use is no longer taught in aviation, but a form of sextant was used in astro-navigation (position derived from stars) until the 1950's when the ubiquity of radio-aids made astro-navigation redundant.

The accurate use of sextants would be extremely difficult on a U-boat due to the pitching and rolling of the boat, so I would expect it was a method of last-resort for fixing position. DFing known LW radio transmitters would be a much easier method, with sextant use only being of use in calm seas.

why can't I send private messages to you ?

You're right that at least it is realistic when you're submerged. But why would it be a good thing to have unrealistic features (GPS) when surfaced? The thing is that if you have been submerged for a while and then resurface, the game will give you your correct position. In reality you would still have to trust your previous navigation. You cannot just surface to get the answer. This is especially true if you maneuver in panic during an escort attack and loose your navigation. A lot of your previous convoy mapping would be lost because you no longer know your position!