The first mission (for the '39 start date) is always the same. Only the patrol grid can vary. Following missions are random within the limitations of available mission types (patrol, bring spy to location xyz etc.), but there are also campaign missions which are only random considering the patrol grid. Other campaigns are a fixed set of non-random missions e.g. deploying weather stations.

The mission changes like the recon in Rotterdam are random to the degree that they only pull from a limited list of new tasks which include recon of AA capacity or just a change of the patrol grid. Some more exotic stuff like meeting with japanese subs will appear later in the war.

Later war missions and campaigns also include objectives from Labrador to Sierra Leone with some newmission objectives even.

Overall it still can get a bit repetitive after a while. Changes with new subs from the type VIIB onwards are small and the gameplay won't offer new experiences once you know how to deal with hedgehogs and rocket rails on airplanes.

The answer above is not clear about wether patrol missions are random or not, it's been awhile that I've been playing this game but I still don't know.

To clarify: Patrol missions have random factors if:
At a certain date and time you make an encounter on a certain place in the map, and in a next career at the same time and location you DON'T make this encounter, meaning the enemy routes are not preset. That would be a proof of randomness and a factor of real dynamism.
It's still unclear to me if that happens or not. In the negative, I'd rather don't want to know because it would highly break immersion. Afterall sub captains could never know about an encounter even by radio message, there are too many variables to make the encounter actually happen or not happen - and a scripted approach would be a wrong setup for a sub game. I hope it's not true for the patrol zones.

Instead, All side missions like 'get info on the port xxx' etc. are of course scripted and not random except for the encounters you could make before reaching the mission target. Once on the target, the setup is always the same, if I judge about how the Scapa Flow mission is made - which I have done 2 times starting from the port because of a bug. It's possible however that at different difficulty levels the setup will be different, but then it would be the same at every such level although different from level to level.
Here again, I don't know exactly, in order to know I will have to play different careers at different difficulty levels in the same time interval.

Originally posted by Gelete Rojo:

An example: in my first mission I was ordered to patrol a certain area of the Northern Sea and then to take some intel information on the port of Rotterdam, in The Netherlands. Now I am in my second mission and I have been assigned with another patrol tasks. My question is, If I start another capaign again, in the same year and in the same port, will it also has the same first mission or will I receive completely different orders from the Bdu?

There are historical events that will interact with the map and your gameplay in predictable scripted ways.. but besides that most missions are somewhat "random".
Historical events like the invasion of France.

The mission pool is essentially the collection of all possible missions available to your current location and operational range.
This pool is then randomized, and you are offered the top three missions (or however many you selected during campaign setup).
Spending points can modify this selection, allowing you to unlock more choices.

The composition of the mission pool depends on several factors:

The mini-campaigns you have unlocked ( Happy Times, Scappa Flow, and Enigma) influence the pool.
Specific missions related to these campaigns will likely be present, alongside generic missions like standard patrols.

Once the pool is formed, the missions are scrambled, and a subset is presented to you.

This system creates a mix of scripted and random elements.
Missions tied to mini-campaigns are predictable in their general theme, but the specific missions or locations often remain uncertain, unless the mission is heavily scripted, as is the case with Scappa Flow.

Adding to this are the dynamic shipping movements and convoys across the map, which further influence the gameplay.

While you can expect missions tied to unlocked campaigns, predicting exactly which missions will appear is unlikely, except in the case of fixed, scripted events.

Thanks all pals, you are very kind!

All is clear now.

It is very important for me the fact that the convoys and shipping movement in the map is done in a random fashion, that's a must in my book. I was afraid that certain encounters with the ships will always happen in the same grid coordinates.

Originally posted by Mouse Rat:

Originally posted by Gelete Rojo:

An example: in my first mission I was ordered to patrol a certain area of the Northern Sea and then to take some intel information on the port of Rotterdam, in The Netherlands. Now I am in my second mission and I have been assigned with another patrol tasks. My question is, If I start another capaign again, in the same year and in the same port, will it also has the same first mission or will I receive completely different orders from the Bdu?

There are historical events that will interact with the map and your gameplay in predictable scripted ways.. but besides that most missions are somewhat "random".
Historical events like the invasion of France.

The mission pool is essentially the collection of all possible missions available to your current location and operational range.
This pool is then randomized, and you are offered the top three missions (or however many you selected during campaign setup).
Spending points can modify this selection, allowing you to unlock more choices.

The composition of the mission pool depends on several factors:

The mini-campaigns you have unlocked ( Happy Times, Scappa Flow, and Enigma) influence the pool.
Specific missions related to these campaigns will likely be present, alongside generic missions like standard patrols.

Once the pool is formed, the missions are scrambled, and a subset is presented to you.

This system creates a mix of scripted and random elements.
Missions tied to mini-campaigns are predictable in their general theme, but the specific missions or locations often remain uncertain, unless the mission is heavily scripted, as is the case with Scappa Flow.

Adding to this are the dynamic shipping movements and convoys across the map, which further influence the gameplay.

While you can expect missions tied to unlocked campaigns, predicting exactly which missions will appear is unlikely, except in the case of fixed, scripted events.

All you say here long and large is that side-scripted missions are not random which is self-explaining otherwise they could not be played out.
But are patrol missions that you need to do in a certain map zone random or not as for the encounters you make?
In the SH series, a spawn circle is defined with a chance of a ship group spawning in some random place in the circle at some random time within a small time intervall, so you are not sure to ever encounter these units (their composition is also slightly random). And there are other fixed convoys that fit historical convoys or ships (e.g. the Bismarck route at the right time). This makes it dynamic but not random. I wonder wether it's the same in this game.

Originally posted by japp_02:

All you say here long and large is that side-scripted missions are not random which is self-explaining otherwise they could not be played out.
But are patrol missions that you need to do in a certain map zone random or not as for the encounters you make?
In the SH series, a spawn circle is defined with a chance of a ship group spawning in some random place in the circle at some random time within a small time intervall, so you are not sure to ever encounter these units (their composition is also slightly random). And there are other fixed convoys that fit historical convoys or ships (e.g. the Bismarck route at the right time). This makes it dynamic but not random. I wonder wether it's the same in this game.

I'm not a developer for this game, so my thoughts are extrapolations and educated guesses based on what I’ve observed.
That said, I think my interpretation aligns with how the mission pool operates.

Now, about the distinction between a dynamic campaign and a random one:

The mini-campaigns available (e.g., "The Black Pit," "Happy Days," "Norwegian Campaign," "Gibraltar," etc.) are fixed.
There’s nothing random or dynamic about the campaigns themselves.
You get fixed predetermined intervals you get rewards from.

The missions within these campaigns, however, seem to follow a dynamic structure within a defined framework.
For instance, while you can’t predict the exact location and timing of a convoy, the general type of mission and its events are consistent.

For example:

During the Norwegian campaign, you can reliably expect escort missions or patrols within specific sectors around Norway.
In Scapa Flow, you know where to find battleship.
In the Enigma, there will always be one destroyer and one corvette stationed above the wreck.

As for how enemies spawn or how convoy routes are generated,i don’t have a solid intuition.
However, it seems logical that certain mission types (e.g., port-to-port convoys) are predefined to an extent, with random elements like the specific ships attached to those convoys.

I’ve also noticed that ships sometimes change course when you approach them.
I’m unsure if that’s an event triggered by proximity or simply part of their pre-determined but randomized course from the moment they spawn.

So there are a few answers that are unclear, like how are the general shipping determined around your sub .. since seems to be a proximity thing, but the range can be relatively large.

Thanks for your insights, Mouse Rat.