There is a way to get a highly refined and accurate representation of a plotting crew working for you without getting too much information: Trigger Maru. Here is why.
In the stock game, your attack map shows a ship silhouette. This tells you exactly what kind of target you have identified. Its color shows you whether it is friendly, neutral or foe. It has a velocity vector tail to show its exact course. And in text beside the silhouette is the ID, course and speed. That's WAY too much information for a radar sighting or a visual sighting on the horizon.
Trigger Maru kills the text. You don't see the ID, that the ship is going NNE at slow speed. Then all contacts are gray. You surely don't know if a target is friend/foe/neutral unless you have identified them first. You cannot because the silhouettes are also nerfed, replaced by a black position dot on your nav map.
So if your radar shows a contact, that's ALL it shows. You must mark its position with an "x" and mark it again at a later time to establish course and speed, just like the real submarines had to do.
Detecting zigs is just as difficult, in this case more difficult than in reality, because a crewman would be assigned full time to track the predicted bearing of a target and when the predicted bearing and actual bearing differed, he would call "zig toward" or "zig away." We're going to be handicapped in that regard because you are a one-man plotting crew here.
See all my instructional videos for illustrations of TMO plotting in use. It is highly evolved and gives the most realistic portrayal of what you in position of captain would be doing on the submarine, without giving you too much information.
Dramatization: Captain is on the bridge when the contact is discovered.
Exec: Cap, we have a target, bearing 249, range 5.5 miles.
Captain: OK, I'm coming down to the control room plotting table to plot it. Dufus, you have the helm for five minutes.
Uh.... every time the contact is updated the captain is going down the ladder, wrecking his night vision to plot the thing himself and analyze the plot? I think he's going to skipper the Admiral's garbage scow when he gets back to Lockwood's office! That's insanely stupid.
There is the argument that the TM plotting system is unrealistic because it plots the exact physical position of a visual sighting. That's hardwired and unavoidable. If you have radar, it is not unrealistic. Radar was the gold standard of position determination: much better than stadimeter. It did give you a precise position. Skippers assumed that their hits would be reduced by at least 50% if they were deprived of their radar. They were right.
So we are left with accepting one easily ignored (just don't use visual sightings' positions as reported in TM with map updates on) problem, vs LOTS of problems, especially attack map useless, with map updates off that make it a ludicrous way to play. Personally, any method that eliminates the ability to check TDC data against the plot on the attack map gets the fail buzzer from me.
Playing with map updates off is like driving with a bag over your head. Challenging, yes! Interesting, yes! Realistic, no!
Here is a screenie of a Dick O'Kane attack with the TM plotting system. See the already identified and tracked target there. From the plot none of that is obvious. It is a radar position. What is unrealistic there? NOTHING! As he advances toward my position, I will continually refine his course and speed until I am satisfied or he is too close for comfort. At that point I will submerge and his position will be fixed by the intersection of established target track and his bearing. That is also totally realistic. When he reaches the shoot bearing, he will be sunk.
