The lack of "hearing" a ship by the player using passive sonar (hydrophone), yet your Sonarman usually
can, is a stock game bug. It's enhanced even more by modding ships to do authentic behavior as both TMO and RSRDC try to do.
If you compare the stock game campaign files to either TMO's or RSRDC you'll find why the modded game preforms worse than its stock counterpart.
As propbeanie points out, the game makes a distinction between what a ships MaxSpeed= figure is (found in its .sim file), compared to its Speed= figure found in its traveling speed between waypoints of the Campaign files. If the ship is set to travel less than half its Maxspeed= figure....you'll not hear it.
In most, if not all stock game campaign ship waypoints, the convoy ships travel at 9 knots or more. Most freighters have a MaxSpeed of less than 18 knots. So, a 9 knot travel speed is either equal to, or greater than, half of an 18 knot MaxSpeed....you'll hear it just fine. Their assigned escorts to those convoys will follow the same speed as the ships their protecting, so the game seems to ignore this speed rule for the escorts when their assigned to slower freighters.
In TMO or RSRDC the Campaign ships travel at all sorts of speeds between waypoints. When they travel less than half their MaxSpeed figure.....you're as deaf as a post to hearing them with passive sonar. That's why this "bug" becomes more prominent with a modded game. It's like the developers knew this shortcoming, and just made sure you didn't notice it by keeping the freighters traveling above half their MaxSpeed figure.
I have a plan to correct this behavioral bug, without increasing the ships traveling speed, but its no small task. Campaign files and ship .sim files will need to work in "sync" with each other to eliminate this bug. Fotrs Ultimate having their huge inventory of ships will be the perfect place to correct this behavior of having deaf hydrophone operation. Much like the elimination of hearing the constant "Yes sir", "Yes sir"...... response heard in the stock game, my correction will have little fan fare outside of simply making the equipment work as expected.
