[yamato9]

Here is my setup, just for comparison:

Alfa

AccelerationRate=0.35
DecelerationRate=0.045
RudderTurnRate=0.25
TurnRate=1.5
PivotPointTurning=0.256
DiveRate=0.17
SurfaceRate=0.17
BallastRate=0.25

I get with this about 40sec to turn 180 degrees on full speed, which is stated on wikipedia about Alfa.

Skipjack

SurfaceSpeed=15
SubmergedSpeed=30
AccelerationRate=0.3
DecelerationRate=0.05
RudderTurnRate=0.25
TurnRate=1.4
PivotPointTurning=0.256
DiveRate=0.15
SurfaceRate=0.15
BallastRate=0.25

LA

AccelerationRate=0.27
DecelerationRate=0.04
RudderTurnRate=0.25
TurnRate=1.2
PivotPointTurning=0.256
DiveRate=0.15
SurfaceRate=0.15
BallastRate=0.25


Usually vessels with high length to beam ratio have greater turning radius but also they are more directionally stable, meaning that the course is easier to control. While vessels with low length to beam ratio are directionally unstable so they have smaller turning radius but in same time it is harder to control their heading with rudder. This is situation when you are on North course 0deg and you apply 30deg right rudder to make hard turn toward 180deg South. When you reach 180deg South, you set rudder midships but your ship continues to turn and it overshots wished course for more than 60deg. And now you are effectively on 240deg South-west course. For instance container ships are more directionally stable ships than tankers. But tankers have a tendency to turn in smaller radius.

Same probably applies to submarines and if you look carefully, russian submarines (and skipjack) have much lower length to beam ratio than L.A 688. So general guideline in determining which submarine have better turn rate is length / beam ratio and rudder size.