Having 100% sonar dispersion would be cheating. But I agree that 20% wasn't much in SH3
. Anyway, it's not like you become invisible to sonar. At close range they can still pick you up but very imprecise. And since they don't know where you are, they might mistake those small pongs for a very far away sub. Pings sent by one escort can even be received by another escort so imagine their confusion. And as soon as you reduce your profile by turning away from the hunters and put a bit of space, then you become invisible.