Anyway until I learn how to tweak files I have to deal with this passion of mine. Let me explain. I set up some scenarios with Seawolf and 688i and found they are similar in accoustic ability. Pitifully! I set it up to intercept and track a Rubis SSN. Simple stuff. Both boats could not detect over 5000 yards with Rubis doing 7 knts. Shameful. For the heck of it, I play the same scenario with a Sierra class boat and the boat picks up the Rubis at 30k yards and even classifies it correctly. The accoustic abilities of these boats need work. there is too great a discrepency here.