What you probably want to do is increase the Nrd level of the SeaWolf sensors (meaning the Seawolf spherical, hull, and towed arrays). This number is on the "Sensor Dialog" menu of DWEdit. The more negative the number, the more sensitive the sensor.
Alternatively you can also modify the frequency ranges of the sensors because lower frequencies are heard further away, but this can be too much of a jump in sensor performance and you probably want to stick with the Nrd ratings first. You can also modify the "max sensor speed" to allow your sensors to work at higher speeds if desired.
To see which sensors apply to the Seawolf platform look in the Object Dialog and then the sensors listed in the lower left hand box.
And just FYI. Questions like these are usually relagated to the
"DW Mod Workshop" section of the forum made to answer these types of questions.