A really cool setup
 

Run 2 separate versions of DW on 2 different comps...link them in multi-player and assign one version for inner works of sub(sonar radio weapons etc) the other is ship control and TMA as well as tactical screen. on the same computer (comp 2)run coldwaters in quick mission and place a neutral target on map. Using WIN-1 keys and WIN-2 (task bar icons will switch inorder on the task bar from left to right)...switch between the two ,so you can toggle between DW and CW on comp 2(I do this via voice BTW using voice attack). Now you got multiple screens with really nice external views of sub to orientate yourself and great underwater ambiance of CW. To top it all off I use voice attack to run comp 2 and can match speed direction and even torpedo launches with my voice and run ship control in DW with the built in voice control.

Its a bit of work to set up but well worth it.Make good use of old retired computers and monitors.