Thanks for all the help guys, I reinstalled SH4, patched to 1.4 and installed the mods in a different order this time. I was able to use the 450ft depth meter in the Balao to get to that depth, but she won't go deeper unless I have only TMaru installed. And I can see the 600 ft depth meter while looking around the room in game, but I can't assign that depth to the ship.
At any rate, it's working pretty much for now, I'm able to complete the TMaru crush depth sea trial mission at least
Here's a list of my mods and the order they are installed:
warships_retextured_v1_3
ROW Sound Effects vs_8
ROW Hi Res Sea Foam
1_TMaru_Trigger_Maru_ 1.7.6
3_TMaru_GFX-ROW_Version_5
Addon for Reflections On The Water
maxoptics over TM1.7
RSRDC_P2_TM_v221
NSM4 Classic