#1 thing to remember when adding new MOD's.
- Make sure you are in port when activating MOD's.
- Enabling MODs while at Sea may cause unusaul behaviour
Not saying this is what happened, just something to keep in mind.
I think it was Stormfly or Anvart that did the math and pointed out that the Observation Periscope is suppose to be usable in calm sea at depth of approximately 15 meters. This is like extending the Obs Periscope 2.5 meters more then most available MODs.
You may want to add
[WIP] FX Update by TheDarkWraith as last MOD.
The settings for ObsScope Extend height are located in this file
data\Objects\Sensors\UBoot_Sensors.sim