ghost_man8, This is one of those "different units" that the Game Editor does not have settings that would allow us to use it exactly as we would really like so we have to improvise and use the settings available in a way where we can at least be able to use it in the game.
This unit would actually work best if it could either be Air Dropped or transported to an area desired and have the Immobile setting so it could not move......but the Editor will NOT allow either due to the fact that it is used in the Water. (ships cannot be transported or Air Dropped and the editor just does not have the settings needed)...this is another area of the Editor I hope Firaxis will address so we have the ability to use units such as Naval Mines better.
It must be used as a Naval Power (like a Ship) to be able to place it in the water and move where wanted. While this may appear somewhat funny, it is the ONLY way it can work in the Game...and yes, this means that the Naval Mine can go after ships and Attack. IF you want it to be Immobile, just give it Zone of Control, move it where you want it, Fortify it and resist moving it again. What ever strengths you give it, a good defense and high Hit Point will allow it to survive longer. Each Naval Mine represents Many Naval Mines on each square so surviving a ship also represents the remaining Naval Mines on the Square...hope that makes sense.
My settings are EXTREME due to my personal MOD but you can adjust all to fit the needs or desires of your Game. ALL of my units are Extreme so don't let the following settings of mine "Blow your Mind"
Class-Sea
Prerequisite-Magnetism
Unit Statistics:
Cost-(10) =100 shields
Moves-8
Attack-17
Defense-15
Hit Points-6
Zone of Control
Unit Abilities:
Blitz
Radar
Invisible
Detect Invisible
Required Resource- Iron and Saltpeter
Standard Orders-ALL Checked
Special Actions-Airlift
AI Strategies-Naval Power
Personally, I do not give this unit to the AI in my MOD but the AI has other units to compensate. IF you do give this unit to the AI, plan on seeing Naval Mines moving around like ships and going after your Water Units.
All factors considered, the Naval Mine is Fun to use and worth adding...just adjust settings as fits your Game.
Hope this Helps.