This technology allows subs to defend at 3.
| Version | Attack | Defense | Move | Cost | Special Ability |
| NGE | 0 | 3 | 2 | 8 | Does not participate in normal naval combat. If surface ships start, pass through or end in area with the subs, the defending subs fire at 2, then surviving surface ships (& carrier-borne aircraft) fire back using their attack strengths. There is only 1 round of combat. Subs do not stop movement or attack each other. |