Thermo cline A top-down game of submarine hunting. You never see the enemy on the plot. You hear it: a bearing, a sound, an echo. Turn those into a position before they do the same to you.
SE = SL − TL − NL + DI − DT
signal excess = radiated noise − transmission loss − background noise + array gain − detection threshold
Positive means you hear them. Every knot of speed, every foot of depth, and the weather move these numbers.
1 · Scenario
Hunt Find and sink every enemy boat. Convoy escort Three merchants sail east for 60 minutes. The attackers need to sink two of them. Scouting duel Frigates against frigates, weapons tight. First to hold a fix on the other for two minutes wins. Surface action Weapons free: missiles and guns, ship against ship. Sink or cripple the enemy.
2 · Location
Norwegian Sea Deep water, 1,800 fathoms. A thermal layer splits the ocean. Convergence zones around 33 kyd. Barents Shelf Shallow, 70 fathoms. No layer to hide under. Active sonar drowns in bottom reverberation.
3 · Weather
Calm · SS 1 Quiet sea, long detection ranges for both sides. Moderate · SS 4 More surface noise, deeper layer, radar clutter. Gale · SS 7 Loud sea masks submarines. Helicopters grounded. Ships limited to 20 kt.
4 · Matchup
Sub vs Frigate You command Los Angeles-class submarines against Krivak frigates and their Helix helicopters. Sub vs Sub Your submarines against Victor III boats. No ships, just two hunters listening below the layer. Frigate vs Sub You command NATO frigates and their helicopters against Victor III submarines.
Attack the convoy Sink two of the three merchants. Defend the convoy Keep the merchants alive for 60 minutes.
5 · Forces
Your submarines you command all of them
− 1 +
Enemy frigates controlled by the computer
− 1 +
Take command