This is not intended to be a comprehensive set of submarine rules for CS as it is assumed that a diving submarine is attempting to escape rather than to engage its attackers.
A surfaced submarine may announce its intention to dive when it activates. Diving takes two turns to complete. On the first turn the crew clear the bridge and upper deck guns. The submarine moves as normal but no weapons may be fired.
On turn 2 when activated the submarine is diving below the surface. It may till be fired at and rammed.
On turn 3 when activated the submarine has dived below the surface but may still be rammed by Large or Huge vessels
On turn 4 when activated the boat is fully submerged. The model is replaced with a marker showing the point at which it was no longer visible. The marker remains in place for the next 3 turns during which it is vulnerable to attacks by depth charges
Depth Charge Attack
If an depth-charged equipped vessel or aircraft passes over the submarine marker it may make an ASW attack. Only one such attack from a surface ship or aircraft may be made on a single submarine marker per turn. Only one ship or aircraft may attack a marker in the same turn.
The player controlling the submarine secretly rolls two d6 of different colours (e.g. red and white). The following table shows the score required on the red d6 for the attack to have come close to the submarine:
Add 1 for Veteran crews, subtract 1 for Inexperienced crews.
Add 1 if the ship or boat has sonar
Advanced ASW Weapons
Ships with advanced ASW weapons such as Squid, Hedgehog or Mousetrap do not need to pass over the marker. Instead they may attack if the marker is within the forward 60 degree arc of the ship (i.e. within 30 degrees of dead ahead) and within 20cm. This is because they were ahead throwing weapons.
If the attack has come close use the score on the white d6 on the Depth Charge table for the effect of the blast (which may be no damage). Use the "Normal ASW" column for standard depth charges. Use the "Advanced ASW" Column for Hedgehog, Squid Mousetrap and acoustic homing torpedoes
Players are encouraged to add to the 'fog of war' by depositing suitable wreckage around the sub marker. Only the player controlling the submarine and the sub commander knows whether this is real wreckage, or only 'junk' dumped by the submarine.
Note that Hedgehog and Mousetrap were contact weapons. The firer is informed if the target has been damaged by these weapons, but not the extent of damage.
Destroyers using stern depth charge racks can make an attack each turn. Ships using only side depth charge launchers take 1 turn to reload. Advanced ASW weapons take 3 turns to reload.
Damage Whilst Submerged
If the submarine suffers damage that forces it to surface it does so at the end of the turn, regardless of the number of turns that have passed since it began to dive. If a marker is in use it is replaced by the model. The location of the model relative to the marker should be determined randomly - use a wind die, spinner or other random method to determine the direction from the marker, roll 2d6 for the distance from the marker in centimetres.
Limitations on Submarine Offensive Actions
Submarines on the surface can fire torpedoes and deck guns as normal. No weapons may be fired once the intention to dive has been announced. If a submarine is forced to the surface it may not fire weapons until the turn after it has surfaced.
Which ships are armed with what?
All corvettes, frigates, sloops and destroyers in the rules are assumed to be armed with stern and side depth charges. Some US SC-497 Submarine Chaser may only have side depth charge launchers.
The following classes may carry Advanced ASW weapons
• Captain Class (Hedgehog)
• Buckley Class (Hedgehog)