Advanced, Optional Rules for Submarine Warfare

Placement

1) During the gather forces/ fleet construction phase, assign 2 “decoy” markers to each submarine you control. Markers must be generic on the “face up” side, and unique on the “face down” side. Aside, designate which is the actual Submarine and which is the decoy.


2) During the fleet deployment step, place both markers as normal on the game map (i.e. up to the middle of the map, beyond the center line if the sub has infiltration, U-459 deployment SA, etc.)



Sea Movement

3) During the Sea Movement phase, move both markers representing the sub in a regular/legal manner (i.e. move one space per turn, no more than one sub per square, etc.) Markers assigned to a specific sub are not required to operate near each other.


Note: this presumes the decoy markers are clearly marked AND detailed in the controlling players notes. Yes, this is going to require some small amount of paperwork of the players,


The Hunt

4) Enemy aircraft and Surface units use a variant of the search rules for long distance battles (pg. 48, core rule book) to locate enemy Submarines. A single unit within the square (air or surface) makes a search attempt at the end of the Air Placement phase, but before the Air Defense Phase. The unit with the best chance of success makes the roll. The difficulties are as follows:

Patrol Bombers: 4+


All other air craft w/ ASW ability (i.e. a depth charge symbol in the Attack type Colum on the Unit card): 5+


Surface units w/ the ASW ability (i.e. destroyers, MTB’s, etc.): 5+


Night conditions and/or smoke/weather conditions add a difficulty modifier of -1 (A patrol bomber searching for a sub at night, difficulty raised to 5+).


Each enemy unit in the square, air or surface (except the submarine being hunted), inflict a -1 difficulty modifier to the search attempt (it’s hard to hunt subs while your being strafed/shelled/torpedoed).

In contrast, each additional, ASW capable friendly unit in the square ADDS a +1 to the result (i.e. 2 destroyers searching a square would need a 4+, a patrol bomber and a destroyer search on a 3+).


Any units that have the Special Ability “Sub Hunt” gain an additional +1 (i.e. 2 destroyers, 1 w/ the “sub hunt” SA need a 3+ to locate a sub. 2 destroyers, 1 w/ “sub hunt’ and a patrol bomber would locate the sub on a 2+).

Some subs have the SA “Elusive Quarry” (units with this SA cannot have the SA “Sub-Hunt” used against them). This SA applies to all the markers assigned to the sub in question. Additionally, an additional -1 modifier is applied to the searching units


Finally, no matter how many units or bonuses you are able to fit into a square, a search result of “1” always fails. (so, 4 “Javelins” & 4 PBY’s can still miss finding the U-552 on a search check result of “1”).


Example: During the Sea movement phase, HMS Javelin and USS Fletcher move into a square the controlling player believes a U-552 is lurking. During the Air mission phase, that player adds a PBY Catalina to the square. After the last aircraft are placed for the phase, the Allied player makes a search attempt with his unit that has the best chance of success (the PBY at 4+). He adds the cumulative bonuses of the other, friendly units in the square (+1 for each Destroyer and +1 for the “sub-hunt” SA on HMS Javelin). However, the best result the allied player can get is a 2+, as a “1” is always a failed attempt. If the square also contained a Z-20 destroyer and a Bf-110, the difficulty would be modified to 4+.


Submarines search for other subs on a 5+. Additionally, they do not gain/suffer any of the above-mentioned modifiers.


Upon a successful search check, the attacking player may engage the “submarine” during the Air, Surface and Sub attack phases, respectively.


Air units that fail to locate a submarine are free to attack other enemy units located in the square. (i.e. a Sunderland flying boat was leading the hunt for a U-510. Within the same square was a Z-20 type destroyer. The Sunderland fails the sub-search check and therefore cannot engage the sub. However, it is now free to attack the Z-20 instead).



The Attack

5) During the Air attack phase, the hunting player makes all ASW attacks as per the standard game rules. If the attack is successful, the counter is revealed to be either a (now damaged/destroyed) submarine, or a decoy. A revealed, surviving sub is placed on the map with all applicable markers (i.e. damage/ crippled, suppressed, etc.). A decoy marker is removed from play.


6) If the attack is un-successful, the decoy counter remains in play, but may be attacked during the….


7) Surface Attack Phase. Surface units with the ASW ability may engage the marker/revealed submarine as normal (all applicable bonuses and effects). As during the Air Attack Phase, a successful attack upon a marker reveals a damaged/destroyed submarine or ‘decoy”.



8) Markers revealed to be decoys are removed from play.



Submarine Attacks

9) During the Submarine attack phase, one of two possibilities exist:

a) A revealed submarine attacks in the usual manner with all applicable bonuses and minuses, or…


b) A concealed Submarine attacks. When attacking with a concealed submarine, the owning player follows all the standard rules for submarine attack (i.e. declare the target, sound off any bonuses and minuses for the attack, roll the dice).


c) If the target of the attack is in the same square as the attacking submarine, the sub is revealed.


d) Optional: any time a sub attacks any surface unit, the attacking sub is revealed. (I personally like the version above, but this will likely make the mechanic simpler to use).


e) At NIGHT ONLY: During the Submarine attack phase if the target has been hit previously during any phase a successful Submarine torpedo attack hits on a roll of 5 and 6.


Re-concealment

10) A revealed submarine has the potential ability to disappear from the enemy’s view. This can be done in a few different ways:

a) During the sea Movement Phase, if a Submarine manages to move into a square containing a storm/smoke/fog counter, it is replaced on the board with a decoy counter.


b) After the Sea Movement and Air Placement phases, if no enemy units are placed in the square with the submarine in question, the sub is replaced with a decoy counter.


c) If a submarine is able to re-conceal its self (i.e. allowed to get away), place two markers in its place. (This should recreate the difficulty of locating the actual sub). Denote the markers accordingly on your fleet roster.


11) Revealed submarines that do not move during the Sea Movement phase remain revealed, with the exception being if a squall/fog marker enters the square by random placement, the sub in question becomes concealed and is replaced by a marker.


Note: Certain SA’s are designed to assist and support submarines (i.e. pinpoint, vector sub.), These abilities remain unchanged, however, an ability that is used on a concealed marker/decoy can only be used on a single marker. Example: A BV float plane uses its “Vector Sub” SA during the appropriate phase. The controlling player may move a single marker, not both.



Mines

12) Submarines are subject to the effects of Sea Mines (When a sub enters a square containing a mine field, the controlling player rolls a die. On a “1” the sub suffers 1 point of hull damage, on a “2” it suffers 2 points of hull damage).


13) Mines can be designated as either secured or drifting. Drifting mines use either a scatter template or the D6 method used to move clouds/ rain squalls. Drifting mines scatter during the end of turn phase.


Note: This subject has been debated within our group for some time. Here’s a chance to see how it’ll actually work.

An additional suggestion was made, allowing players to “purchase” additional decoy markers for their subs. I like this idea in principle (i.e. each additional token costs 5pts), but it should be limited to 1-2 extra tokens (keeping players from purchasing 2 subs and 30 tokens with their 100pts).