Alan R. Arvold


   The following variant rules are for the game SOPAC. Most

players will recognize them from the Great War At Sea series of

games. I have transcribed these rules to SOPAC and modified them

to take into account the differences of fleet operations in the

Second World War as compared to the First. Also there is a piece

of errata at the end of this article which I missed in my

previous errata article. These rules and errata should be

considered to be unofficial.


16.0 Submarines


16.6 Submarine Aces

Some scenarios direct that a side may have a certain number of

submarines that are captained by skilled and energetic

commanders. The player must designate on the Ship Data sheet

which of his submarines have the ace commanders. Submarines with

ace commanders have a -1 die roll modifier against ASW attacks

made against them. They also have a +1 die roll modifier for

attacks that they make against ships. These modifiers are in

addition to those on the appropriate tables.



19.0 Mine Warfare

Minefields may be placed along Zone boundaries. Some are placed

at the beginning the scenario (see scenario instructions); others

may be sown during the course of play.


19.1 Minefield Location

Note minefields on the Log Sheet (using Log Sheets from the Great

War at Sea series of games) writing down the two zones bordering

the minefield. A player is not required to inform his opponent of

the location.

Example: The Allied player places a minefield west of Savo

Island. On his log sheet under the "Minefields" column he writes



19.2 Entering a Minefield

When an enemy fleet marker crosses a mined sea zone boundary, the

player who placed the mines informs his opponent. The Player who

moved the fleet stops moving it and for each ship in the fleet

rolls two dice and consults the Minefield Table listed below.


Minefield Table

Ship is damaged on a result of 11+.


+1 for each additional minefield (maximum of +5)

+2 for ship moving speed 2 or greater during turn's Naval

   Movement Phase


19.21 Procedure: Resolve each mine hit by rolling one die and

consulting the Mine Damage Table listed below.


Minefield Damage Table

Die Roll         Damage

  1-2            1 Hull

   3             2 Hull

   4             3 Hull, lose one speed level

   5             5 Hull, dead in the water

   6             Ship sinks


19.22 Friendly Fire: Minefields do not effect fleets or flotillas

belonging to the player who placed them.


19.23 Mines in Combat: Ships which crossed a sea zone boundary as

a result of leaving the tactical map (6.46) also must have

possible mine hits resolved.


19.24 Submarine Flotillas: Due to their hidden nature on the

Operation Board, submarines are only effected by mines if they

make an attack against enemy ships in a sea zone which contains a

minefield on one or more of its boundaries. After all sub attacks

in the sea zone have been resolved, the enemy player who owns the

minefields announces that there are mines in the sea zone. The

player with the subs randomly picks on of his surviving subs

which is the recipient of the minefield attack. The enemy player

rolls on the Minefield Table with two dice. An 11 or 12 means

that the submarine hit a mine and is now sunk. There are no

modifers. Any other result means that the sub made it through the

field unscathed. In either case the enemy player must reveal the

location of one minefield in that sea zone to the other player.

(Okay it's abstract but it works.)


19.25 MBT Flotillas: MBTs are not effected by minefields.

(Due to their small size and and very shallow draft, MBTs of this

war usually were able to pass through minefields with no problem.

Only those mines which were on the surface were the only real

threat to the MBTs and most of the time the boats moving through

the field at a slow speed could avoid them. Granted there were

occasional MBTs lost to mines but these were usually due to cases

of stupidity.)


19.26 Aftermath: After the player moving his or her fleet has

resolved possible mine hits for one-fourth of the ships in the

fleet (round any fractions up), he or she may stop moving the

fleet and re-plot its movement for this turn and the following

turns (unless the fleet crossed the boundary when leaving the

tactical map).


19.3 Laying Mines

Ships capable of laying mines are noted in the scenario

instructions. Note that a ship's minelaying capability may not be

the same in every scenario.


19.31 Mission Statement: To place a minefield, a ship must be

part of a fleet with a minelaying or a raid mission and must

remain in the sea zone for four turns. Note "mine" on the log

sheet for those turns. If the ship does not move, fire (including

bombardment and anti-aircraft fire against attacking planes) or

suffer damage during those turns, the player may note one of that

sea zone's six boundaries as containing one minefield. The

minefield does not become active (effect passing enemy ships)

until the next turn.


19.32 Extent: All of a sea zone's boundaries may be mined.


19.33 Extra Mines: Additional minefields may be placed along a

boundary already containing a minefield.


19.34 Prohibitions: Minefields may be placed in any sea zone

within two sea zones of a sea zone that contains land (not an

island). Count the sea zone that the minefield occupies, but not

the sea zone the land occupies to determine the distance. An

island is land that is present in only one sea zone. All other

land is coastal.

Note: Although all of the land on the board are islands in the

geographic sense, in game terms they are classified as coastal.

For the record the only island sea zones on the board are as

follows: K9, K26, K27, L12, M33, N32, O31, P13, and P14. Sea zone

U32 (Espiritu Santo) is considered to be coastal. Note that some

of these islands are within range of other coastal sea zones and

thus can be mined.


19.35 Activation: A player placing a minefield may delay its

activation. Note the game-turn (any turn after that during which

it was placed) on which it becomes active. An inactive minefield

has no effect on enemy ships.


19.36 Infiltration: Minefields may be placed along the boundaries

of a sea zone containing a major base.


19.4 Minelayers in Combat

When a minelayer (or another ship acting as minelayer) is hit by

gunfire, bombs, or torpedoes in combat, the owning player rolls

one die. On a result of 6, the minelayer explodes and sinks.


19.41 Panic: A player may order a minelayer (or another ship

acting as a minelayer) to jettison its mines; its fleet mission

must be changed to abort and it may lay no more minefields in the

current scenario but is not subject to exploding if hit in combat

(except through the usual damage results). A ship may not

jettison mines during combat.


19.42 Definitions: A warship is only considered to be a minelayer

for purposes of this rule if it is on a minelaying mission and

the scenario instructions state that it is capable of laying

mines. Minelayers (type ML) are always subject to this rule.


19.5 Auxiliary Minelayers

Some scenarios direct that merchant ship counters be used to

represent auxiliary minelayers. These may be used as multiple-

ship counters to represent more than one minelayer. Auxiliary

minelayers have all the characteristics of the merchant ship

counter used used to represent them (and may explode in combat).


19.6 Sweeping Mines

A minesweeper may be used to remove minefields. Only minesweepers

and those ships noted in the scenario instructions as capable of

sweeping mines may remove mines.


19.61 Mission Statement: To detect or attempt to remove a

minefield, the minesweeper must be part of a fleet with a Mine

Sweeping mission.


19.62 Detection: Before a minefield may be removed, it must first

be detected (minefields placed by the same side are always

detected; you do not have to detect a minefield to sweep your own

mines). To detect an enemy minefield in a sea zone, the

minesweeper must remain in the sea zone for an entire turn. Note

"detect" on the log sheet for that turn. If the minesweeper does

not move, fire (including bombardment and anti-aircraft fire

against attacking planes), or suffer damage during that turn, the

opposing player must indicate which borders of the sea zone

contain minefields, and how many minefields are present.


19.63 Sweeping: After a minefield is detected, a minesweeper may

attempt to sweep it. The minesweeper must remain in a sea zone

bordering the minefield for two full turns. Note "sweep" on the

log sheet for the turn. If the minesweeper does not move, fire

(including bombardment and anti-aircraft fire against attacking

planes), or suffer damage during those turns, the owning player

rolls one die for each minesweeper attempting to sweep mines at

the conclusion of the second turn. On a result of 1 the

minesweeper is destroyed by exploding mines. On a result of 2 or

3, there is no effect. On a result of 4, 5, or 6 one minefield

(sweeping player's choice) is removed.



20.0 Motor Torpedo Boats

Some scenarios include motor torpedo boats (MTBs). Although they

go by many names (PT Boats, MTBs, S-Boats) they are all MTBs and

follow the same rules.


20.1 MTB Flotillas

Unlike their First World War counterparts MTBs in the Second

World War operated in flotillas. A flotilla represents the MTBs

assigned to patrol a certain sea zone. Each scenario lists the

total number of MTBs in the owning player's starting forces, the

total number of these MTBs that may be sent out on patrol at any

one time, and the ports and/or MTB bases that the MTBs operate

out of during the scenario. A player may have any number of

flotillas in the game, subject to the number of MTBs sent out on

patrol. A flotilla may have a minimum of one MTB and a maximum of

the total number of MTBs sent out on patrol.


20.2 MTB Deployment

Players record each flotilla number, the number of MTBs in each

flotilla, and the sea zone for each on the Log Sheet. No counters

are placed on the Operational Board. A flotilla may be assigned

to any coastal or island sea zone within two hexes of the port or

MTB base from which the MTBs operate from. These zones may be

part of the same or different coast or island. However the patrol

zone may not have a zone of open water between it and the

originating port or base if that zone is the only way to get to

and from the patrol zone. (MTBs were quite capable of crossing

short stretches of open water on their own between coasts and

islands but to cross longer stretches of open sea they needed a

bigger ship to guide them.)


20.21 Night: MBTs are only sent out at night. Therefore at the

beginning of each night turn that comes after a day turn, the

owning player records the location and composition of each of his

MTB flotillas during the Orders Phase of the turn. The MTB

flotillas stay in their designated sea zones until the beginning

of the next day turn in the game. MTBs are not used during day

turns. (Although MTBs performed many different kinds of missions

during both day and night, it is their primary combat mission of

patrol which occured at night which the game SOPAC is depicting

in these rules.)


20.22 Weather: MTBs are only sent out if the weather is Clear,

Cloudy, or Rain. They are not sent out in Squall, Storm, or Gale.

A flotilla may be sent out on a later night turn if during an

earlier night turn it could not go out because of bad weather but

the weather later gets better. If a flotilla is sent out on a

previous night turn and the weather turns worse in a later night

turn, the MTB flotilla is considered to be inactive during the

turns of weather in which they are not allowed out. (They have

retired to nearby cove or harbor somewhere to wait for the bad

weather to pass.)


20.3 Contact

If an enemy fleet moves into an MTB patrol zone, the MTB owning

player rolls one die for each MTB in the flotilla, making contact

on a result of 5 or 6. There are no modifiers. If contact is

made, the enemy player must reveal the identity of all ships

present. (Flotillas tended to keep their boats apart to gain

maximum area coverage when searching and converged only after

contact was made in order to make attacks.)


20.4 MTB Weapons

Each MTB has two torpedo factors in a deck mount and one special

gunnery mount.


20.41 Torpedo Attack: Once contact is made the flotilla's owner

selects a target ship for each MTB present in the flotilla. More

than one MTB may gang up on a single target vessel. The owning

player then rolls the die to see if the flotilla has surprised

the enemy. On a result of 4, 5, or 6 the flotilla has surprised

the enemy and all boats may make a torpedo attack on their

respective target ships. On a result of 2 or 3 the target ships

may fire only at those MTBs which are attacking them. On a result

of 1 every ship in the fleet may fire at the MTBs.


A ship may only fire its tertiary and AA guns at MTBs, but hit on

a die roll of six (there are no modifiers). An MTB is destroyed

by any hit. Any MTBs which survive the enemy fire may then make

torpedo attacks on their respective target ships. (Due to the

MTB's small size and high speed, warships would only engage them

with their quick firing tertiary guns and AA batteries. They

would not waste rounds from bigger guns nor torpedoes on such

small prey due to the extremely small chance of getting a hit.)


An MTB makes a torpedo attack with all torpedo factors (even

American MTBs before September 1943). A hit is scored on the

target on a die roll of 6, there are no modifiers except for

Aces. (MTBs of the period had rudementary aiming sights for their

torpedoes and had to get in close in order to make an attack,

hence the reason for no modifiers except for Aces.)


20.42 Special Gunnery Attacks: After resolving all torpedo

attacks, the surviving MTBs may at the owning player's option

execute a special gunnery attack on their respective target

ships. If the owning player does not want to make special gunnery

attacks then the MTB attack is over at this point. Those MTBs

whose target ship has sunk may make no special gunnery attacks.

For each surviving attacking MTB roll one die, a result of 6 is a

hit. For each hit roll two dice and consult the Gunnery Damage

Table for effect. Hull and Critical hits are considered to be No

Effect. MTB gunnery can only effect those gun boxes and torpedo

mounts that have no armor. MTB gunnery attacks can not use the

Secondary Penetration rule. (MTBs were armed with machine guns

and Anti-Aircraft weapons and knocked out weapon systems on

warships by causing casualties among the exposed gun and torpedo

crews, not by damaging equipment.)


Should an owning MTB player opt to make special gunnery attacks

on the target ships with his MTBs then every ship in the enemy

fleet may fire their tertiary and AA guns at the surviving MTBs

upon completion of the owning player's special gunnery attacks.

This is regardless of what the owning player rolled when contact

was first made. After all enemy ships have fired, including those

who have fired again, and the results resolved then the MTB

attack is over.


20.5 Ace MTBs

A certain number of MTBs in a scenario may be designated as Ace

MTBs. When a player deploys his MTBs out on patrol he records the

number of Ace MTBs in each flotilla that he sends out. When an

MTB attack is made Ace MTBs add one to the die roll for torpedo

attacks made by their particular boats. When enemy ships fire at

attacking MTBs they can not designate that they are firing at Ace

MTBs only. Instead the total number of sunk MTBs attacking a

particular target ship is tabulated and then randomly distributed

between the Ace and non-Ace MTBs attacking that ship. The same

applies to enemy fleet fire against MTBs during special gunnery

attacks. Ace MTBs have no other effect.


20.6 Restrictions

MTBs may not conduct ASW attacks against submarines or be

attacked by them either. (Yes MTBs did carry a few depth charges

but they were not a proper ASW ship. On several occasions during

the war MTBs did sink submarines, usually with torpedoes, but

these were usually the result of chance encounters and not as

part of deliberate ASW operations.)


MTBs may not attack or be attacked by enemy MTBs. (Okay there

were battles between opposing flotillas of MTBs, especially in

the Atlantic and in the Mediteranian, during the war. However

given the operational level of the game these battles are not

that significant and so are not portrayed.)


20.7 MTB Bases

Besides operating out of major and minor ports, MTBs also

operated out of advanced MTB bases that could be constructed

quickly on recently captured islands. While these bases did serve

as ports for MTBs to be based at, they were also more vulnerable

to shore bombardment and air attack as well.


20.71 Shore Bombardment: MTB bases may be the target of an enemy

shore bombardment. The enemy player merely follows the normal

rules (Rule 9.1) for shore bombardment. However if MTB base is in

a sea zone with other bases as well (i.e. airbases), then the

enemy fleet with the bombardment mission for that sea zone must

have designated on the plot sheet which base it is to bombard for

the mission. An MTB base which has been bombarded may not serve

as a port for MTBs for the remainder of the scenario. However if

the bombardment occurs at night while MTBs assigned to the base

are out on patrol, those MTBs remain out on patrol until the next

day light turn, after which they may not be used for the rest of

the scenario.


20.72 Air Attacks: Air strikes may be conducted against MTB

bases. These follow the rules for Land Strikes (Rule 13.5). An

MTB base has an AA value of 8. It takes four hits to knock out an

MTB base. Hits may be accumulated from multiple air strikes over

the course of a scenario. An MTBs may operate out of a damaged

MTB base until the fourth hit from an airstrike has been scored,

after which they may not be used for the rest of the scenario.


20.73 Base Repair: MTB bases may not be repaired during the

course of a scenario. (Repair materials and supplies usually had

to be brought in by ship and then it took time to put the base

back together, which is usually beyond the time period of most if

not all scenarios in the game.)


Scenario Book

Operational Scenario #7

Add to Allied Forces:

At MTB Base on Tulagi Island (L23)

4 MTBs of which 2 may go out on patrol per night.


Operational Scenario #8

Add to Allied Forces:

At MTB Base on Tugali Island (L23)

8 MTBs of which 4 may go out on patrol per night.


Operational Scenario #9

Add to Allied Forces:

At MTB Base on Tulagi Island (L23)

8 MTBs of which 4 may go out on patrol per night.


Operational Scenario #10

Add to Allied Forces:

At MTB Base on Tulagi Island (L23)

8 MTBs of which 4 may go out on patrol per night.





American Capital Ship Hit Record Sheet

The Australian heavy cruisers Australia and Canberra should each

have a Torpedo Factor of 2. They each should have a point value

of 24.

(Both ships still had their torpedo tubes mounted in 1942. The

Australia had hers removed in 1943 during a refit and the

Canberra undoubtedly would have had hers removed as well if she

had not been sunk. Besides, underwater photographs of the wreck

of the Canberra clearly show that not only did she still have her

torpedo tubes mounted on the ship but that she also fired her

starboard torpedo tubes during the battle of Savo Island where

she went down.)