From Moves#11 


Adding Simultaneity 

by Jerrold Thomas 

"CA" represents a departure from other naval surface combat games. It
has much less of the miniatures game in it than do most naval games.
Partly because of this, and partly because it does build on existing
systems, it plays much more smoothly and rapidly than do most naval
tactical games, yet without losing interest and excitement. 

It's greater simplicity lends itself to two things: 

1. "CA" will be
provocative of variants because all of the essentials are presented in
a remarkably simple, and easily built upon format. 

2. The "CA" system can be integrated with land operations without
introducing hopeless complexity. 

The only aspect of the "CA" game-system which I feel could use some
improvement is the Torpedo Combat Procedure. Here the abstraction in the
CRT becomes a significant deviation from reality. 

In "P" and "W" gunnery results, a broad range of possible outcomes, from
one critical hit to many not-so-critical ones, is abstracted to give a
net effect. The obvious premise is that one shell will not sink a ship,
but that a range of combinations can have a sum effect on a ship's
performance. When, say, two CA's slug it out, both will score some hits,
but that does not say that these hits will or will not affect the combat
performance of the ship hit. The "CA" Defense Strength, based on ship 
"protection," is thus a good gauge of a ship's relative resistance to
gunfire (in the abstract sense). 

In torpedo combat, however, such a broad range of results does not
exist. Torpedo combat is an "either-or" situation, either a ship is hit,
or it is missed. A ship's armor protection has no positive relation to
that ship's chances of being hit with a torpedo (in fact it has a 
negative relation, since more armor means a larger and less maneuverable
ship), and has relatively less relation to how a ship will survive a

As an example, the Yamato has a Defense Strength of 36, the Kagero a
Defense Strength of 2. While 1 torpedo would sink the Kagero, the Yamato
obviously would not require 18 torpedo hits to be sunk (it actually took
12 hits, but several of these were probably "overkill"). The key
parameter in torpedo combat then becomes whether or not the given ship
will be hit by an attack. Factors affecting the chances of getting a
torpedo hit on a ship were: 

1. The torpedo crew's skill in setting torpedo solutions, 

2. The relative speed of the torpedoes, 

3. The number of torpedoes

4. The range to the target, 

5. The relative direction of the target's movement, 

6. The velocity of the target's movement. 

The "CA" Torpedo Strength already makes allowance for factors # 1, 2,
and 3; also current "CA" rules clearly take #4 into account. I
considered #5 as being included in the current rules for two reasons: 

1. Ship facings relative to each other are ignored for gunnery combat,
and would be impossible to add without introducing unacceptable

2. The Attack-Movement Phase order assures that a ship moving away from
an attacker will have increased his distance from the attacker prior to
the attack, thus lowering the attacker's Strength in many cases. 

Accordingly, relative vulnerability to torpedo attack, as far as scoring
torpedo hits is concerned, becomes dependent on velocity. This is
reflect in a new... 


1. Compare the sum of the attacking ships' torpedo strengths to the
defending ships Torpedo Evasion Value - TEV (correcting for any range
effect on the torpedo strength), to establish a basic odds; round this
odds off downward to one of the simplified odds on the CRT. 

a. A ship's Torpedo Evasion Value - TEV - is equal to its current speed,
(taken from its speed/facing marker), plus 1; i.e., a ship DIW has a TEV
of 1, a ship moving at speed 5 has a TEV of 6, etc. 

2. Roll the die once for each battle against the Combat Results Table - 
CRT - under the appropriate odds column. The CRT results have the
following meanings for torpedo combat: 

a. a "P" or "W" result indicates one torpedo hit on the defending ship; 

b. a "PW" result indicates two torpedo hits on the defending ship. 

3. If a hit or hits are secured, the die is rolled again, for each
battle in which a hit (or hits) was secured, against the Torpedo Hit
Chart, cross-indexing the die roll with the number of hits secured and
defending ship Defense Strength (from the ship counter). 

The Torpedo Hit Chart results are the same as those given under the CRT,
except for:

"2P" indicates that the defending ship receives 2 Power hits; 

"S" indicates that the defending ship is sunk, and removed from play. 

The data on which the Torpedo Hit Charts are based is found, partially,
in the Torpedo Hit Results, 1942-43 table. This table was compiled from
fifteen actions involving torpedoings, from the Java Sea battle,
2/22/42, to Empress Augusta Bay, 11/2/43; both Allied and Japanese
results are shown. The results are expressed in terms of how many ships
of each type received a given number of hits in one of the engagements,
and what the impact of that number of hits was on the ship in terms of
"CA" combat results. In many cases ships were also hit by gunfire, but
it is impossible to accurately reflect relative damage contributions. 

The table is explained as follows: In the engagements covered, for
example, 15 DD's received one torpedo hit; of these, 13 sank in the
engagement hit, 1 was DIW, and one suffered damage equal in "CA" terms
to a "PW" hit. 

The table makes several things apparent which are not reflected clearly
in the game or article. First, one torpedo hit had a much better than
even chance of sinking a DD (85%?). The only two exceptions, Selfridge,
and Foote, were both hit on the extreme ends. Foote was hit on the
stern, lost it's stern section and screws, and was DIW; Selfridge was
hit on the bow, and lost its bow section with two turrets, and could
make only about 10 knots. Contrary to the article, Chevalier sank after
a single torpedo hit which removed her bow section somewhat further back
than in the case of Selfridge.

This brings up another aspect of torpedo hits which I have attempted to
incorporate. In a significant percentage of these hits, the bow sections
of ships up to and including CA's would be blown off, removing the bow
turrets and drastically slowing the ship if it was not sunk.
The "CA" equivalent of this would be "PW," but this is impossible
under the present system. The "PW" results on the Hit Chart also reflect
the fact that a ship's fighting power was intimately linked to its
motive power the boilers that turned the screws also turned the turrets.


Another area of "CA" which can be improved is its reflection of the
great changes in American doctrine, training, and technology in the
period 1941-45. Also, improvement can be made in reflecting significant,
unusual conditions which existed in individual scenarios. Accordingly,
the following special rules are proposed: (for scenarios after 8/1/43):

1. USN ships have a primary torpedo range of 4. 

2. USN can use FCR (fire control radar) on ships at 10 hex range which
are not "spotted." All firing ships must fire at the nearest, or the
larger if two are equally close, enemy ship all firing ships are spotted
as per "CA" rules. 

Scenario Special Rules 

Scenario 2 - Savo Island 

1. U.S. Cruisers, once hit, are permanently spotted (this reflects the
presence of unprotected fabric spotter planes and gas on deck). 

Unless IJN ships come within 4 hexes on turn 1, U.S. ships may neither
attack nor change course or speed. [Note.. even these additional rules
cannot fully simulate the extent of American unpreparedness at this
point; the actual battle was a 43-0 Japanese Victory]. 

3. The CA-2 (IJN) has a Torpedo Strength of only 20, but may reload

Scenario 4 - Guadalcanal 

1. USN ships are moving at speed 3 to start. 

2, If IJN score over 10
bombardment points, they may extend the scenario to 20 turns. If they
score over 30 bombardment points, only IJN ships actually sunk are
considered sunk. 

Scenario 6 - Tassalaronga 

1. The IJN Player may score the special rule points only once for each
(s) DD unit. 

2. DD units marked with an (S) have no torpedo reloads. 

Scenario 7 - Kolombangara (corrections only) 

1. The IJN ships are
moving at speed 5. 

2. The USN ships are moving at speed 6. 

3. There are only 2 Craven DD's in this scenario. 

Scenario 8 - Empress Augusta Bay 

1. Movement visibility is 10 hexes this scenario only. 

2. USN ships are moving at speed 4, IJN at speed 5. 


Below are two new scenarios; one an inconclusive DD action, and the
other a "Tokyo express" situation. 

Scenario 11, Kula Gulf, 7/6/43 

LAND - Configuration "C" (Guadalcanal 
portion only) 

IJN Player 

Hex	Ship		Speed/Course 
2826	2 Kagero DD-4	5/n 

2828	2 Shigura DD-3	5/n

2829	2 Fubuki DD-2	5/n 
2830	(t)

2831	2 Mutsuki DD-1	5/n
2832	(t)

USN Player 

Hex	Ship		Speed/Course 

3718	2 Fletcher DD-6	5/nw

3919	3 Brooklyn CL-3	5/nw

4220	2 Fletcher DD-6	5/nw

Game Length - 20 Game-Turns or optionally 30 Game-Turns with 

Reinforcement - IJN Player 

3 Mutsuki DD-1(s) on south edge within 5 hexes of land, speed 5, course
n, enter turn 20. Use Tassafaronga special torpedo rule. 

Victory Conditions - victory is awarded on a points basis; points are
obtained in accordance with the following schedule: 

CL sunk = 6 pts.	DD sunk	= 3 pts. 
CL DIW = 4 pts.		DD D1W	= 2 pts.
CL P hit = 2 pts.	DD P hit = 1 pt. 

Japanese ships DIW at game
end are considered sunk. The IJN player begins the game with 6 points, as
the supply (s) ships have unloaded. Each (t) DD has 1 point worth
of troops on deck; if the DD leaves the map unhit, the IJN player
receives this point, if the DD is hit, neither player gets this point;
if the DD is sunk, the USN Player receives this extra point. 

The level of victory is determined by the ratio of victory points,
IJN/USN as follows: 

Level of Victory	Ratio IJN/USN 
IJN Major		5.00 up 
IJN Minor		3.00-4.99 
Draw			1.50-2.99 
USN Minor		.75-1.49 
USN Major		.74 or less 

Scenario 12 - DD Action off Horaniu 8118143 (Vella LaVella) 


IJN Player 

Hex 	Ship		Speed/Course 
4612	2 Kagero DD-4 	3n
4514	1 Kagero DD-4 	3/ne
4316	1 Fubuki DD-2	3/n
4317	1 Kagero DD-4	3/n

USN Player 

Hex	Ship		Speed/Course 
3726 	4 Fletcher DD-6	7/nw 

Game Length - 15 Game-Turns. 

Victory according to point schedule on Scenario 11; point ratios as per
table on Scenario 3. 

UN ships DIW at game end are considered sunk. If either side leaves map
before Game-Turn 10, the opposing side wins. Spotting Range is 16 hexes,
this scenario only. 


Because "CA" already incorporates the two essentials for SMS - 

1. Few (generally less than 20) units per player at any one time, and

2. the standard coordinate grid, 

it is comparatively easy to shift "CA" into an SMS format without
changing the rules substantionally (For those who are not familiar with
the term, SMS is SPI's new Simultaneous Movement System, which uses a
pad that is the same for all SMS games). 

The following are the rule changes necessary to use SMS with "CA". 

SEQUENCE OF PLAYER (4.0) When using SMS, the sequence of play is changed
as follows: the basic change is that there are no longer any
Player-Turns; both players perform the same actions at the same time. 

A. Sight Determination Phase - Players determine which ships, if any,
are "spotted" by opposing forces; firing ranges are determined for
gunnery and torpedo combat. 

B. Operation Plot Phase - Both players secretly plot the operations of
all of their units in accordance with section (10.0), indicating all
movement, gunnery and torpedo attacks. Spotting and firing range is
established for any previously unspotted ship that elects to use its
Gunnery Attack Strength. 

C. Board Movement Phase - Both players maneuver their units on the map
in accordance with the instructions written on their SMS Plot Charts,
Units not visible to the enemy are maneuvered with both the ship counter
and the speed/facing marker inverted; the opposing player may not
examine these counters. 

D. Combat Resolution Phase - Both players, in any order, resolve all
gunnery and torpedo attacks. All combat is considered to be
simultaneous. Result counters are placed, but results do not take

E. Combat Results Application Phase - All combat results take effect
simultaneously. Ships accumulating three (3) hits of any type(s) are
considered sunk, and are removed from play at this point. 

F. Game-Turn Indication Phase - Players indicate the passage of one
Game-Turn; availability of reinforcements (if any) is determined;
victory point records are adjusted. 

Play then reverts to Phase A for the next Game-Turn 


General Rule. 

In order to create the lack of intelligence of enemy intentions, players
initially plot (write down) their intended movements and attacks in
secret from their opponent, who is thus unaware of what is planned until
it takes place. 


During the Operation Plot Phase, players plot, on the SMS Plot Chart,
the movement of all their units, and indicate which units are making
gunnery and/or torpedo attacks, and the target of each attack. 


[10.11] Place each ship's Unit I.D. (composed of the ship type and Class
Name codes from the ship counter) in one block in the "UNIT" column of
the SMS Plot Chart. The row of numbered blocks following each ship's
unit I.D. will be used to plot the movement and combat for that ship
that turn. 

[10.12] In the next block(s), place one attack code (if the ship is to
attack in that turn) and indicate the Unit I.D. of the target ship. If a
ship is to make both gunnery and torpedo attacks in a given turn, then
two attack blocks will be required. 

[10.13] Following the blocks in which attacks have been recorded (if
any) plot the movement of each unit, recording each hex to be entered by
the unit in this turn. If the unit will expend movement points turning
in a particular hex, place a circled number in the block with the hex
number to indicate how many movement points were expended in turning.
See (6.0) Movement for details on how to move. 

[10.14] After all of the movement points of the unit have been expended,
in the next block, place the final speed/facing of the unit, i.e., the
speed facing after completion of all turning, acceleration,
deceleration, etc.; this becomes the initial speed/facing for the next


[10.21] An attack code written in a block with a Unit I.D. commits the
given ship to make the indicated type of attack on the indicated target.
The attack codes are "G" for gunnery attacks and "T" for torpedo
attacks. Attacks are made subject to the limitations of section

[10.22] Decisions regarding combat are final. No changes in attacking
units or target units can be made after the end of the Operation Plot


Each player's Simultaneous Movement Plot Chart is to be hidden from the
other player until the end of the game. If there is any question about
the other player's orders, the Player is advised to write them down and
compare them with the SMS Plot Chart at the end of the game. A player
who secretly violates the rules to gain an advantage in the game,
forfeits that game. 


[10.41] All combat is considered simultaneous. For this reason Combat
Results are not effective until the Combat Results Application Phase.
Then they are applied to all units that suffered them. 

[10.42] A ship that suffers a Combat Result in a given Combat Resolution
Phase must engage in combat in that phase if ordered to do so by the SMS
Plot Chart without any consideration of the Combat Result. The Combat
Result does not affect the ship's combat ability in any way until the
Combat Results Application Phase of that turn. 


All movement is also considered simultaneous. Both players execute all
plotted movement during the Board Movement Phase. All plotted movement
must be executed; ships may never alter their movement in response to
enemy actions. 


[7.61] Most scenarios in "CA" take place at night. There are special
restrictions upon firing at night. Ships may only fire guns or torpedos
at target ships that are "spotted." 

[7.62] Spotting occurs in three manners: 

(a) Whenever a ship uses its Gunnery Strength in a turn, place a spotted
marker on it. Torpedo attacks do not cause spotting. 

(b) Whenever a ship is within eight (8) hexes of an enemy ship, place a
spotted marker on it. 

(c) Whenever a ship has been the target of a gunnery attack in a turn,
and fulfilled the conditions (a) or (b) above, it remains spotted for
the following Game-Tum only, if it is again under under gunnery attack,
even though it does not fulfill the requirements of (a) or (b). 

[7.63] Spotting is determined only in the Sight Determination Phase.
Ships which fulfill the sighting requirements in that phase, and ships
which make gunnery attacks (see 10.31) are spotted for that turn.
Because spotting is only determined in the sight determination phase,
the initial contact between two ships may be made at less than eight

[7.64] Spotted markers are removed at the end of each Game-Turn. 

Those are all the rule changes necessary to play "CA" in Simultaneous
Movement. For those players willing to put up with some slight
additional complexity, the Simultaneous Movement System can be used to
add a crucial factor to the game - the simulation of
preparedness/alertness, which is crucial in all naval combat, but is
particularly important at night. The method for doing this will be
discussed in a later article if feedback response warrants it. 

Shown, is an example of how to fill out the SMS Plot Chart as indicated
in the rules. 


Indicated is the first turn plot for the Allied Player in Scenario 1A.
In this case, the first hex of placement is written down because the two
capital ships expend their Movement Points turning in this hex;
otherwise this hex would not be written down, as the information is
given with the scenario. The two capital ships attack the IJN BC's,
though the combat is ineffective because of the range (it is merely
included to show the mechanics). No torpedo attacks are made this turn.
The Allied Player increases the speed of all his ships, and maneuvers to
close the range. 

NB submitted by John Kula (
on behalf of the Strategy Gaming Society
originally collected by Andrew Webber