A Detailed Description

The design goals of the team which created Command at Sea are explained by Larry Bond, in his Author's Note at the start of the Standard Rulebook:

Developing a WWII (historical) game is very different from modeling modern combat. There are reams of historical data available on any aspect of the period. We could easily model all the details of weapons performance, but at what cost in playability? Rather, the goal is ensuring that the results of a game fall within historical limits.

Command at Sea describes actual and hypothetical historical naval and air engagements in WWII. The game system emphasizes playability, both in clarity of rules and speed of play. To compensate for the large number of units present in a WWII game, we worked especially hard on fast, "clean" combat systems, with a minimum of die rolling.

Our goal in this game has been to make play as exciting and fast as possible, without compromising historical accuracy or losing the tactical "feel" of the game.

The game is also exhaustively complete -- not in the sense of needless minutiae, but in the sense that everything a naval wargamer might need is covered somewhere in these rules.

The Sequence of Play

Command at Sea is played using two different types of turn -- Intermediate and Tactical. The game is played in Intermediate Turns (representing a half-hour of maneuvering) until either side comes within visual range of the other, at which time the game shifts to Tactical Turns (3 minutes of combat).

Each Tactical Turn is composed of these Phases:

Plotting Phase Each player writes down movement, firing, and other orders for their units.
Movement Phase Ships move as plotted. Aircraft take a half-move as plotted, and may launch or land.
Planned Fire Phase All weapons plotted to fire now do so. Damage is resolved simultaneously.
Detection Check Phase Players' units check to see if they become aware of previously unseen enemy units. Sensors include sonar, radar, MAD, DF equipment, and lookouts.
Second Air Movement Phase Aircraft make another half-move as plotted.
Reaction Fire Phase Weapons not yet fired this turn may fire. Weapons do reduced damage during this phase. Torpedo attacks may not be made at this time.
Resolution Phase Torpedoes which reached their target this turn now resolve their damage. Also handled at this time are air attacks against ships, and light AA attacks against aircraft.

Ship Movement

During the Plotting Phase, each player writes down his intentions for each of his units. It is not necessary to be overly specific, but just to explain what you want to do; you can also make your instructions relative to what else occurs on the tabletop. Speed changes must also be plotted.

For instance, this would be a legal movement plot: "Close on enemy battleship, turn to parallel its course at 1500 yards."

During the Movement Phase, the ship (or other unit) then attempts to accomplish what has been plotted for it. Each ship has a maximum speed, though this may be reduced due to damage or the sea state. The size and current speed of the ship determines its ability to change speed.

Ships may make turns of 10 degrees or less without penalty. Turns of greater than 45 degrees must be made as two or more smaller turns. Depending on a ship's size and rudder setting (normal or "hard" turn), a ship continues traveling in a straight line for a certain distance between the time the turn order is given and the time the rudder actually "bites." Ships also lose speed when making turns.

Evasive steering allows a ship to throw off enemy gunners by steering an irregular course. The ship's effective speed is reduced, and a penalty applies both to that ship's gunners and to gunners firing at that ship. Very large ships cannot undertake evasive steering.

Specific rules cover these situations:

A two-page article provides background about ship formations and the art of maneuver.

EXAMPLE: Let's say that the John D. Ford (a Wickes-class destroyer) is moving at 30 knots (less than her top speed, but she's part of a formation including slower ships). Add two zeros, and that works out to 3000 yds per tactical turn.

The player now plots a 90-degree left turn using standard rudder, accelerating by 2 knots. In the following Movement Phase, the destroyer advances 300 yards (at 2:1 scale, .3") before the rudder bites, then pivots 45 degrees (the maximum turn allowed at one time), advances another 300 yards (again, .3"), pivots once more for 45 degrees, and then completes her movement (2400 yards, or 2.4").

The DD would normally lose 1 knot for each turn, for a total loss of 2 knots speed, but the acceleration compensates for this.


As the designers explain, visibility "...was such an important part of WWII at sea that playing battles without it produces unrealistic results." Although the game does not require a referee, having one does allow more realistic simulation of unsighted ("hidden") units.

Visibility is set at the start of the scenario at one of eight possible scores, ranging from 100% (60,000 yards) to 2% (1,000 yards). A chart allows scenario designers to determine visibility, based upon weather and light (night or day, phase of the moon).

To determine if one ship sights another, the player consults the correct Visibility Table, correlating his ship size versus the enemy's ship size. (Larger ships are not only easier to see, but can see further due to providing taller observation platforms.) The result is the base sighting range.

This range is modified by a sigma, a random variation reflecting local visibility and condition of the lookouts. The range of the variation depends upon the base visibility conditions. The base sighting range, modified by the sigma, is the final sighting range.

If the target ship is within the final sighting range, it is detected; otherwise, it is not. If the target ship is part of a formation, then all ships of the same class within the same range are also spotted.

These are the rules for visual sighting; other rules explain the use of radar, sonar, direction-finding radio, magnetic anomaly detectors (MAD), searchlights, flares, and starshells. There are even rules for detecting ships over the horizon by means of their stack smoke.

EXAMPLE: During a light rainfall at night (visibility 10%), the Ford has come within 3,000 yards of the Yubari. The referee wishes to know if the American DD has spotted its enemy.

On the 10% Visibility Table, the Ford (a DD) can spot the Yubari (a CL) at 2800 yards. This is the base visibility. Rolling a D10, he finds the sigma to be +1, raising the sighting range to 3800 yards. Since the Japanese CL is within this range, it is spotted by the Ford.

But does the Yubari spot the Ford? The base visibility is the same (2800 yards), but (roll the dice!) the sigma is 0 (no modifier) -- the Japanese CL does not see the American DD.


The Data Annex lists which guns each ship has. Before play, each player fills out his Ship Data Form based on this information. For example, here is the gun listing for a Wickes-class destroyer:

    Mk22 3 in 76mm/50                                C
What does this mean? First, it tells us that the DD's main guns were Mk22 3 in 76mm/50's, and that there were six Mounts (gun locations), each of which had a single gun tube.

The location of the gun mount determines in which direction the individual gun mounts can fire. The "F/PB&P/P&PQ/SB&S/S&SQ/A" tells us that one gun fires into the forward arc of the ship, the next gun fires in both the port and port-bow arcs, the third gun fires into the Port and Port Quarter arcs, and so forth.

The "C" at the end of the data entry tells us where in the Data Annex we can find more information about this weapon. Including here are the range bands, dividing the gun's range into short, medium, long, and effective ranges.

The rules do not track ammunition usage; each gun is assumed to have an infinite ammo supply.

Gun Directors. All six of the example DD's guns are controlled by a single gun director. In battle, each gun director can only handle one target at a time. Therefore, if the destroyer wishes to engage more than one target at the same time, some of the guns must fire under local control (losing the benefits of the gun director, such as greater sighting range). Guns can only fire under local control if ordered to do so in the Plotting Phase.

The Attack. As mentioned above, guns can attack either as a result of a plotted order, or "at will" during the Reaction Fire Phase (but doing less damage than plotted gunfire). Each gun may only attack once per turn.

A gun cannot fire if it does not have a valid Line of Fire (LOF) to its intended target. Land or ships (friendly or enemy) can block LOF. Guns firing in proximity to catapult-mounted floatplanes risk damaging the plane and possibly their own ship.

When an attack is declared, the range between the firer and target is determined to discover which range band the gun is operating within. In this game system, all attacks at a given range band have the same chance of success -- for instance, all attacks at short range have a base chance of 90% to hit their target. Short range, however, will be different distances for different types of guns.

The base chance to hit is modified by these factors:

The Modifiers Table includes brief notes explaining each modifier. For instance, there is a penalty for Japanese ships firing while making major course changes, with the note "...they lacked 'stable elements' in their fire control systems."

EXAMPLE: Let's say that our old friend, the John D. Ford, has plotted to fire on two Japanese destroyers to port -- the Asashio, on a parallel course at 12,000 yards, and the Oshio, which has just turned to make a charge and is at 7,000 yards.

The fore, aft, and both port-side guns can bear; only the SB&S and S&SQ guns cannot see either target. For purposes of this example, the Ford's commander orders two mounts to fire at either enemy. Becuase there is only one gun director, only the fire against one target (the Asashio) will be under director control; the other two gun mounts will be firing under local control.

The attack against Asashio is at 12,000 yards, or long range for this gun type (30% base chance to hit, or a "3" or less on a 10-sided die). This is modified by -1 (target at high speed) to a "2." On a die roll of "8," the gunfire against Asashio fails to score a hit.

Both attacks against the Oshio must be made individually, since the two gun mounts are firing under local control. The basic chance to hit is 60% (medium range), halved to 30% due to being in local control. This is modified by -2 (narrow target aspect, since Oshio has her bows to the Ford), for a final chance of 10%. The Ford's player rolls twice, scoring a "9" and a "1" -- one hit.

Torpedo Combat

Again looking at the data for the Wickes-class destroyer, we find this entry:

P/S(3)2 533mm TT                             E
What this means is that the destroyer has two torpedo mounts, each of which comprises three launching tubes. One mount fires to port, and the other fires to starboard. They fire the 533mm torpedo, found in Data Annex E.

A surface ship can fire its torpedoes if it has plotted to do so, and if it does not excessively maneuver while firing. During the Planned Fire Phase, the point of launch is marked (either secretly by the referee, or by placing an Datum counter on the tabletop), and the depth (shallow or deep) and course (i.e., 25 degrees) is recorded. For some torpedo types, speed can also be selected.

Selecting the course is the important part, since science as well as tactics is involved when trying to hit a moving target. Command at Sea provides a set of tables to help with this chore. By correlating the target's speed and angle with the torpedo's speed, one obtains the recommended deflection angle for the torpedo -- in other words, where to aim the torpedo so that it will intercept the ship, assuming the ship doesn't change course.

If a torpedo mount has more than one tube, it can fire its torpedoes as a spread. A spread of torpedoes is treated as a single torpedo, except that it has increased chances of hitting its target.

Once launched, a torpedo moves during the movement phase until it either runs of of fuel (exceeding its range) or comes within 500 yards of a possible target. (An optional rule chnages the danger range, depending upon distance travelled and the number of torpedoes in the spread.)

When a torpedo comes within danger range of a ship, the combat resolution procedure begins. The apparent size of the target ship (actual size modified by angle of attack), the distance travelled by the torpedoes, and the number of torpedoes in the spread determine the chance of the attack succeeding, and even indicate how many of the torpedoes in the spread impact. (Torpedoes which fail to impact continue on their way.)

This description applies to straight-running torpedoes, but rules are also provided for pattern-running and acoustic homing torpedoes.

EXAMPLE: Continuing our example, let's say that the Ford has also plotted to fire a spread of torpedoes at the Oshio. (She can only fire one spread, since only one mount fires to port.) The American DD cruises in a straight line, making torpedo fire possible.

The player decides to set the torpedoes to run shallow. Assuming that the Oshio doesn't change course, no deflection angle is needed -- the Japanese DD is coming straight toward us, so we can fire the torpedoes straight at it.

The mount has three loaded tubes, so three torpedoes can be fired in this spread.

The referee notes the torpedo spread's point of origin and current position (keeping it secret from the opposition). If no referee is available, the rules suggest that players plot their movement several turns in advance, so that they don't (consciously or unconsciously) cheat when they "see" an unsighted torpedo's counter on the tabletop.

The torpedo spread begins its movement in the next movement phase, continuing until it runs out of fuel or runs into someone.

In the course of time, the torpedo spread comes within 500 yards of the Oshio. The Japanese DD is a small target (class C) at narrow aspect (bows toward the torpedoes), which tells us to resolve the attack on Table VI. The torpedoes have traveled 3500 yards, and there are 3 torpedoes in the spread, so the chance of a successful hit is 8% (with no chance of multiple hits). Rolling percentile dice, the player scores "02" -- a lucky hit!

Ship Damage

As a ship takes damage, it moves slower and risks the chance of a Critical Hit. When it has lost sufficient damage points, the ship sinks.

Gunnery Damage. A Damage score is given for each gun at each range band. When an attack succeeds, the total damage is the Damage Score multiplied by the number of gun barrels in the attack.

If the target ship is armored (which most ships above destroyer class are), there is a chance that the attack will not penetrate the armor. Each ship has two armor values -- belt (used against attacks at close or medium range) and deck (used against gun attacks at greater than medium range, which are considered "plunging fire"). Each gun also has a Penetration Value listed for each range band. If the Penetration is less than the Armor, then the damage from the attack is reduced by at least half.

EXAMPLE: In our previous gunnery example, the Ford got a single gun hit on the Oshio. The data tables tell us that this gun does 9 points of damage at this range. Since the Oshio has no armor, it must take the damage -- but this is not enough to reduce the Japanese DD's speed (it has 75 total damage points).

For the point of the example, however, let's say that the gunnery hit had been against another ship -- the Yubari, a light cruiser. Since this target is armored, we have to determine if the attack penetrates. Since the attack was at medium range, the defender uses its Belt Armor rating of 4. (At longer ranges, the Deck Armor of 3 would apply.) At medium range, the Ford's guns have a Penetration of 3 -- not enough to penetrate. At this range, non-penetrating damage is reduced by two-thirds, so the hit does 3 points of damage instead of the usual 9.

Torpedo Damage. Like guns, torpedoes have damage scores which apply when they successfully strike their targets. If a ship has belt armor, the damage is reduced; if the target is struck directly from the bow or stern, armor does not apply.

Special rules apply to ships with torpedo bulges, a protection system designed into the construction of the ship.

EXAMPLE: In our previous example, a torpedo from the Ford struck the Oshio. Assuming that the torpedo is a Mk. 15, the damage done is 125 points. Because of the angle, armor does not apply (besides, the Oshio has no armor). This is enough damage to cause the Japanese DD to begin sinking.

Critical Hits. In any phase in which a ship takes damage, there is a chance of a special damage result -- a Critical Hit.

To determine this, the Damage Ratio must be computed. This is the damage taken this phase, divided by the ship's remaining strength. Looking this value up on the Damage Ratio Table and rolling a die indicates how many Critical Hits the victim suffers.

To determine the exact Critical Hit, the player makes a dieroll on the Critical Hit Table (there is a different table for each type of ship). The individual results may require additional dierolls. The possible results are:

Certain Critical Hits are ignored if none of that phase's damage penetrated the ship's armor.


Special movement rules apply to submerged submarines, which can be at one of several somewhat abstract depths (periscope, shallow, four grades of intermediate depth, and deep). Other rules determine the effect of battery charge on sub movement.

Submerged subs are primarily detected by sonar. Depending upon the sensor, sonar can operate in pasive or active (capable of being detected) mode. Sonar units can be hull-mounted, bow-mounted, keel-mounted, deck-mounted, or flank-mounted, all of which have different blind zones or "baffles."

Surface ships can attack submerged subs by means of depth charges or ahead-thrown weapons. A ship's launching equipment (racks, rails, "K" or "Y" guns) determine the rate at which depth charges can be thrown, and influence what type of patterns can be laid. The attack result takes into consideration such factors as sink rate and size of warhead.

Submarine torpedo attacks work the same way as torpedoes fired by surface ships, although special rules explain how to reload torpedo tubes and the necessity of specifying torpedo load-out before play.

Subs can also fire their deck guns while surfaced, if truly desperate.


Extensive rules (20 pages) apply to aircraft operations. When necessary (usually when opposing aircraft are in close contact), the game can break into mini-turns, known as Rounds (representing 30 seconds apiece).

Air-to-Air Combat. In order to attack one another, aircraft must perform a Dogfight maneuver. Once a dogfight has been initiated, the exact location of the aircraft involved in that "furball" is no longer tracked. Instead, the center of the dogfight is tracked.

If the dogfight involves non-dogfighting planes (such as bombers attacking a carrier), the Dogfight marker conforms to their movements; otherwise, the Dogfight moves randomly about the battle area. If a plane chooses to leave the Dogfight, it is placed at a random location near the Dogfight marker.

During combat, each attacking plane (acting in Maneuverability order) attempts to maneuver into position against a semi-randomly chosen enemy. If the maneuver is successful (based on the Maneuverability of the two planes), then an attack can be made. Comparing the attacker's Gun Rating vs. the defender's Defense Rating on the Air-to-Air Combat Chart reveals the percent chance of "knocking out" that aircraft.

As an option, planes may instead make slashing attacks rather than risk a prolonged Dogfight. There is also an optional combat system for more quickly resolving very large air combats.

EXAMPLE: During a swirling dogfight, a surviving Wildcat F4F-3 finally gets to attempt its attack (due to its low Maneuverability, all of the enemy Zero's make their attacks first). The American player is given a choice of attacking two randomly chosen targets, which turn out to be a Zero or a Val -- he selects to go after the Val D3A2.

Comparing the Maneuverability ratings of the two planes, the Wildcat's chance to get into attack position is 3 (Wildcat's Maneuverability) - 1.5 (Val's Manueverability while heavily loaded, with bonus for flying defensively) + 3 = 4.5 * 10 = 45%. On a dieroll of 19, the Wildcat succeeds.

On the Air-to-Air chart, the Wildcat's Gun Rating (1.5) vs. the Val's Damage Value (6) reveals a 34% chance of shooting down the target. On a roll of 61, the Wildcat fails.

However, the Val has defensive guns, and also gets to make an attack. Its defensive gun rating (0.5) vs. the Wildcat's Damage Rating (8) results in a 12% chance to shoot down the attacking fighter. A roll of "24" just isn't good enough, and the Wildcat survives.

Anti-Aircraft Guns. Ships have two classes of anti-aircraft guns -- area and light AA. Light guns can only attack planes which are attacking their ship. Area AA has a greater range, and so can be used by one ship in defense of another.

If the guns have targets, they may fire. However, they are as likely to hit friendly planes as enemy targets. (Therefore, keep friendly planes out of range, or withhold AA fire when friendlies are around...)

Certain circumstances modify the chance to knock down an airplane, including: target altitude and speed, visibility, and the maneuvering of the firing ship.

EXAMPLE: Our faithful Wickes-class DD has the following anti-air armament:

Area AA: (1)6 Mk22 3 in 76mm/70           (1.7)
Light AA: 1(4) .50 cal                    (.3)

What matters here are the final numbers -- an Area AA strength of 1.7 (representing the ship's main guns firing in an anti-air role), and a Light AA of .3 (the air-defense machineguns).

Let's say that two enemy Kates are attacking a nearby carrier, closely pursued by a friendly Wildcat fighter. Our DD fires to try to knock down the bombers. Only the Area AA can fire, and since all of the targets are on the same side of the ship, only half the guns can fire (half strength, or 1.7 / 2 = .85). There is a +1 modifier to the dieroll (target at low altitude).

The American player rolls a "7," modified to an "8" due to the +1. On the ".85" column on the Combat Chart, this reveals that 2 planes are shot down.

The players alternate selecting which potential targets have been shot down. The American player removes one Kate, and the Japanese player removes the unfortunate Wildcat.

Anti-Shipping Attacks. The rules cover dive-bombing, level bombing, skip bombing, aerial torpedoes, strafing, kamikaze attacks, and (late war) guided missiles and rockets.

Dive bombers normally attack in formation, and have the option of releasing their bombs at the standard altitude, or to go down to "masthead" altitude in order to increase their accuracy (but posing a greater risk of being knocked out by AA before being able to attack, and reducing the bomb's penetration).

When resolving the attack, the primary factor is the number of bombs dropped, chiefly modified by the size and speed of the target. A dieroll reveals how many bombs are "hits."

Aircraft Operations. Rules detail the launching and landing of aircraft from carriers, and the handling of aircraft within the ship (respotting, refueling, rearming). An optional rule covers landing accidents.

Once the planes are airborne, mission planning becomes essential. Rules cover aircraft range as modified by ordnance load and expected fuel consumption, as well as repair and maintenance. Cruising speed and altitude determine fuel consumption.

Very Low altitude flight is dangerous, and Crash Rolls may be required depending upon the situation. Other rules cover landings and takeoffs from runways, the operation of amphibians and flying boats, and the launching of floatplanes from catapults.

Last Updates
24 June 1996reformatted
15 April 1996reorganized
Comments or corrections?