Summary of how the game works

The essence of the game, or indeed any naval wargame, is the amount of damage each ship can take. Pratt added together the standard displacement of the ship and points based on its armour, guns, speed etc. according to a simple, but elegant formula. Typically, destroyers have values between 5,000 and 10,000 points, cruisers between 25,000 and 80,000, and battleships between 100,000 and 150,000 points.

The guns the ships carry inflict damage approximately in proportion to the weight of the shell fired by the gun. So five inch destroyer guns do 160 points damage per hit, while the 16 inch guns of a battleship inflict a staggering 10,550 points per hit. The values for ships and the gun damage was largely based on close study of the battle of Jutland.

As the game progresses, the ships take hits, with each hit being deducted from its initial point’s value. The speed and offensive power of the ship decreases in direct proportion to the accumulated damage. So when a ship has received damage equal to half its point value, half her guns (of each calibre) are out of action and her speed is reduced by 50 percent.

The speed and guns remaining to a ship are determined by references to a pre-generated ship card, on which is a table of damage and effect. Below is an extract from a ship card for a British battleship.

BB King George V Class (class includes KG5, Duke of York, Anson, Howe) RN battleship

Guns 10 * 14” guns range 74" 16 * 5.25” guns AA 134 guns
Torpedo Tubes 0 points value 143,047
Armour Turret 8.5 Planes 3
Belt 9.75 Speed 29 kn
Deck 4.2 Tonnage 33,900

Damage received knots
4,933 28
9,865 27
17,881 -2 * 5.25" secondary guns
47,682 -1 main turret (4 guns)

Until

Damage received knots
133,182 2
138,114 1
143,047 wrecked

If this ship were hit by one 16 inch shell (8,550 points damage), its speed would be reduce to 28 knots (last entry on the card above 8,550 points). After four more 15 inch hits, damage would be enough to knock out a main turret (which turret is determined randomly). Each additional hit then adds to the cumulative damage until the ship is sunk or the battle has ended. As a ship slows down, it becomes easier to estimate the change in its position and so players find it progressively easier to finish off a damaged ship.

At shorter range, hits often penetrate the target's armour. If a hit does not penetrate the armour, the ship takes half-damage. Pratt determined that hits on ships that are broadside to the firing ship are assumed to strike the belt armour. Hits which strike ships from end-on, strike the thinner deck armour. A chart relating the size of gun, thickness of armour against the range was used to determine if the armour has been penetrated.

How the Game is Played

Each player is given a ship card with the relevant details and a measuring stick for movement plus some firing arrows. The ship card is used to show the speed of the ship, the number and calibre of the guns, their range, the damage they do and to record damage to the ship. Each turn has three parts: A moving phase, a shooting phase and a measuring phase.

Moving

Each ship is moved against a measuring stick with knots marked on it. Each division of the scale represents one knot of speed. In the halls Pratt used, it was 14 millimetres to the knot. However in these rules, ¼ inch per kn is used to allow the game to be fought on a normal sized domestic room.

A ship must always move at least two knots so long as it is able. It may make a turn of up to 90 degrees during any move, This turn must be made in a natural arc using all the length of the move. A ship may not make an abrupt 90 degree turn, then proceed further in a straight line. A turn may be a "S" type shape, providing the total amount turned is less than 90 degrees.

The game uses what was probably the first wargaming battlefield, the floor. In this case the floor represents the sea.

Shooting

The essence of naval combat, and hence the game, is naval gunnery. This is done by the simple method of laying firing arrows pointed at the target with an estimate of the range in inches written on them. Large numbers of firing arrows are needed in a game, but they can easily be made out of spare cardboard. The convention of the rules is that the first round of each salvo is assumed to fall at the range written. Each of the remaining shells then falls one inch nearer the firing ship. Of course, a ship’s captain can set any interval they wish, or if particularly confident, can specify all the shells to land at one particular range.

Torpedoes are fired during the moving phase, before the firing ship has moved. The torpedo direction is indicated by placing a pointed card adjacent to the position of the torpedoes on the model. It is marked with an arrow to indicate the course of the torpedoes. All ships move, then the torpedoes are moved. They have a standard life of four moves and move at 38 knots (9 inches per move). A ship is hit if, at the end of any move, its hull is touched by the path of the torpedo travelled on that move. This may seem arbitrary (it is), but in practice it works well. Torpedoes cause heavy damage, but as in actual combat, it is very difficult to hit an alert enemy.

Measuring

Pratt had the players leave the room during the measuring phase and then the referees measure shots and determine hits. However, having the players stay (at a suitable distance) and see their hits measured is quite fun. When there are only a few players, they can measure each other's shots.

The referee should measure the range from the bow of the firing ship towards the target. Practise indicates the angle of the shot should be taken as the line between the funnel and the tip of the firing arrow. Shots which fall on the target or no more than half inch beyond, are hits. Shots that fall short are counted as a miss. Fall of shots are marked by upside-down golf tees, red for hits, white for misses.

The referees calculate the damage done to each ship and reports it to the player acting as captain for the ship. Normally, letting the captain do the necessary maths on their ship card frees the referee to move onto their next task. This delegation helps maintain the pace of the battle. By reference to the golf tees, each player can observe the approximate results of their shooting, but just as in real sea battles, they judge the effect of their shooting by the amount of fire coming back. The game ends when all the ships on one side are disabled or one side has successfully broken contact and sailed away.

(This overview is based upon the original rules by Fletcher Pratt and the summary by Donald Featherstone in his classic book, Naval Wargames, 1965)