Guns

Guns are the primary armament of most ships.

## General Principles

Guns range in size from 2" to 20", and in quality from -2 to +1. The size of a gun affects its range, penetration, damage, and the mass of its gun mount and ammunition. The quality of a gun affects range and penetration as well. As a rule of thumb, one quality level will increase range and penetration roughly as much as one inch of calibre, but without any weight increase.

### Flash Fires

Guns may occasionally be the victim of flash fires, where an unlucky hit makes it to the gun's magazine, detonating it. This destroys the ship instantly. The mechanics on this are somewhat uncertain (see this thread, for example). Any caliber gun, from 2" to 20" can flash fire, so long as it's the main armament. Secondary guns can not flash fire unless they are over 6" in caliber. Many players prefer to use substantially more armour on guns above 6" calibre to avoid this effect. Great Britain has a national penalty that gives them increased vulnerability to flash fires as of the 1900 start date, to reflect their very high battlecruiser losses at Jutland (among others), so this is especially relevant for British designs.

Every turret flash fire reduces the subsequent risks of flash fires, to represents improvements in safety procedures in light of disastrous explosions. Note this only applies to turret flash fires and does not affect magazine explosions from penetrated magazines.

There is also a less devastating flash fire event, in which rather than destroying the ship outright, one turret flash fires, and it spreads to an adjacent turret, destroying both and rendering them both inoperable for the remainder of the battle, but does not destroy the ship.

### Turrets and Casemates

Guns may be mounted in single-gun casemates or turrets of 1-4 guns. Casemates have limited fields of fire, and cannot be used with dual-purpose guns. They are also affected more strongly by rough weather, especially on ships with low freeboard. However, armour on casemates helps increase the effective armour of a ship's belt. Casemates are also somewhat lighter than single-gun turrets, and they do not consume topside space, allowing a ship to mount more light and medium anti-aircraft guns.

Turrets have wider fields of fire than casemates. Turrets may mount dual-purpose guns, increased elevation, and cross-deck firing, with appropriate technology and layout. Turrets can also mount multiple guns at once, and receive weight savings when they do so. However, if a turret is disabled or destroyed, all guns in that turret are also knocked out. Turrets must also have armoured roofs if the turret is to be armoured, which can increase weight.

In 1900, only casemates, single turrets, and dual turrets are available, and double turrets are only allowed on some ship classes. Triple and quadruple turrets are unlocked by technology, and even after they are unlocked they are less reliable than smaller turrets until the Improved Triple and Improved Quadruple technologies are unlocked. However, they allow more firepower in a more compact area, and help save weight. As well, turrets larger than double may never be mounted in wing positions.

### Main, Secondary, and Tertiary Guns

Each ship class may have three different gun calibres - the main battery, secondary guns, and tertiary guns.

The **main battery** can be customized significantly, with the player choosing how many guns to mount in which positions. The main battery also affects many things about the ship - it often helps determine the ship's class, and it is the only battery considered for whether a ship receives the weight reduction from all-forward armament, for example. Ammunition load per gun may also be customized, though every main-battery gun on a given ship gets the same ammunition load. Main battery guns may benefit from fire control bonuses from the beginning of the game. Main guns are typically armoured (except for ship classes which disallow armour, such as destroyers). Main caliber guns may range from 2-20 inches.

**Secondary guns** may be used if main guns are mounted, and must be a smaller calibre than the main guns. Secondary guns may not be customized as aggressively as main guns - their positions are automatically chosen by the ship designer, and they are always symmetrical around the ship's centreline. (Note that not all secondary guns are always illustrated, especially if there are 2+ guns per turret. The remainder are placed on the ship's centreline.) Secondary guns may be armoured, and they may use directors once the appropriate technology has been unlocked. Secondary guns may range from 2-16 inches.

**Tertiary guns** may be used if secondary guns are mounted, and must be a smaller calibre than the secondary guns. Tertiary guns are not illustrated on the ship, and are again auto-placed symmetrically. Tertiary guns may not be armoured, and may not use directors. The mounting of tertiary guns does not affect their mass, unlike main and secondary guns. However, it does affect them for the purpose of making guns DP - casemates and triple/quad turrets cannot mount DP tertiary guns. Tertiary guns may range from 2-6 inches.

### Gun Enhancements

Guns may be enhanced with certain additional features as technology advances.

**Dual-Purpose** guns may fire on enemy aircraft - they are considered heavy anti-aircraft in a ship's statistics. Only guns of 3-6" may be true DP guns, and they must be mounted in single turrets or (when tech permits) double turrets. Mixing DP calibres is penalized, with all calibres but the largest receiving a 60% penalty to their effectiveness, due to the difficulty in determining which shells are doing what. Generally, 4" and 5" are the most effective calibres for anti-aircraft purposes. DP guns should be given a large amount of HE shells by the nation's doctrine, as HE shells are what is fired at aircraft. Dual-purpose guns weigh more than standard guns, but due to their increased flexibility, they are popular on ships designed after roughly WW1.

**Auto-Loading** guns have improved rate of fire compared to their regular counterparts. ROF is increased 10% in most circumstances, and 30% when the gun is on target and making hits. Auto-loaders are available for guns of 3"-8", and are popular for post-WW2 era designs. Again, there is a weight penalty for auto-loading guns.

**Increased Elevation** on guns increase the range of the guns. This has no weight cost, but requires a refit to retroactively apply to older ships..

**Cross-Deck Firing** may be used for guns mounted in wing positions. It improves their firing arc, giving them a narrow arc on the opposite side of the ship from where they are mounted - for example, a port-mounted turret may fire to starboard. It has a minor weight penalty, note this is not applied to the turret's weight.

## Statistics

Gun statistics for various calibers are given below. These values are all raw numbers, and the units are not specified. Many multipliers are applied by the game engine that will not be included below. As a result, these numbers can be used to compare different guns to each other (assuming the same tech and quality levels), but they should not be expected to match any values given in-game.

### Range/Rate of Fire/Damage

Gun statistics as of v1.05b, taken from this thread and this thread. Gun weight derived from ship designer in v1.20 using a single-mount unarmored A turret. Minimum ship mass refers to the size a ship should be to avoid a 20% rate of fire penalty for being over-gunned. Damage is based on shell mass to the power of 2/3, per a Dev post in the linked threads.

### Base penetration of vertical armor

Penetration values can vary up to 20% to simulate the presence of weak spots in the armor.