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A ship refers both to a piece of equipment produced by dockyards and, once launched and manned, a member of a task force that can participate in naval warfare.


A ship belongs to a ship class. A ship class is based on a hull model which, combined with the modules it carries, determines its stats. Each type and level of hull allows different modules to be fitted to the ship.

Without Man the GunsMan the Guns pre-configured ship classes are directly researched. It is possible to create variants of those classes that improve certain aspects without affecting the module layout.

TODO: list of non-MtG ship designs

Convoys and carriers have a hidden attribute offensive_weapons = no causing them to behave differently in naval combat.

Ship designer

With Man the GunsMan the Guns individual ship hulls and modules get researched, which need to be combined using naval experience to create a ship class.

TODO: list of ship components




Depending on the designation as capital ship and the combination of hull and armor, a ship falls into one of the following categories. The category determines where a ship gets placed in naval combat and influences that targeting decision of other ships and air planes.


Carriers (CV) can launch naval strikes on the enemy from a distance and enable air missions in their range but are very vulnerable when not properly protected.

Capital ships

Capital ships provide the main direct firepower of a task force and are heavily armored but vulnerable to torpedoes and naval strikes (which ignore armor).

  • heavy cruiser (CA): The most lightly armored capital ships, but usually cheaper and faster too. They provide cost-efficient fire power against lighter ships
  • battlecruiser (BC): More heavily armored cruiser that counters lighter enemy cruisers.
  • battleship (BB/SHBB): The largest, most expensive, most heavily armored capital ships.


Screens are cheaper, lightly armored surface ships. They can efficiently patrol sea regions and escort convoys due to their high numbers. In battle they protect capital ships from torpedo and air attacks.

  • destroyer (DD): Being the cheapest (both in production and fuel consumption), most lightly armored screening ships, destroyers are well suited to make up the bulk of patrol and escort forces in shallower sea regions and any other tasks that don't require raw direct firepower. Their high speed makes heavy gun fire ineffective against them and equipped with torpedoes and depth charges they can be deadly against capital ships and submarines respectively.
  • light cruiser (CL): More heavily armored and with better range than destroyers, light cruisers are better suited for the open sea. Their armor and better armament makes them effective against destroyers, while they can still perform essentially the same tasks, albeit at a higher production and fuel cost.


Cheap, slow, and stealthy, submarines (SS) excel at sneak attacks with their torpedoes on unescorted convoys and unscreened capital ships. If the enemy doesn't have the proper detection technology, submarines can operate for a long time in waters that are enemy-controlled on the surface and efficiently bind up enemy forces due to their very low production cost.



The supremacy value of a ship is 100 + <manpower> * 0.05 + <build cost> * 0.005. For example the supremacy of an early submarine is about 115 and a battleship has about 500.


Pride of the fleet

Combat history


Each class of ship has numerical attributes referred to as stats. The stats of individual ships only have a direct influence in battle and accidents, otherwise they usually contribute to the averaged stats of the task force they belong to.

The stats of a particular ship are based on its equipment (i.e. the ship class).

Base stats

  • max speed: the speed of the slowest ship in a task force is used as the task force's speed when moving across the map. In battle the speed decreases the ship's hit profile and allows it to disengage faster. The speed of a ship can not be reduced below 1 knot. Lack of fuel reduces the speed by up to -75%.
  • max range: Determines how far from friendly ports the ship's task force can move and operate. Lack of fuel reduces the max range by up to -75%.
  • (max) organization: Indicates a ship's maximum combat readiness. A ship with low maximum organization quickly loses combat effectiveness more quickly (lower chance to land hits in combat). Affected by the modifiers Navy Organization (additive) and Navy Organization (multiplicative). During exercises maximum organization is reduced to 20% of the normal value.
  • deck size: How many planes a carrier can fit on board.
  • (max) HP: Represents how much physical damage the fully repaired ship can take before it is destroyed.
  • reliability: Makes the ship more resistant to critical hits and accidents.
  • supply use: The supply use of the ship.

Combat stats

  • light attack: Damage done by light guns. Light guns are better at targeting smaller ships. Lack of fuel reduces light attack by up to -50%.
  • light piercing: Armor piercing of the light guns.
  • torpedo attack: Damage done by torpedoes. Torpedoes are better at targeting bigger ships. Lack of fuel reduces torpedo attack by up to -50%.
  • depth charges: Damage done by depth charges, used against submarines. Lack of fuel reduces depth charge attack by up to -50%.
  • heavy attack: Damage done by the heavy guns. Heavy guns are better at targeting bigger ships. Lack of fuel reduces heavy attack by up to -50%.
  • heavy piercing: Armor piercing of the heavy guns.
  • armor: Having armor that is higher than the enemy's piercing reduces damage taken.
  • anti-air: How much firepower the ship carries for shooting down enemy planes.

Miscellaneous stats

  • fuel usage: How much fuel this unit uses while it is operating. Ships consume fuel while moving, on active missions, or during training.
  • surface visibility: How easy a surface ship is to find and hit.
  • surface detection: Ability to detect surface vessels.
  • sub visibility: How easy a submarine ship is to find and hit.
  • sub detection: Ability to detect submarines.





(type: integer) Number of convoys sunk by this ship.


(type: number (3 decimal places)) Current organization.


(type: tag, default: the country controlling the ship's task force) Country that built this ship.


(type: equipment variant pool) A list of equipment variants and their counts that this ship uses. This will usually be just a single ship. If no equipment is provided, the country's latest equipment variant matching the definition is used.


Air wings stationed on a carrier.


(type: string) Name of the unit definition this ship uses (see /Hearts of Iron IV/common/units).


(type: number (3 decimal places), default: 0) Current experience level. In OOBs use start_experience_factor instead.


(type: string) The ships name.


(type: number (3 decimal places)) Current strength/HP.


(type: integer) How much manpower the ship needs.


History entry for a ship that has been sunk. Can appear multiple times.


(type: integer) How much manpower the ship currently has.


Definition of critical damage instances the ship has.


(type: integer) Index in the name list to use.


(type: integer)


(type: integer)


(type: name group member) A more advanced way to set the ship's name based on name groups.


No effect.


(type: reference) Reference to refit production line.



If present, the ship is marked as pride of the fleet. The value does not matter but yes is used as a convention.


(type: number (3 decimal places), default: 0) Experience level to set when creating the ship.