Hearts of Iron 4 Navy

Of the three aspects of warfare in Hearts of Iron 4, the navy is easily the least understood and least used. The production cost associated with creating ships is significant, making a strong navy a considerable investment. This does come with some benefits, however, namely the ability to disrupt convoys, protect your own convoys, and conduct naval invasions. To make the most of your fleet, it’s vital to understand your options when it comes to naval warfare.

Naval Organization and Commanders

Your navy in Hearts of Iron is organized into theatres, fleets, and task forces. Theatres will contain your fleets, which hold your task forces. Task forces are the smallest unit you can control, but you will frequently issue fleet-wide commands rather than give commands at the task force level.

Each fleet can be assigned a single admiral from the country’s officer corps. Admirals can provide some crucial bonuses that can change the tide of a war, including direct bonuses to attack, defense, maneuvering, and coordination.

An admiral can control a maximum of 10 task forces simultaneously before the benefits they provide start to deteriorate..

Types of Ships

There are a variety of ships in Hearts of Iron 4, and you’ll have to use a combination of all of them to be successful. They can be grouped into 3 categories:

• Capital ships
• Screen ships
• Submarines

By using the best ship designs, you’ll be able to maximize the usefulness of each ship in your fleet.

Capital Ships

The largest — and most expensive — boats in your fleets and task forces will be the capital ships. They are the main force on surface battles, but can be overwhelmed if not properly protected by screen ships. Considering how long it takes to build these, protecting them should be your number one priority.

• Super-heavy battleships and battleships are the strongest ships, with battleships being considerably more common due to the absurd cost of the super-heavies.
• Battlecruisers are faster but less armored and have less weaponry than battleships.
• Heavy cruisers have the lightest capital ship armor so are vulnerable against bigger ships but are easier to produce.
• Aircraft Carriers hold uniquely built aircraft and serve as a mobile airbase.

Each type of capital ship has its own role, depending on your country’s situation. You should choose which capital ship to build based on the task force compositions that work for you.

Screen Ships and Submarines

The smaller, less powerful ships that surround capital ships are screens. They include light cruisers and destroyers, and their main goal is to protect larger ships from torpedoes. Submarines are in a similar tier, but perform different roles.

• Light cruisers pack a bit more of a punch but are expensive.
• Destroyers are cheaper, allowing you to build more to protect each capital ship.
• Submarines are stealthy, underwater vessels that are great at raiding convoys and laying mines. They are typically not very effective at head to head combat.

Naval Missions and Strategies

You can control your fleets and task forces by assigning them a mission— the naval mission you assign will determine their role and how they operate. To assign a mission, you’ll have to choose a minimum of one sea region, but multiple can be chosen. All missions require a minimum of one task force per sea region covered. A total of seven missions are available for your fleet to embark on. Patrol and Strike Force are the main missions you’ll use in campaigns, and they focus on controlling sea regions.

• Patrol has your ships actively sailing around an area to engage any spotted enemies.
• Strike Force keeps your ships safely in port until an enemy enters a nearby sea zone, at which point your ships will deploy to intercept them. This conserves fuel and reduces attrition compared to constant patrolling.

Convoy Raiding and Convoy Escort deal with convoy supply lines which are critical to every country, but especially so for island nations like Japan and the UK. There is also a specific mission type for supporting naval invasions.

• Assign a Convoy Raiding mission to a region to destroy enemy convoys and hurt their supply of resources.
• Create a Convoy Escort mission to protect your own convoys, especially in heavily contested regions.
• Naval Invasion Support Missions are used to protect the convoys carrying your troops and perform shore bombardments as they land.

Finally, Minelaying and Minesweeping missions, as you might guess, deal with underwater mines. These missions will only be available if the Man the Guns DLC is activated and your ships have the appropriate equipment. You can add a minesweeping or minelaying module to a ship through the ship designer.

• Minelaying missions will add underwater mines to the specified region(s) until the maximum amount of 1000 is reached.
• Minesweeping missions will remove underwater mines from the specified region(s) until all mines are removed.

Naval Warfare Mechanics

Naval combat in Hearts of Iron follows a structured system, making it easy to predict how your fleet will work in battle. Ships will arrange themselves into 3 distinct groups, based on the ship types described above.

Screening ships will be in the frontline to shield everything behind them from torpedoes. For full protection, you should have a minimum of 3 screening ships per capital ship. Directly behind the screening line are your capital ships, which will do the most damage. Finally, any carriers will occupy the back line. To adequately protect aircraft carriers, you’ll need 1 capital ship per carrier.

Combat itself occurs hourly, with ships engaging targets based on their armament. Light guns can only strike the closest formation, while heavy guns can reach deeper into enemy lines. Torpedoes present a unique threat, as they can potentially bypass screens entirely depending on the enemy’s screening efficiency. Depth charges serve as your only weapon against submarines, but they only work once the submarine has been detected.

With a strong understanding of the navy and naval warfare in Hearts of Iron, you’ll be ready to conquer the seas in no time. Do you use the navy much in your campaigns? Let us know in the comments below!