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Hi, this is the author of VNR, MrPunk. VNR is a naval overhaul mod with a huge amount of new contents and mechanisms, though its core is still similar to vanilla. I bet most people, whether experienced in navy or not, might face a hard time adjusting to a fresh style of naval game. I'm not an expert, but I want to write down this guide with insights during my modding process, in an attempt to relieve players from duplicate learning.

You can play VNR in different ways. Stick to history if you want to do it in a realistic style, or create meta designs to simply be a winner. It's up to you which style to pick, and VNR always offers numerous things for you to achieve that.

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Designer is the basic of VNR and the most important components you deal with. To design a ship, you need to know about your requirements and more. A good navy does not always equal to the United States Navy in real life, but it should fit in your overall strategy and geopolitical environment. Fortunately, VNR has a wide range of modules to help you customize your fleet. To begin with, I'd like to bring up the six dimensions of ship designs.


Firepower

Firepower in HOI4 is split into 3 types of attacks, light, heavy and torpedo.

Light attack is provided by batteries on destroyers and cruisers, and secondary batteries on capital ships. Heavy attack is the damage done by heavy batteries on battleships or battlecruisers, and medium guns on heavy cruisers by a very small amount. While damage caused by guns is affected by armor of target which their ratio leads to very different damage and critical chance, torpedo simply ignores armor and can cause great damage and score more critical hits, but it's fired more slowly and suffers a great penalty on hit chance when screen efficiency is good. Given that enemy's screen efficiency is one vital factor in the equation, swiftly eliminating its screen ships paves the way to a grand victory because low screen efficiency of the other side will make dynamics at sea more favorable to your side.

A conclusion can be drawn here. Light gun is very efficient against light ships, with the other side's screen efficiency totally crushed, your fleet will have an upper hand in hitting and evasion. Heavy gun can do more damage to heavy ships due to its heavy armor piercing effects, though it's not common to see battleships sunk by it. Torpedo have a higher critical chance against heavy ships and carriers which often deals triple or even quadruple damages, but its setbacks are long loading time and low hit chance.

Carrier, on the other hand, is very different from all the firepowers mentioned above. Its damage relies on your air variants and sortie efficiency, and is only affected by weather, anti-air and night.

Protection

The protection of ships varies on different hulls. For example, destroyer has close to zero protection, cruiser has armor plates, while battleship possesses armor, scheme and torpedo defense systems.

When HP gets reduced to 0, the ship will be sunk. Typically, the two ways to avoid it will be enhancing your ship in terms of HP and armor strength. Having more HP brings obvious benefits that the ship can take more damage before sunk. Armor improves survivability with a different approach to reduce damage received each time it's hit. Based on the formula listed in intro panel, if armor piercing of a gun is lower than half of the armor, its damage is reduced to 20% of its original value. As a result, armor is extremely useful against guns.

Torpedo completely ignores armor and can cause great damage. Even torpedo defense system is not effective enough to save the ship if it gets hit by torpedo. But luckily, with a good escort force, torpedo will have a hard time penetrating the screen line to get your capital ships.

Contrary to most people's impression, anti-air is also a part of protection facing aircrafts and carriers. Good AA provides damage reduction or even evasion when attacked by planes, and it gets more bonus from the overall AA from your fleet, factored to align with the ship's. That means a ship without anti-air gun can also benefit from other ships' AA, but anti-air guns are mandatory if you want to shoot down the plane.

Speed

Besides stacking armor, another way to improve your ship's survivability is to increase its speed. Higher speed helps reduce ship's hit profile which is compared with hit chance of guns to determine whether your ship is hit or not. As an effective measure to evade gun fires, however, speed is useless against planes. In order to get a higher speed, avoid stacking too many guns or armors on a hull. Generally speaking, you'd better make capital ships around 30kn, light ships 35-40kn.

Reliability

The impact of reliability is not superficial, but it determines how likely the ship may suffer a critical hit or damaged in accidents. Many immature or complex modules such as quad guns and missiles will cause loss of reliability, making the ship very vulnerable in combat and training, just like the Swedish warship Wasa. In my opinion, low reliability is somewhat tolerable on platforms with higher HP, but it's definitely not recommended on light hulls.

Detection

Detection, or recon, is a very important factor to gain initiativeness in naval combat. It is divided into surface detection and sub detection, with influence on spotting enemy fleet or submarines. Greater detection is always good, but it's also expensive, so only vanguard fleet is usually composed of fast and dedicated recon ships.

Cost

Unless you are playing as US or UK, building a large fleet takes too much time and IC, and it may hamper your army production. This is especially true for countries like Germany or Soviet Union which requires army focus more than anyone else. As a result, keeping the cost of shipbuilding programs under control can make the whole experience of your game smoother.


If you can fully understand the six dimensions, now it's time to design your first ship!

Carrier

Carrier serves as the main source of damage in battle, and it's heavily relied on its aircrafts. The most important thing about it is the capacity, which requires you to mount as many hangars as possible. However, having too many hangars will certainly degrade speed and other metrics, especially that organisation and HP will impact sortie efficiency. Thus, you should keep the degradation under control.

Heavy Ship

You can't skip heavy ships, such as battleships and battlecruisers, in your fleet. While screen ships escort capital ships, these heavy ships will escort carriers and boost their survivability by drawing aircrafts' attack. It's hard to summarize the key to such ship because it literally needs every aspect to be perfectly balanced. Firepower may not be the keypoint on battleships since their maximum HP is almost immortal compared to guns' heavy attack, but armor and AA are needed to protect itself and other ships, especially carriers. In that case, a historical battleship is more than sufficient to be included in a strike taskforce.

On the other hand, battlecruiser is not a good option despite its advantage of speed. Its chance to receive critical hit is higher than battleship, which battleship with high speed engine is already fast enough.

As for super heavy battleships, you can mount one gun on it to fully utilize its high HP, but normally it's not recommended.

Cruiser

Unlike vanilla, heavy cruiser and light cruiser in VNR are not defined by its gun caliber but by role. Yet there are still differences between cruiser guns. Light medium guns are similar to their origins, but medium guns have bonus on HP and armor to simulate a linear relation between survivability and tonnage. In VNR, heavy cruiser plays the role of cruiser killer instead of being useless in capital line, it's more flexible and can perform actions in both capital line and screen line based on the role you give it. As mentioned above, cruisers use light attack to eliminate screen ships and crush enemy's screen efficiency, creating a more favorable situation for your fleet to fire on the enemy. To achieve that, you need to pursue a fast and light-gun-centric design in order to keep up with destroyers and wipe out enemy's screen line as fast as you can.

Cruiser is not only used for attack, but also some supporting jobs, such as scouting, and sometimes it can be a luxurious option for anti-submarine and mine warfare. That's where the role system gonna help you to fully dig out all its potentials. Radar picket cruiser is perfect for spotting enemy fleet. Colonial cruiser is cheaper, good supplement to colonial empire like UK and also a second best choice for minor countries. Then you have large cruiser and missile cruiser if there are sufficient IC power within your nation. The list goes on, but one thing for sure is that cruiser offers the most possibilities in all kinds of ships.

Destroyer

Destroyer is weak at the first glance, but it has the best speed and visibility in the game. Since destroyer's gun is almost useless against any ships but itself, torpedo is often used as the main weapon of destroyer, making destroyer heavily depending on the diminishment of your enemy's screen efficiency. Besides, destroyers also shoulder the most important mission in the fleet, which is to maintain screen efficiency by their numbers. Therefore, cost should always be the top priority when designing a destroyer, and there are a series of roles to achieve that.

Typically, the generic destroyer role can handle most scenarios. Escort destroyer is cheaper and expert at anti-submarine, and frigate can reduce the cost even more with numerous degradations in other aspects. Of course, you can also try to go another way to improve quality of your destroyer. Roles like destroyer leader and super destroyer can both enhance its performance in terms of firepower and protection at the cost of a sharp increase in IC. Destroyer leader may look redundant in the list, you are correct, that's also the reason why this type of ships was eventually outdated in history.

Submarine

Subs are greatly nerfed compared to vanilla in terms of competing with a proper fleet, but they are still lethal towards convoys. There isn't much choice for each slot on submarine like other ships, and that makes the design of submarines quite linear and easier since all you have to do is updating it with new hulls or new modules.

AI in VNR has been enhanced to carry more depth charges and sonars, which is a major challenge to sub-centric games. As a result, you should try to lower your sub visibility as much as possible. Mount every useful module, including snorkel and pressure hull, on your sub and keep them updated to the latest.


Special hulls are ships that can't be simply represented by generic ship hulls. They are made for flavor and immersion. Using them does not always give you a good result in naval battle.

Battlecarrier

Battlecarrier is a hybrid ship with features from both battleship and carrier, you can make one by putting conversion deck on rear slots of the heavy hull. Although it has heavy guns, battlecarrier is considered as carrier and is in the carrier line, and it's restricted by the max carrier limit. Furthermore, battlecarrier can't get any bonus from doctrines, and its high conversion cost also blocks the possibility to build the fleet around it.

Super Heavy Battleship

In fact, super heavy battleship has no fundamental difference from ordinary battleships. It's just larger and more expensive with dedicated armor and engines.

Escort Carrier

A cheap but very weak carrier. Escort carrier is unlocked around 1940-1941 in the techtree, it's basically a toy for major powers as the carrier count limit largely restricts its usage scenario, but it's still a perfect choice for anti-submarine missions in secondary theaters.

Super Carrier

Just like Essex or Midway post-refit, super carrier is a weapon with no shortcoming. By combining with modern carrier modules such as large armored hangar, steamed catapult and side lifts, a super carrier can possess a capacity of 130-150 planes. Except for its incredible cost, super carrier is the best type of carrier in the mod.

Panzerschiff

Panzerschiff in VNR or revived armored cruiser in KRNR, is basically a cruiser with heavy guns, though there is a limit set to prevent super heavy guns being installed on it. Just like the real armored ship in history, it has some advantages in one-on-one combat against cruisers, such as better guns and armor, making it an intermediate option between battlecruiser and heavy cruiser. The problem is, panzerschiff is stuck in the middle, so it can't fully cover either's job.

Auxiliary Ship

The max range of the fleet is calculated by average range of all ships within, so mathematically speaking you can boost it by adding long-range ships to your fleet. However, if you know maths very well, you may notice once the average surpass a certain value, it will bring the increase rate to a stagnation, so it's unwise to put too many auxiliary ships together because the range bonus is reaching the upper limit.

To keep it away from the frontline, auxiliary ship is considered as capital ship, which means it can provide escort efficiency for your carrier just like battleship does. It's weak without doubt, but really really cheap.

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Techtree is the soul of VNR and also the most interesting part of the game. Compared to base game, the naval techtree has been expanded in width and depth, from bonuses to modules. From the first glance, it may look complicated for people who love short and condensed techtree. It is large but you don't necessarily have to research all of them, and I will try to make your decision easier. Note that not all techs are worthy, you have to choose wisely and try not to overwhelm yourself.


Destroyer Branch

Destroyer is the fundation of any navies, so there is no reason that you should skip this part of the tree, unless you don't want to play navy at all. As I mentioned in designing section, cost is the key element of destroyer variants, so any tech that lowers IC cost of a ship is certainly a must. The research on destroyer should be centered around the job you give them in your fleet. Anti-submarine is one of the most common tasks handled by destroyer, making depth charge and sonar technologies become the theme of this branch. Typically, that's all you need to have to make a decent destroyer. When I say "decent", it stands for "a ship that works under most circumstances regardless of which country you are playing", but there are exceptions that you will be against different enemies.

Cruiser Branch

Cruiser can make incredible damage on light ships in the battle when it gets into close combat stage. Therefore, if you want to build a nice surface fleet, don't hesitate to give your cruiser the best guns and armors. Although you have many options in cruiser's tree, the process becomes easier that you only have to choose those improve it in terms of things you really need, including firepower, speed and armor.

Heavy Armor Branch

This branch is composed of battleship armor scheme and armor processing technologies. The necessity depends on whether you are going to include heavy ships in your fleet and when you want to exclude them. If heavy ships still hold a place in your fleet, you should update these techs to the latest whenever there's a chance, otherwise just leave it alone.

Battleship Branch

Battleship branch is actually quite flexible because you can drop it from anywhere if it's no longer needed in your fleet. But if you want a good cold war era experience, at least research hulls to gain access to cold war fire-control/nuclear-fleet technologies. Back to the base tree, battleship techs prior to the 1930s are very useful despite not being mandatory. Its sub techs during the early 1940s are not recommended for their crummy bonus unless it's out of roleplay. After all, not many people will need excellent battleships but just-okay ones.

Carrier Branch

I can't stress more about the dominating power of carrier in reality and mod. Except for some early sub techs of carrier which only apply little bonus, most carrier techs are extremely useful and will definitely give you an upper hand in the battle. My suggestion is to skip techs before 1932, and get all of them after that.

Submarine Branch

Submarine is useless against anything but convoys because of AI's ASW improvements. Submarine research should be centered around lowering visibility and improving torpedo attack, other techs remain optional no matter what bonus they offer.


Gun Branch

You need guns everywhere, so there is basically no reason to skip this branch. Except for super heavy guns and rocket artillery, get all techs to the latest if you want to have a decent fleet.

Torpedo Branch

Torpedo techs are needed by both submarines and torpedo ships, and overall torpedo weapons are nerfed in accuracy but buffed in damage. Keep it up to date if your fleet is heavily relied on torpedo.

Auxiliary Branch

The auxiliary branch is split into three sub-branches, port facilities, auxiliary ships and fuel silos. Basically designed for immersion, you can just skip the whole branch without need to worry about missing important bonus or modules. Of course, if you want to experience this part of the mod, there are some useful techs.

The branch of port facilities aims at accelerating building and repairing speed of naval infrastructure such as shipyard and naval base, but I won't recommended you to finish this line due to poor bonus.

Auxiliary ship branch is centered around the debate over "range or speed". Speed branch is relatively better since it's one of the six dimensions of ship designs and it offers some exclusive modules like raider cruiser.

As for fuel branch, its research cost is insignificant with little bonus, making it an irrelevant factor in your game.

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Speaking of the mechanism of naval combat, it's mostly untouched in this mod, so your experience from vanilla still applies here. If you are not familiar with navy, I'd recommend you to read naval sections of HOI4 official wiki which owns a lot of details of basic concepts and advanced formulas of naval combat. [HOI4 wiki](https://hoi4.paradoxwikis.com/Naval_battle)

VNR modifies some parts of naval game to make it more intense and realistic, and the following introduction will only include things changed from vanilla. I will assume you know the basic concepts about naval combat such as screen efficiency, positioning and combat duration, otherwise please refer to the link above first.


The question of fleet composition is based on the concept of screen ratio. This part is identical in VNR and vanilla, which is 1:3. This means a capital ship (heavy ships and carriers) needs at least three screen ships (destroyers and light cruisers, basically anything in the first line of combat) to achieve max screen efficiency. Furthermore, carrier has its own version of screen efficiency that requires not only light ships but also heavy ships. This ratio is 1 to 1.

For example, let's say you have 1 carrier, then you need at least 1 battleship and 6 destroyers or light cruisers (3 for carrier, 3 for battleship) to get 100% efficiency for every ship. However, this is only the lowest standard for a fleet, because you can't avoid losses of ships in the combat. As a result, this ratio has to be expanded to allow some redundancy, like 1:1.5:8.

Besides, make sure your fleet has a min speed over 30kn, this is extremely important to strike forces.


One of the major roles that navy plays in the game is securing sea supremacy to create opportunity for a naval invasion. Compared to vanilla, supremacy factor of different missions are changed. Among them, the factor of convoy raiding is greatly nerfed, meaning even though you have twice the ships in convoy raiding, they will lose in securing sea supremacy against a smaller strike force. The best way to gain control of a piece of waters is by naval invasion support or strike force.

Type of ship also affects efficiency in this area. Decent ships are required in the action, that means you can't secure the sea just with submarines.


To simulate carrier's capability to send over the horizon strikes, the duration of combat is made longer in the mod, but I still kept it under control so that other ships still hold a place in navy. Carrier can send air strikes every 2-3 hour (based on your sortie efficiency) in different squadron size (based on carrier traffic and some other factors). 20 hours after the battle begins, fleet will have a chance to retreat both automatically and manually. Only 22 hours into the battle, battleship got to fire its first salvo, while light ships still have to wait to the 30th hour to fire.


Positioning is typically used to measure how successful the fleet formation is in real life, which is a very important element in the era of ship of line. In the game, it is a factor applied to screen efficiency. Bad positioning may lead to degradation of screen efficiency. In that case, the preferred screen ratio is no longer 1:1:3, you will need more ships to achieve max screen efficiency.

Positioning is affected by several factors including relative size of fleet, speed, detection, etc. To achieve good positioning, make sure to have fast ships with good detection, and avoid maneuvering a super massive fleet around.


Ever since the supply system was added in NSB, navy will also be influenced by port facilities. In vanilla, you rarely feel the consequence of running out of supply in naval combat because ships' supply consumption is too low compared to how much a naval base can provide. To begin with, don't confuse supply consumption with fuel consumption, they are different but will cause similar penalties on your fleet. Fuel is only consumed when your fleet is in action, but supply is a static resource that you can't store.

In the mod, supply consumption of ships are greatly increased, especially on capital ships. This has made strategic islands and frontline engineering corps far more important in simulating the Pacific War. Take US as an example, a large fleet making a sortie from the Midway will definitely suffer heavy attrition during maneuvering and combat. Instead, launching attacks from Hawaii or Australia is a wiser choice.