Hearts of Iron IV – 26th Development Diary – 25th of September 2015

Hello and Welcome to the 26th Development Diary for Hearts of Iron IV. This time we’ll delve into details about the navy.

Ship Research
First of all, we have the naval research tree, where you research upgraded ship types through the years, as well as transport technologies. Of course, everything from submarines to carriers is researched here.

As we mentioned in the 8th development diary, the experience you gain from naval combats can be used to customise variants of various ships, so if you want to increase the guns on your Schlachtschiff H44, then that is possible.

Naval Doctrines
Secondly, we have the naval doctrines. There are three separate doctrine trees, and you can only have one researched at a time.

Fleet in Being
A strong fleet focused around battleships means that we are a force to be reckoned with when deployed at sea. This is the doctrine used by Italy, France & Great Britain.

Trade Interdiction
Against a stronger naval opponent we can focus on tying up their fleet and destroying supply lines to starve their war machine. This is the doctrine used by Germany.

Base Strike
With a strong focus on carriers and their support no enemy will be outside our reach. Neither at land or at sea. This is the doctrine used by USA & Japan.


Naval Missions
Dev Diary 15 covered this, but I’ll just repeat the details about the mission system here again. Now that Invasion is no longer a naval mission, but a battleplanner command, I’ll iterate the four special missions for navies again.

Patrol – This will spread out the fleet to increase chances of catching hostile fleets, but it is a high risk of the fleet not all being present for an engagement. This is something you’d use to catch a single german battleship trying to create havoc.

Search & Destroy – This does not spread out the fleet over the region, keeping it intact to be an efficient fighting group when engaging an hostile fleet. Main battlefleet trying to catch another fleet.

Convoy Raiding – Will attempt avoid engagements with other fleets, and just focus on sinking enemy convoys.

Convoy Escort – Will not engage hostile fleets, but will be very likely to be protecting convoys in the region when attacked.

Automatic Repairs
With a mission system, you need some sort of automation of fleet repairs. There is now a system where you can set fleets on settings on WHEN to return to port, ie, after how heavy damage from never to “mild”. You can also give direct order to go to port and repair and automatically go back when needed. There is also a final option, that the fleet is allowed to split off damaged ships that can be sent to repairs when the rest of the fleet continues its mission.


Next week we’ll take a look at Italy.