Logistics

From Hearts of Iron 4 Wiki
Revision as of 02:28, 3 September 2016 by Potski (talk | contribs) (Expanded parts, still needs work)
Jump to navigation Jump to search

Logistics consists of getting supply and equipment where it needs to be.

Supply Consumption

Supply Use Statistic and accompanying tooltip

Supply Consumption is a general term for the amount of supplies and equipment being expended each day by your military. The supply map mode helps you determine how much supply is being consumed/produced in a given Supply Area, and the Logistics Window will help you determine how much equipment is being utilized throughout your entire nation.

Supply Use

Supply Use is the daily rate at which a unit consumes band-aids, bullets, and beans (aka, Supply).

Each division has a base level of Supply Use, which is a sum of the Supply Use of the battalions and support companies in the division's template, which is then modified by the percentage of the current manpower in the division. Finally, the level of activity of the division gives a modifier:

  • When inactive: -5%
  • When moving or in combat: +50%

Air wings and ships also have a Supply Use. These are not affected by manpower, nor activity.

Equipment Usage

In addition to consuming supplies, a unit will also lose equipment. This can happen from attrition and accidents or combat. The equipment has to be replaced through your logistics system.

Supply Area

The world map is split into supply areas covering land, which consist of, usually, a couple states. Each area has its own supported supply limit on how many supplies can be delivered to the units within that area. If the requirements of the units in the area exceeds the supported supply limit, then the army takes attrition and gets combat penalties. The supported supply limit is calculated by adding the following two factors.

Local supply

Local supply (outdated/probably shows infra levels not supported supply limits?)

The sum of the following:

  • A base value 1-16 for the specific supply area.
  • Each named city province that has Victory Points in the supply area adds:
    • 1-15 VPs: +1
    • 16-25 VPs: +2
    • 26-35 VPs: +3
    • 36-45 VPs: +4
    • 46-55 VPs: +5

Incoming supply

Supplies can flow from your capital to the destination overland, or overland -> overseas by convoy -> overland. The supply system prefers overland routes, and determines the most efficient supply areas to go through to get there. You cannot control the route it takes. If the overland route would be longer than 15 supply areas, or it is impossible to reach the destination supply area because it is on a different landmass to the capital, then the system will use a supply route which includes an overseas journey by convoy.

There cannot be two overseas journeys involved, so the supply system cannot by-pass blocked straits.

If there is no valid route overseas, because of blocked straits, or none overland because the units are contained in a pocket surrounded by the enemy, then the units will receive no incoming supply. They also will not be able to receive any equipment or manpower replacements, reinforcements or upgrades from the logistics system.

In determining the route of supply convoys overseas, the system can use any two naval bases which you control, or which are controlled by members of your faction. It will favour naval bases which have higher levels, if there are more than one available.

Incoming supply is equal to the bottleneck (lowest value) on the best path from the capital including both the end supply area and the capital. Supply areas are connected with supply values as follows:

  • Overland: Supply areas with a land adjacency. The value is the sum of:
  • 0.5 times the square of the average infrastructure in the sending supply area. Capitals do not receive this factor.
  • 2 times the square of the average infrastructure in the receiving supply area. Note that capitals get this value as "local" supply.
  • By convoy overseas: Supply areas with a convoy route connection. The maximum supply throughput is the lower of 3 times the levels of each of the naval bases in the sending and receiving supply areas. But this is modified by the efficiency of the convoy route.

Supply effects

Units require supply to function at maximum capacity. If the units in a supply area consume more supply than is supported, they will start suffering penalties.

Grace period

The grace period is how long a unit can go while being cut off from supplies before it actually suffers from the lack of supply penalties. The default length of this period is 72 hours, while the Pocket DefensePocket Defense doctrine increases this by 48 hours.

Out of supply penalties

If a unit is below maximum supply, it suffers up to the following penalties:

  • 30% attrition
  • -80% organization
  • -30% recovery rate
  • -20% combat modifier

These penalties are multiplied by 1 minus the supply fraction. The penalties ramp up linearly from zero to this amount over 30 days.

Logistics UI

There are two parts to the logistics UI: the supply map, and the logistics screen. The map, accessible through the shortcut F4, shows supply areas and the supported supply limit of all of the supply areas that are in your nation, are on the coast, or border your nation. The logistics screen, accessible via the shortcut I, shows the stockpiles of various Army, Air Force, and Navy equipment that are currently available in your nation, the deficit or surplus of those supplies, and so on.

Supply Map

Main article: supply map

The supply map is one of the game's map modes, which shows the supply areas of the world and ocean going trade routes your nation has.

Logistics Window

Main article: logistics window

The logistics window is one of the main user interface screens which shows information about the country's resources and equipment.

Convoys

Convoy
1Steel 1Oil
Convoy.png


Convoys used for internation trade of goods and resources. Also used to ferry troops around and for performing naval invasions.

Convoys are only used if a trade route is engaged with a nation that cannot be accessed by a direct land route [It appears that land routes are only on the same continent or neighbors?] Thus, if a nation is landlocked, they may not use convoys nor engage in trade with a non-neighboring country. They are made from the production window and may be built to a set number of convoys or indefinitely just like any other naval unit. However, unlike all other naval units, they may not be deployed and are automatically stockpiled. This cannot be changed.

Trading

Troop Transport and Naval Invasions

In the Naval Units technology screen, at the bottom, there is a line of technologies named Transports. These increase the naval invasion capacity (How many troops can be used to invade from under one command and one port at a time), reduce the naval invasion penalties so that fighting may be more effective, decrease the preparation time, increase the invasion speed, and reduce troop convoy requirements. A naval invasion, once planned, will consume convoys from the stockpile and if there are none in the stockpile, will wait for more to be produced. In addition, the convoys will be returned to the stockpile after an invasion, unless if they are destroyed in transit, in which case both the convoys and the troops will be lost. Selecting a group of divisions under a command will have a picture of a ship sailing next to the Strategic Redeployment order and will tell the total weight of the divisions, or how many convoys are needed to transport the divisions.