|Please help improve this article or section by expanding it with: a section on convoys, and the Logistics UI.|
Logistics consists of getting men (replacements), supplies and equipment where they need to be in order to support the fighting forces. As these are needed for an army to fight efficiently, and supply in particular is necessary for troops to just survive, logistics is of vital importance in war.
Supply Consumption is a general term for the amount of supplies and equipment being expended each day by the military. The supply map mode helps to understand how much supply is being consumed/produced in a given Supply Area, and the Logistics Window will indicate how much equipment is being utilized throughout the entire nation.
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.
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 the logistics system.
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 exceed 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.
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
Supplies can flow from the 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. It is not possible to 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.
It is important to know that 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 under friendly control, meaning they are controlled by the country itself or members of the faction a country is part of. 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, meaning that low or damaged infrastructure can cripple front-line forces through inadequate logistics support. 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.
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 in battles, in addition to the penalties of lacking manpower and equipment.
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 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.
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 the nation, occupied by it, on the coast, or bordering the nation. The logistics screen, accessible via the shortcut I, shows the nation's stockpiles of various Army, Air Force, and Navy equipment that are currently available, the deficit or surplus of those supplies, and so on.
- Main article: supply map
The supply map is one of the game's map modes, which shows the supply areas of the world and the player's ocean going trade routes.
- 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 are only used if a trade route is engaged with a nation that cannot be accessed by a direct land route within a certain range. Thus, if a nation is landlocked, they may not use convoys. Convoys are created by dockyards in 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 as a convoy pool. This cannot be changed. Convoys are automatically drawn from this pool as needed for trade, supply, lend-lease, and transportation of ground troops (including invasions).
- Main article: Trade
Any country may be lacking one or more resources at any point in the game and may turn to trading to supplement them.
Note: It is not possible to conduct trade between two warring nations or if having the Closed Economy Law.
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 use convoys drawn from the stockpile. If there are none in the stockpile, the invasion will wait for more to be produced or released back to the stockpile from other uses. Transport convoys will be returned to the stockpile after an invasion, unless they are destroyed in transit, in which case both the convoys and any troops aboard 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. Please note that transports are not specifically accumulated for a specific invasion. Thus, it is quite possible to run out of transports before the operation commences. This is particularly true if England has not fallen. Even in 1940 there can be 1000 planes over the Channel and a UK fleet of 64+ ships. This does not include French subs that have survived or the small UK sub fleet which will also focus on the Channel. In a 30 day period it is possible to lose 100+ transports in the English Channel alone.
- a range of 1000 is found in the defines, but the unit is unknown; in-game it means Switzerland just can't reach China)