SharonC -> WarPlan Dev Diary 5: Supply system (8/5/2019 9:12:33 AM)
There were many variations I went through in trying to determine the best supply system for the game. I thought about doing supply as a board game which is basically a black and white system, you are in supply or you are not. But that didn’t address realism problems as well as I liked. I thought about a complex robust system of supply that the player manipulates and manages. But that format would be a new mechanic that players might have a hard time accepting and anyways who wants to do supply each turn. Instead I examined supply systems from all the computer games of the genre, read a little on logistics, and designed something familiar to all computer wargamers. The supply system allows for operational action and strategic planning where sea and air control becomes paramount.
Supply Stockpiles – These are stored supplies that represent food, uniforms, helmets, ammunition, spare parts, etc. Each strength point of a unit uses 1 supply stockpile per turn.
Main Supply Sources – All players have main supply sources from production producing urban resources. They provide unlimited supply stockpile to units each turn.
Main supply sources provide unlimited supply for units. Port supplies provide limited supply for units in the form of supply stockpile. Port supply and supply stockpile are limited by two factors, the size of the port and the distance from the port.
Port Supply Sources – Each port size value yields 20 supply stockpile. 1 stockpile supplies 1 strength point of land or air unit. Any unit within 10 hexes of a port pulls from the stockpile to keep it in supply and gets effectiveness recovery equal to the supply level of the hex they are in. If there is not enough supply stock pile it tries to pull from another port. A unit that pulls stockpile from a port 11-20 hexes away uses 4 supply stockpile to supply 3 strength of unit. A unit 21-30 hexes away uses 2 supply stockpile to supply 1 strength of unit. If there is not enough stockpile a unit gets a fraction of effectiveness recovery of what is there. If a unit is in a supplied hex but there is zero stockpile remaining it will only have its supply level replenished by not its effectiveness.
Naval Supply Sources – Fleets can move to a coastal hex, use beachhead supply, and supply units on the coast. Naval supply recovers their unit supply level and gains each unit +6% effectiveness. While this helps units stay in supply it is inferior to having units in main or port supply.
Map Supply Level – This indicates the quality of supply given on the map. As long as a main supply source traces through undamaged rail it stays at a maximum supply level of 9. On hexes that are not rail this number gets reduced by the motorized movement cost of the hex. A road removes terrain movement costs. Once a hex is zero supply level it is no longer in supply. Supply levels directly affect how much efficiency a unit recovers a turn. Each supply level recovers 2% per turn.
So what does this represent? When off a rail line supplies need to be driven by trucks or walked by horses. Fuel will be spent driving, rations will be spent supporting the supply convoy, spare parts will be used to repair the supply truck. The farther you go the less you get.
Headquarters – An HQ that has a supply level of one or more will increase all supply levels within its command via controlled hexes that by moving it can reach by +1. This means even hexes out of range of the original supply line can be increased. HQs can’t chain together. HQs also offer an effectiveness recovery bonus of +4% for any unit within its command range of 5 hexes. So while units can operate without an HQ it is better if they have one supporting them just for supply and effectiveness recovery purposes.
Hex Control – If an enemy unsupplied hex borders a friendly supplied hex the control converts to the player with the supplied hex that borders it at the end of each turn.
Units have two factors that are affected by their supply status. How long they can stay out of supply and how effective their fighting power is. If their unit supply level gets low movement is affected. Once their supply runs out their effectiveness starts taking reductions. Many turns not being in supply affects their health.
Unit Supply Level – Units can stay out of supply for 3 turns before serious lack of supplies penalties occur to the unit. Supply trucks can increase a unit’s supply level to 4 if they start in main supply. Supply air drops maintain their current level of supply of at least 1.
Unit Effectiveness – Supply directly impacts how much effectiveness recovery a unit gets. This represents spare parts, food, fuel, fatigue, and moral in one attribute. Map supply levels and HQs modify how much is recovered. The percentage of effectiveness the unit has is a direct modifier to its combat factors.
Supply Trucks – The use of a supply truck on a land or air unit already in map supply increases their unit supply level by +1 and increases their effectiveness by +6%. You can go over 100% for a maximum of 110% effectiveness over 3 turns of the unit doing nothing but using supply trucks. A player can’t use a supply truck with a unit not in supply. Supply trucks are expended upon use.
Oiler – When a naval unit is at sea they are in an out of supply state. A naval unit with a zero unit supply level can’t attack and defends at 50% its effectiveness. The resupply button uses an oiler supply consumable and replenishes the fleet’s supply level to maximum. Oilers are expended upon use.
How does this work to mimic real logistics?
With this system I can resolve a common concern wargamers have on how to handle North Africa supply for the Axis or D-Day supply for the Allies. The number of ports you control and the distance from those ports affects the effectiveness recovery of units overseas.
For the Allies invading France is as much about getting a foothold as it is getting ports. Now Cherbourg and Antwerp have importance. The type of units the Allies have on the ground in France have importance.
For the Axis the North African Campaign can’t be won just by brute force. Positions like Crete and Cyprus are important for long range strikes, sea control, and a supply source for air units. The Allies have better port supply than the Axis in that theater but on the border of Egypt and Libya is no man’s land where each port becomes vital.
Units also have different supply costs. Any oil dependent unit will cost 10% more supply stockpiles to supply overseas. This means armor, mech, and air units take more supplies than just infantry type units.
Naval Unit Supply and Oil Use
Naval units are unique in WarPlan in how they are supplied. A fleet at port simply gets supplied. While fleets use vast quantities of oil to operate in WarPlan they only use oil when out at sea regardless of their actions. Land and air units use oil when they move and when they attack. Submarines have 5 unit supply level and can go up to a 7 unit supply level if they have long range submarine advancement. All other naval groups have a 3 unit supply level. In naval supply being at zero unit supply means that fleet can’t attack another fleet and will defend at 50% their combat firepower but can still move.
How is port supply stopped? How do I supply invasions?
If you read the naval system post you know that ships and planes can interdict most supply shipments into a port by controlling the seas around the enemy port. At the same time supporting navies can send ships to the area to protect those same supplies. Invasions are done in a similar fashion, by sea control. Players can use ships on the coast to supply units on the beach or within 1 hex of the fleet location as if those units are at a map supply level of 3. But time is short as the supplies these units are getting are not as good as units in main or port supply.
In the Pacific theater you will see more use of the naval supply run to island groups under enemy air attack. A player can even do the Tokyo Express sending closer fleets on night missions to supply land units.
So how does this compare to reality? Usually the largest effect is a lowering of the recovery of effectiveness for units. For example the Italian navy actually delivered most of its supplies to the North African forces and technically performed exactly what it was supposed to do during the war (Struggle for the Middle Sea: The Great Navies at War in the Mediterranean Theater, 1940-1945 by Vincent P. O'Hara). The times they did fail usually had to do with the specific supplies they were shipping like needed fuel or tanks that by chance got sunk. The port stockpile reduction due to naval interdiction is reflected in effectiveness recovery levels based on port stockpiles. As a side note Malta is of some importance in WarPlan as it is 8 hexes away from Tripoli and a naval base. Placing a tactical support air unit in Malta and a submarine will affect supplies to Tripoli. Since Tripoli is far from Egypt supply cost is doubled so every interdiction is critical to Axis forces.
As for the Allied invasion of France in 1944 they still have to protect their supply lanes. A negligent Allied player might find a fleet or 2 of subs impacting their port supply just enough to cause stockpile problems near the front.
With this supply system players need to think about their overseas supply situation more carefully protecting vulnerable lanes and attacking enemy supply lanes. It simulates the complexity of logistics in a way that can be balanced for fair play and easily understood. In beta testing players are enjoying how the ebb and flow of the North African campaign is working. I think this is one of the more interesting aspects of the game that allows players to think about naval and air strategies that intertwine along with supply situations without overwhelming them. The intricacies of logistics combined with the game mechanics will make for very good play.