Article on the evolution of the PzC supply rules

[Mr Grumpy]

At the launch of the first PzC title (Smolensk ‘41) the supply rules were both basic in nature and not particularly representative of historical supply issues in the larger scenarios, but as the series evolved two additional layers of supply rules in the form of the Virtual Supply Truck (VST) and Explicit Supply (ES) optional rules were added to improve historical representation of supply issues and provide players with a choice of three different supply models to choose from, of course with more choice has also come more complexity, but I hope this article will go some way to helping players understand their supply choices and the mechanics of how the features operate.

Default supply rules (no supply optional rules selected)

Supply is determined by a unit being able to trace a continuous line of hexes free of enemy units or their ZOC (negated by friendly units in a hex and crossing rivers via bridges or ferries) back to either any map edge (Global supply) or to a friendly supply source (if they included in the scenario), where supply sources exist they take precedence over Global map edge supply, if a continuous line cannot be traced to a source of supply then the unit(s) are considered isolated.

*Note unlike Global map edge supply, supply sources can be located anywhere on a map and not just at the map edge.

At the beginning of the turn the supply value of each hex containing friendly units is determined and this value is used to determine the state of supply for the units in that hex, this value is known as the Local supply value the higher the number (on a scale of 0-100) the greater the odds that a unit will not suffer low ammo/low fuel supply issues. If a unit is isolated then the local supply value is zero.
To view the local supply values go to the “View” tab and then select “Local supply values” and the values will appear on the map, you should only use this feature at the very start of your turn when the values will be displayed on top of your units before you move them.

When using the default supply rules the local supply value is the same as the Global or supply source value regardless of how far from the supply source the unit is and what terrain it occupies, so the advantage of this rule is its simplicity but does not reflect historical supply situations in scenarios with large maps.

Virtual Supply Trucks (Optional Rule)

With the release of the third PzC title Kharkov ’42 a new “Virtual Supply Trucks” supply feature was added to the optional rule list. If there are supply sources included in the scenario and the VST optional rule is selected the base supply rules covering tracing supply and isolation are retained , but supply is only drawn from friendly supply sources located on the map and the game engine automatically calculates the local supply value using a movement algorithm which effectively reduces the efficiency of supply delivery the further you are from a supply source. The algorithm uses the movement cost for a motorised unit in travel mode, hence the road network on a map becomes very important as tracing supply along roads will reduce the amount of local supply value lost as the distance from the supply source increases, on the flip side a unit in terrain that has high motorised movement costs will see a marked drop in the local supply value.

*Note road stacking limits are ignored for the purposes of calculating the VST values and the local supply calculation will be made using the highest supply source value available.
In the best possible situation with supply being traced along a primary road, the local supply value will be reduced by 1 for every 16 primary road hex’s covered.
The advantage of VST is that it reflects historical supply situations with the advancing force's supply reducing and withdrawing/retreating force's supply increasing without really adding any more complexity to the game, the VST rule will obviously have a greater effect in scenarios using larger maps and on very small maps the effect will be negligible.

Explicit Supply (Optional Rule)

With the release of the fourth PzC title Tobruk ’41 a new “Explicit Supply” feature was added to the optional rules list, selecting this rule will only have an effect if the OOB of a scenario supports this feature by including ES units in the form of mobile truck, cart, pack animal and static depot units which actually provide the unit resupply, under this rule supply sources are retained only for the purposes of determining isolation and not resupply.
*Note that the Scenarios containing Explicit Supply unit counters are designated by the small *s* after the number i.e. #01s_Mersa_Brega_31Mar.scn and be aware that some games do not contain any ES scenarios.

Under this rule the local supply values are set at 80, the ES units have two supply related attributes which are the range that they can provide resupply and the amount of supply “vehicles” they possess, to resupply a ES unit must be able to trace a continuous line of hexes free of enemy units or their ZOC (negated by friendly units in a hex) to a friendly unit that is within its range, the ES unit must not be in travel or rail mode (marked unavailable), disrupted ES units have their supply range halved and a broken ES unit has a supply range of zero and can only provide supply to units in the hex it occupies.

Any friendly units that are low ammo/fuel that meets the above criteria will be resupplied until the ES unit vehicle value is reduced to zero at that point the unit removed from the map.
Mobile ES units will arrive as reinforcements as detailed in the scenarios reinforcement dialogue, ES units can be “captured” and its vehicle supply value can be used by the opposing side when the unit is left alone in a hex after a successful enemy assault, the value of the ES units vehicles are halved if this occurs.
ES units have no ZOC and if a player does not want his mobile ES unit to provide supply they must be left in travel mode or out of range of any friendly units that might become low ammo/fuel, a static depot cannot be placed in travel mode.

The advantages of this feature is that it allows players to micro manage their supply determining which units are resupplied, it also allows players to recreate those historical situations like the North African campaigns or campaigns fought in difficult terrain where supply was a vital element in those operations, unlike the other supply rules this feature allows units to be resupplied even if they are isolated provided they meet the ES resupply criteria.
The disadvantages of this feature is that it adds to the number of units a player has to consider when moving his forces and requires a player to plan very carefully where his supply units are located and the value of ES vehicles required if parts his forces are not to suffer low ammo/fuel effects be that on the offensive or defensive.


So when selecting your supply rules...

• The default supply rules are used if neither VST nor ES optional rules are selected.
  
• VST cannot be used if the scenario does not contain supply sources, in this situation selecting the optional rule has no effect and the scenario will use the default supply rules.
  
• ES cannot be used if the scenario OOB does not support this feature, in this situation selecting the optional rule has no effect and the scenario will use the default supply rules.
  
• If both VST and ES optional rules are selected and the scenario can support both feature then ES takes precedence over VST or if only one of the optional rules is supported then that will be used.
  

I would like to thank Glenn Saunders for coming up with the original idea for this article, unfortunately the original article that was displayed on his website has been lost but I did manage to recover some of the original images, thanks also to Volcano Man and Ricky B for their input and checking my facts were correct.

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[Glenn Saunders]

Jezz I thought it looked familiar but I certainly wasn't going to say anything. :)
Cheers guys

[Compass Rose]

Great stuff.

Thanks for resurrecting it!  

[Mr Grumpy]

No problem Glenn, for some reason (lost in time) I had stored the images from your article in my Blitz files area, so by looking at them I managed to fill in the text to match your article a closely as by memory would allow.