This help page gives an overview of the economic model used in SAS.
In particular it summarises the information you need to know when creating campaigns and setting the economic factors at various ports that drive production and sea trade.
It also summarises how the computer AI assess things when your 2IC creates convoy missions for you, and gives a schedule of how resource points (RPs) can get expended or lost.
Almost every activity in SAS has an economic cost. In real life this was measured in things like dollars and gold as well as in usage of key war material such as steel and oil fuel and of course usage of manpower.
In SAS, all costs are reduced to a single scale - the resource point (RP). You produce RPs in your factories from materials available locally or convoyed in. You expend RPs in many ways, and can also 'lose' them directly and indirectly as enemy attacks cause damage to key assets and facilities.
In SAS, ports are the key to economic prosperity. Ports not only provide bases for building, repairing, rearming and refuelling your ships, and usually have operational airfields nearby for offensive and defensive aerial operations; they also are the only source of continuing economic wealth generation for you.
Apart from the resource points (RPs) you start with at the beginning of the game - that are stockpiled at your ports - you gain further RPs soley from production by factories in and 'around' your ports.
In the simplified economic model in SAS, factories use raw materials to produce war material.
These raw materials are of two kinds:
Any of your ports can be both a source of materials as well as having factories for production. The capabilities of each of your ports are set initially, when a campaign is created, and then during a game those capabilities - or infrastructure - can be improved through investment as well as degraded by enemy attack. The help file what port parameters you can change tells you what you can configure, and how to do it. This help file explains more of the why.
The domestic industry levels at your ports, together with the accompanying domestic materials indices (DMI) are used by the computer when it calculates the total value of your economy.
Changing the industry levels can have a big affect on the value of a country's economy, and hence on the starting odds also.
Your domestic industry factories at each port produce RPs every turn. Any domestic materials available locally get converted to RPs. The formula is:
number of RPs = 10 * the port's domestic materials index * the port's current domestic industry index.
This formula assumes that the strategic turn is the standard 30 days (one month). The RPs produced are directly increased or reduced by increases or reductions in the length of the strategic turn.
To make this clearer, an example from the 'Pacific1' campaign may help. For the Japanese player, Tokyo Bay starts with a DMI of 4 and a domestic industry index also of 4. So, every month, it produces 10 * 4 * 4 RPs, ie 160 RPs. If you were running this campaign with say two week strategic turns, it would produce half that per turn.
The export industry levels at your ports, together with the accompanying export materials indices, are used by the computer when it calculates the total value of your economy. The value of every possible convoy route between your ports is calculated, and a weighting is also applied based on how short the route is: shorter routes are worth more because more goods can be carried in a given amount of time.. The value of a route is directly and inversely proportional to its length.
Changing the industry levels can have a big affect on the value of a country's economy, and hence on the starting odds also.
Your export industry factories at each port produce RPs in two ways:
The AI generally tries to maximise the value of cargo carried. Every turn, at every port where enough merchants and escorting ships can be assembled to create a convoy (subject to other mission priorities), the computer calculates the most valuable destination for the convoy to sail to. It does this first by calculating the theoretical value of every trade route between the current port and every other friendly port, based on the export materials indices and export production indices at each end, and then dividing by the route length. These calculations are dynamic, ie they take into account the current industry levels at all ports - so damage by enemy attack or improvements through infrastructure investment can change the way convoy routes are assessed.
If no suitable port can be found, it does a secondary calculation, looking for the port that is the most valuable source of export materials, but again dividing by the route length. (The reason for taking route length into account is to simulate the fact that shorter routes have quicker turn around times, ie they allow more trade for a given volume of shipping).
Therefore, when creating campaigns, the best way to simulate active trade routes that the AI will try to stick to is to have some ports with highish EMIs and low or non existent export industry and other ports with highish export industry but lowish or non existent EMI. The 'Atlantic1' campaign is modelled this way - to simulate the convoy traffic between the US east coast and Britain, and also between South American ports and Britain.
Note that the AI also has other priorities than pure economic convoys to think about. It also tries to maintain minimum RP balances at your ports - so sometimes preference is given to convoys that simply transport RPs (ie finished war material) from a port with a surplus to one with a forecast need. (The forecasting of needs is itself quite sophisticated and includes calculations of likely RP usage by garrison troops).
Finally, an overview of RP usage in the game - the expenditure side of the balance sheet - may be useful.
Almost every activity in SAS has a cost. The following table summarises how these costs are calculated.
| Activity | RP Cost |
|---|---|
| Ship building | 1 RP per 100 tonnes full-load displacement (eg a battleship of 45000 tonnes full-load costs 450 RPs to build) |
| Ship refuelling | 1 RP buys 500 tones of high-grade fuel for naval ships (Merchant ships are assumed to use diesel, the consumption of which is not costed) |
| Rearming of shells | Equipping a 45000 tonne battleship with a full complement of shells costs 20 RPs. Costs for other ships are scaled according to displacement |
| Rearming torpedoes | Torpedoes cost 1 RP for every 4 |
| Rearming mines | Mines cost 1 RP for every 30 |
| Maintaining troops | Here, there are two scales of costs: normal and combat; and RP costs increase substantially for troops that are better equipped and especially for those that are more mechanised. For example, a totally non mechanised unit of 10000 men, with very poor equipment requires only around 4 RPs normal supply (for a 90 day period), and .12 RPs per day combat supply. The same sized unit with average degree of mechanisation and equipment would require over 12 RPs normal supply and nearly 1 RP per day combat supply. If the unit was totally armoured and equipped extremely lavishly it would require over 25 RPs normal supply and nearly 2 RPs per day in combat. For troop supply, 1 RP equates to 1000 tons of supplies of all kinds - food, ammunition, fuel, medical supplies and so on. |
| Building aircraft | Cost reflects size and complexity of the design. A small very simple aircraft may cost less than a fifth of an RP. Big heavy bombers may cost close to over 1 RP each. The cost is an amortised cost of not only the materials and labour to produce each aircraft, but the set up costs for the factories themselves. |
| Repairing ships | Damage to ships is shown in most dialogs in the game as a percentage of the cost to build the ship. For example a '50%' damaged 5000 tonne cruiser would need 25 RPs to repair. The relationship between actual damage and the percent damage figure is somewhat complicated but accounts for flooding, structural and non-structural damage, damage to turrets and machinery, and so on. |
| Building docks infrastructure | It takes 200 RPs to raise the docks infrastructure level by one, at any single port |
| Building port defences | It takes 50 RPs to raise the port defence level by one, at any single port |
| Building airfield infrastructure | It takes 20 RPs to raise the airfield infrastructure level by one, at any single port |
| Building industry | It takes 100 RPs to create a level one industry from nothing. It gets increasingly more expensive to increase industry by one level as industry gets bigger and more complex. For example, it would take 1000 RPs to raise industry from level 9 to the maximum level of 10 at any port. |
RPs are lost when