In IN, provinces that fulfil certain criteria are treated as overseas. These provinces get a severe penalty to their tax contributions and don’t generate any production income. Instead they generate tariffs, which is derived by both the base tax and production income the province would have if it was not overseas. This income is further affected by sea-lane efficiency and added to monthly income.
A province with the distant overseas attribute will generate a monthly amount of overseas tariffs that is dictated by the following formula:
Production income + base tax + workshop + CoT + CoT LV + national focus Monthly overseas tariffs = ------------------------------------------------------------------------ * 0.50 * ( 100% + Modifiers ) * sea-lane efficiency 12
Where modifiers that include:
- National idea: Viceroys: +25% ( : +33%)
- Tropical modifier: -50% ( : No penalty)
- Blockaded province: -100%
- : Largest trader in slaves: +25%
It is important to note that many of the modifiers that affect taxes do not necessarily affect tariffs.
As it can be seen from the formula, the actual distance of the province from the capital in relation to your supply range doesn’t affect the amount of tariffs gained.
Another point worth noting is that the tropical penalty is particularly damaging for tariffs, as they apply both to production income (that is component of the tariffs) and to the tariffs themselves.
Sea-lane efficiency determines the percentage of overseas tariffs that actually get to your monthly income. It is determined by the total number of big and light ships you have and the total number of overseas provinces you own:
This number has a maximum of 100%.
The ships that guarantee your sea-lane efficiency just need to exist and they grant you the efficiency even when they are docked.
A province is considered overseas when all of the following conditions apply:
- The province is in different continent than the capital.
- The distance from the capital is greater or equal to 250.
- Doesn’t have a land connection to the capital.
It seems that the supply range doesn’t determine overseas attribute.
It also seems that the only way to change the overseas status of a province is to either establish a land connection, or move your capital.
Difference to normal provinces
An overseas province differs than a normal one in the following aspects:
- The province gets a distant overseas -90% modifier to its taxation and census taxes.
- No production income is generated.
- No income from tolls is generated.
- Overseas tariffs are generated instead.
- Missionaries to this province cost 75% more.
- Spy defense against operations in this province is 5% lower.
- Troops take 50% more time to build.
- Ships take 100% more time to build.
- Garrison replenishes 5% slower.
- Penalty of -50% to manpower from this province.
- This 0.5 stands for _EDEF_TARIFF_BASE_ in ..\common\defines.txt.