Repairing LI - case study

[Yaab]

Base: Changsha

LI damaged: 144

Supply expended for repairs: 144,000

Repair time: 12/8/1941 - 5/5/1942



Repairing 1 damaged LI costs 1,000 supply, thus it takes 1000 days to break even on this investment. That is the general rule of thumb. I tried to gauge whether this rule of thumb is sound using Changsha as the case study.


During 12/8/1941 - 5/5/1942 period I will expend 144,000 supplies to repair 144 LI there. This newly repaired LI starts generating new supply as soon as it is repaired. Each day the number of this newly produced supply will be growing by one and added to the supply produced beforehand in the following matter:


1:1
2:1+2
3:3+3
4:6+4
5:10+5
6:15+6
7:21+7
8:28+8
9:36+9
etc.

After 144 days, this new supply pile will reach 10,050 supply points. So I have expended 144,000 supplies, but the repaired industry have already repaid 10,050 supplies. So 133,950 supplies have to be repaid from 5/5/1942. This will happen after 930 turns (133,950 / 144 daily new supply in Changsha) on 19 November 1944. This is the day I break even. If the war lasts until 31 March 1946, the Changsha investment will give me a windfall of 67,248 supplies (144 supplies x 467 turns).

To conclude: the 1000 days rule holds, albeit modified downwards due to new supply generated during the repair period. In order to ripe the rewards of your investment, you need to start repairing as soon as you can, preferably starting on turn 2. The repairs make most sense if you plan to hold the repaired base until the end of the war, preferably protected from enemy intervention i.e. air raids, which can damage the industry.

[Skyros]

You also have to maintain at least 10,000 supply at the location or repair will not happen. This could lengthen the time of repair as well as create temporary shortages in supply starved areas.

[PaxMondo]

ORIGINAL: Yaab

This is the day I break even. If the war lasts until 31 March 1946, the Changsha investment will give me a windfall of 67,248 supplies (144 supplies x 467 turns).

Unless the opponent strat bombs your base ... you cannot look at it an say "until the end of the war".

If the base in question comes into strat bombing range, then that industry is in jeopardy. This is the crux of the issue for the IJ, finding a location that is going to be safe for +1000 days to expand LI. There are a few that in most games should be safe that long. Then the next hurdle is "Is that a location where the extra supply will help me?". Finally, and this is the hurdle that I always struggle with: "Can I forego the use of all of that supply early the game when I am trying to expand both my empire and my economy?".

From Dec 41 -> Jun '42 most IJ players are supply limited. You are already short of the supply that you want. You are expanding your factories, expending a lot of supply in conquest (amphib combat eats a lot of supply), and finally you need to reserve many 100,000's tons of supply to potentially repair captured oil centers. So during this time, it is very hard to take another few hundred thousand supply and build more LI even though you know you would like to have that working for you in '45.

[Yaab]

The only "safe" place for the Chinese to repair LI would be Chungking (has 17 damaged LI). After repairs there have been completed, the investment will break even after 992 days, which is 15/9/1944. Until the end of the war on 31 March, 1946, the repaired LI in Chungking will produce a windfall of around 9100 supplies. Not much of a help.

[Bullwinkle58]

ORIGINAL: Yaab

The only "safe" place for the Chinese to repair LI would be Chungking (has 17 damaged LI). After repairs there have been completed, the investment will break even after 992 days, which is 15/9/1944. Until the end of the war on 31 March, 1946, the repaired LI in Chungking will produce a windfall of around 9100 supplies. Not much of a help.

In my game Lokasenna bombed out over 100 points of LI before beginning the siege. Think it's worth it to fix? [:)]

No place in China is safe to repair industry.

[PaxMondo]

ORIGINAL: Bullwinkle58

No place in China is safe to repair industry.

Which is where I am at on the IJ side ... once the B29 gets in the game I just don't think there is anywhere the IJ has that is safe for very long IF the allied player determines it is worth the cost ...