Space saturation?

[potski]

Movement penalties

Instead of a limit on the number of units that can occupy a province (be stationary within it), a more reasonable rule that could be implemented would be to introduce movement penalties if those Divs all attempt to move at the same time. If 50 Div stacked in London are forced to retreat after defeat in battle then even in a very high infrastructure region, with good terrain, the chaos on the roads would be terrible, and cause much more risk of whole units being cut-off and destroyed. In the Ardennes with few good roads 50 Divs could never advance together. A typical INF Div advancing in column up a single road might be spread out 10-15km. If there are only three roads in a province such as Bastogne and the Divs can travel 30km per day into it if it is undefended, then only about six Divs can advance each day.

It seems to me that movement restrictions might reasonably be placed on the advancing forces based on the frontage of the province. If the terrain/infrastructure limits the number of Divs that can enter combat on the frontline, then it must also limit the number of Divs that can move at any one time. What you would then get if you order 50 Divs to advance into a province is that most are queued up waiting for a slot to move in. It might take about 8 days for all 50 Divs to move through Bastogne.

Hansag is right, that the presence of military police, should help reduce the problem. But also Corps/Army HQs which can direct the movements of so many Divs should give some bonuses.

 

[potski]

Supply

What certainly should be difficult is to supply 50 Divs in a province. IRL in 1940 a marching INF Div would require about 300 tons of supplies every day. An ARM Div more, a GAR Div less. That's 120 x 2.5 ton trucks running continuous convoys for just one Div, assuming they can make a return journey to the supply depot each day, and they are all operational. For 50 Divs you would require 6000 trucks at least. Again, the problems of operating them are much more difficult in low infra/difficult terrain provinces.

It seems to me perfectly reasonable to place an upper limit on the amount of supply that can reach Bastogne in the Ardennes each day. So that if you had a situation that you had managed to move 50 Divs there, you would not be able to keep them supplied.

For London, supply should not be such a problem. If the infrastructure and local economy can keep 8 million people fed and supplied with the essentials of day-to-day life then it seems reasonable that the army should still be able to keep 50 Divs supplied.

This depends on a much more sophisticated overland supply model than exists in HOI2, and Johan has promised this is an area that they are developing.

 

[potski]

Blockade port

To me, the issue with Gibraltar is still one of supply and movement, and special rules concerning its geographical area are unnecessary. You are able to maintain a stack of 15 Divs in Gibraltar to defend from attack from Spain, even if you constantly lose Divs in a series of battles over several months and from constant bombing because:
1. Transport fleets are able to land with little difficulty
2. Convoys are able to bring virtually unlimited supplies

In HOI2 it was difficult to prevent the TRP and convoys reaching Gibraltar because you needed to put your naval forces on a misson that would cover a very large area of the Atlantic Ocean off the coast of Spain and Morocco, and the mission would operate in the same way as convoy raiding in the middle of the Atlantic. This seems to me completely unrealistic, there should be a Blockade Port mission, where your naval forces would take up position quite close to a port, so that it would be virtually impossible to get through. If the UK wanted to land three Divs on TRP in Gibraltar they should be forced to commit a very large fleet to protect them.

Obviously, Blockade Port mission would prevent most convoys reaching the port, but it would also increase the risk to your subs/destroyers etc. from attack from the air, as they would be much more likely to be spotted.

 

[potski]

Supply limits on ports

I've already mentioned the supply requirements for an INF Div are over 300 tons per day, which is about 10,000 tons per month. For Gibraltar, or any island, all of those supplies need to come by convoy ship. Even at peace there is a maximum number of ships that can dock and unload at a port.

In 1939 London was one of the busiest ports in the world. It had a capacity to handle 5,000 ships per month with 11 miles of docks along the river and 1,500 cranes. It's capacity in 1939 was about 4 million tons per month. From that extreme we have ports such as Tripoli in Libya which had a capacity of 80,000 tons per month in 1939. Tripoli can therefore keep supplied about 8 Divs if fully employed on bringing in military supplies. Tobruk had a capacity of around 40,000 tons, and could supply a maximum of 4 Divs.

It is clear that for a realistic logistics model to work in HOI3 the most important change to the game engine is that each port should have a level, say 1 to 10, which determines the maximum capacity per month which can arrive/leave the port. So regardless of how many convoys you have available, and how much supplies are required, only a certain amount can be landed. This capacity should be capable of being reduced by battle damage/air attack.

Gibraltar is an important naval base. Nevertheless, because of it's small population size, it is not a major port. There are not extensive docks facilities, cranes, warehouses etc. My guess is that it's capacity at the very most would be more like that of Tobruk, 40,000 tons per month. If that is the case, then Gibraltar would only be able to sustain a throughput of supplies for 4 INF Divs, and less than this if it was damaged.

The port size should affect not only the maximum throughput but also the maximum amount of supplies that can be stored there. There has to be an upper limit on the storage capacity of the port. I’m guessing that a reasonable limit might be one months worth of supplies. So if a port like Gibraltar is completely blockaded and no convoys get through the port would only be able to supply 4 INF Divs for a month. Once those supplies ran out then the defenders would operate at the out-of-supply penalty, and the defence should soon collapse.

This seems to me the best solution to the problem of Gibraltar and some of the very small Pacific islands. Their ports should be unable to sustain large stacks of Divs for any length of time, even operating at maximum capacity. The practical numbers of defenders would be reduced even further if the supply is properly interdicted by a naval Blockade Port mission and ports can be damaged to reduce their capacity by an air mission. It might be possible then to cut-off supplies to these provinces completely.

Edit: monthly cargo capacity of London of changed, see posts #32 and #33

 

[potski]

General supply by convoy

I think it would not be too difficult for the Devs to choose some rough figures to apply to every port regardless of whether it was on a small island. They don’t have to be too exact, on a 1 to 10 scale. But there is a major consideration that has nothing to do with small islands - port capacity applies equally to large islands, and even whole continents.

It should not be possible for the Axis to supply very large forces in North Africa through convoys arriving at Tripoli (Lvl 4). As mentioned, at maximum capacity this port should be able to sustain 8 INF Divs. Benghazi (Lvl 2) and Tobruk (Lvl 2) would be able to sustain a further 8 between them. This makes a maximum of 16 INF Divs which can be deployed to Libya and maintained in-supply during a long campaign. The overall numbers are further reduced by the introduction of ARM Divs, which require more supplies than INF and also require oil, and also the introduction of air units.

You can then get a situation as happened IRL with Rommel’s forces. Tripoli, Benghazi and Tobruk could barely sustain 13 units:
2 ARM Divs
1 full-strength INF Div (GER 2-3 Inf.Bde’s)
8 below-strength INF Divs (ITA 1-2 Inf.Bde’s)
1 air unit
Then convoy raiding actually reduced the supplies arriving below that.

For this to be meaningful, one other major change from HOI2 needs to happen - you must be able to run convoys to more than one port on any island. If the Axis control Tripoli, Benghazi and Tobruk, they will have to run convoys to all three ports. In most cases, this should be handled by the AI auto-convoy system. If an Axis player captures Tobruk they should just have to designate it as a port supply base, and let the AI bring in the additional supplies. In the unlikely event that the Axis were able to successfully invade Egypt and capture Alexandria then they could also designate that as a port supply base. Since this is a much bigger port, then if the majority of the Axis forces are based in Egypt they can be adequately supplied by Alexandria. You should be able to remove Benghazi and Tobruk as port supply bases, and the AI would move any existing supplies stockpiled there to another base, and stop bringing any more.

 

[unmerged(42794)]

I really like your suggestions regarding port sizes. Hopefully the unused supply distance modifier will actually play a role as well. Then suddenly capturing Alexandria would mean a major blow for allied troops, and a major gain for Axis. It should matter that they would have to now supply the allied forces across the desert from Tel Aviv.

 

[Radu]

Indeed! Ports should be absolutely necessary as a bridgehead expands into a theater in its own right. Good job pointing it out Potski.

A port level X should have a "Convoy Processing Capacity" Y,result in only Z amounts of supplies+fuel at any given time.

 

[Shabz]

Well, it should then be extremely difficult to upgrade and make port...

 

[Bobb4]

This should also impact on a landing (D-Day) How long could you supply an army before your need to capture a port was your only means of survival.
I really like this!
It would stop a lot of fake landings.

 

[unmerged(127904)]

The same happened in Market -Garden. Roads where filled with troops (the operation limited to specific width).
I fully agree with that concept.
DDay without ports - complete failure. They should implement all u write here. At least in some extend.

 

[potski]

Yes, the movement penalties should definitely apply for a landing. You have the old HOI2 limit on the number of Divs that can take part in a landing, and this will be replaced by new rules severely limiting the frontage for the combat on the beaches. If the assault is successful, and you capture the province as a bridgehead, then the same frontage restriction should make it impossible to land more than one or two Divs at a time. IIRC in HOI2 if you controlled a province (so there was no combat) and you had the TRP to do it, you could land 20 Divs simultaneously.

Even if you control a port, the port size could also restrict the number of TRP that can unload at any one time. It's much easier to unload a ship in a harbour than on a beach, but even Brest or Cherbourg couldn't allow you to unload 20 TRP simultaneously. Each TRP represents a small flotilla of ships, IIRC a standard US Div would require about 7 ships to transport it. So even unloading 3 TRP at a time means about 20 ships tied up in the harbour. And pre-containerisation, unloading a large ship is not a simple job for the dock workers.

You could also have it so that if the port is being used FE 10 days unloading TRP, then it can't also have incoming supply convoys.

 

[EntropyAvatar]

In 1939 London was one of the busiest ports in the world. It had a capacity to handle 5,000 ships per month with 11 miles of docks along the river and 1,500 cranes. It's modern day capacity is about 400,000 tons per month, but my guess it's capacity in 1939 was only about 200,000 (it has expanded along the river with massive bulk oil and container handling facilities built since the war).

If you had 5000 ships processed per month, and only 200,000 tons of cargo, that means the average load for each ship was only 40 tons. If you assume 200,000 tons per DAY, then each ship would have 1200 tons of cargo. A much more reasonable number I think, assuming a lot of the ships are fairly small.

 

[potski]

If you had 5000 ships processed per month, and only 200,000 tons of cargo, that means the average load for each ship was only 40 tons. If you assume 200,000 tons per DAY, then each ship would have 1200 tons of cargo. A much more reasonable number I think, assuming a lot of the ships are fairly small.

My apologies, I've missed a "0". London currently handles about 50 million tons per year, which is about 4 million tons per month, not 400,000 as I calculated.o

I wondered how come the biggest port in the world was only handling three or four times as much as Tripoli! Should have rechecked the maths.

I've also now found the correct figure for 1939 - London was actually handling more then, than today, not less as I guessed. It was about 60 million tons per year.

That massive discrepancy between the really BIG international ports (London, New York, Rotterdam, etc.), and the run of the mill local ports dotted along the coast, really emphasises the point that all ports are not equal, as in HOI2.

The true average cargo figure is around 1000 tons per ship, which still seems very low. I can only guess there must have been alot of small ships at the time. But it is an interesting statistic, because if a WWII standard INF Div needs about 10,000 tons of supplies per month, then that's around 10 cargo ships per month. 15 Divs in Gibraltar (or any other small island) will require 150 ships per month to arrive in the harbour, and they must have the port facilities to actually unload those ships.

 

[Alexander Seil]

It's not entirely HoI2's fault that the port capacity was not properly modeled. As far as I know, the only other PC wargame where this is a consideration is War in the Pacific and its immediate relatives. Although I do hope that HoI3 puts some detail into this. No more stacks of doom in Central Africa.