[Mass Combat] Cutting supply lines

[Polydamas]

Originally Posted by Rupert

Having a quick read through them, I'm not sure that Sea logistics forces should cost twice land logistics per unit of troops supported - sea transport is cheap compared to land, and always has been.

I think that would be reasonable.

Bowmen have Maintain 8k
Musketeers have Maintain 6k
Riflemen have Maintain 12k

Horse Archers have Maintain 30k
Cavalry Pistols have Maintain 20k
Mounted Rifles have Maintain 20k

So the higher-TL the troops, the more of their Maintain is fuel / ammunition / durable goods, and the less food and fodder and clothing. But this is really technical, the details are hard to research (especially for adventure-friendly situations like technicals and men with rifles, mortars, and HMGs moving across a failed state) and its likely to turn into the situation where 1 or 2 people in the group are really excited and everyone else is bored stiff. If you know enough to want to use detailed rules, you know enough to handle them narratively.

I would suggest that anyone interested gamify the scholarly books on the subject like:

Donald W. Engels, Alexander the Great and the Logistics of the Macedonian Army
Jonathan P Roth, The Logistics of the Roman Army at War
Martin van Creveld, Supplying Mars: Logistics from Wallerstein to Patton

There must be something on the logistics of indigenous forces in Afghanistan or the Libyan Civil War but I don't know what. If you understand logistics and GURPS, you can make something which models the specific situation your players got themselves in to, whereas building a general model which is simple enough for a game with fantastic elements and imaginary worlds is hard.

[Polydamas]

Originally Posted by Rupert

Having a quick read through them, I'm not sure that Sea logistics forces should cost twice land logistics per unit of troops supported - sea transport is cheap compared to land, and always has been.

Naval Logistics can support naval elements as well as land elements based in a port, and historically navies were a problem because they cost cash and there was no way around that. Agrarian societies are good at collecting and redistributing crops and cattle and fodder, not always as good at turning that into cash and hiring skilled workers and buying rare materials and finished goods with it. maybe they were thinking of something like that? Or data from 20th century militaries on tooth-to-tail ratios in armies, navies, and air forces?

[Polydamas]

A pretty typical means of cutting supply lines is having some fast-moving or concealable troops near the route and attacking things passing along it.

Another is the enemy having a superiority in light troops, so your men can't go out and collect fodder and grain without little groups being bushwacked.

Another is breaking key transport infrastructure (burning pontoon bridges, smashing bridges, digging up railroads, bombing airstrips). This is often harder in practice than in theory, but it makes for good adventure scenarios. Yuval Harari has a book with a chapter on a raid to destroy the mills that an army needed to grind its flour.

Its not necessarily about occupying a hex.

[Rupert]

Originally Posted by Polydamas

Naval Logistics can support naval elements as well as land elements based in a port, and historically navies were a problem because they cost cash and there was no way around that. Agrarian societies are good at collecting and redistributing crops and cattle and fodder, not always as good at turning that into cash and hiring skilled workers and buying rare materials and finished goods with it. maybe they were thinking of something like that? Or data from 20th century militaries on tooth-to-tail ratios in armies, navies, and air forces?

I'm just thinking that you can move a lot more stuff a lot cheaper by sea than land.

In WWII a liberty ship cost about $2,000,000 and had a nominal load of 10,000 tons (and often carried more). Roughly speaking, a Liberty ship could move that load about a 1,000 miles and then return in 10 days. So it could move 1,000 tons/day 1,000 miles.

To do the same on land via trucks you'd need about 800 trucks, which happen to cost about the same as the ship (They move faster, but are much, much smaller) (at about $2500 each at the time). Capital outlay for the hardware is much the same. However, the ship requires about 40 people, the trucks 1600, just for the drivers, so initial recruitment costs for the trucks is a lot higher.

Then there's maintenance costs - the trucks need 40 times as much food and pay for their crews. They manage to move their 5t load about 7.5 miles per gallon of fuel (on a road) if things go well (37.5 ton-miles per gallon). The ship manages only 0.04 miles to the gallon, but carrying 10,000 tons for over 400 ton-miles per gallon (over ten times the efficiency).

The same sort of effect occurs at lower TLs, with the added benefit for sea travel that's it's faster than moving things by cart or wagon.

At TL5+ railways help with land transport to an extent, but shipping still has it beat.

[Polydamas]

Originally Posted by Rupert

I'm just thinking that you can move a lot more stuff a lot cheaper by sea than land.

I guess the question is do the stats describe Logistics for Navies, or Logistics by Navy ("Naval Logistics: Can support naval elements and land elements at a port")? Because of SJG's taboos against citations we just can't know unless we were in the playtest. I would agree that in general, supporting a land army by sea should be cheaper than supporting it by land.

No School Grognard has some thoughts on Mass Combat after playing a fair number of battles.

What is really cool about GURPS is the simple core mechanics which you can relate to whatever you learn about the real world. Using those two things to model the specific scenario your players have got themselves in is way more practical than trying to create a general model.

[AlexanderHowl]

Traditionally, supplying by sea was more expensive because a) you usually had to pay for the supplies from the source rather than just stealing them while your soldiers were victimizing the innocent locals, b) you had to pay sailors to move the supplies rather than just having your soldiers steal from the locals while they were involved in the victimization of innocent locals, and c) you still had to support a bunch of wagons to transport the supplies from the port to your soldiers.

In general, modern armies work because of access to local seaports, so they can afford to pay extra to avoid having their soldiers depending in the victimization of the locals for supply. Now, while this does avoid most local victimization, modern militaries still have a distressingly high level of local victimization in contemporary wars, but that is more due to the fact that modern militaries have low recruitment standards due to a combination of relatively low pay and relatively low comfort than because of lack of supply. Quality of troops matters for keeping discipline when a force has already solved the supply issue.

Of course, pay and comfort mean different things for different nations. For example, the pay and comfort available to the enlisted people of the other NATO navies are quite generous and quite luxurious compared to those for the enlisted of the US Navy.

[RyanW]

Originally Posted by Polydamas

I guess the question is do the stats describe Logistics for Navies, or Logistics by Navy ("Naval Logistics: Can support naval elements and land elements at a port")? Because of SJG's taboos against citations we just can't know unless we were in the playtest. I would agree that in general, supporting a land army by sea should be cheaper than supporting it by land.

Sure, but your army is then restricted to operating in the immediate vicinity of friendly ports.

Look at the Red Ball Express, one of the biggest logistics operations in history, to keep an army moving ever further from a decent harbor. Capturing Antwerp significantly relieved that pressure.

[Polydamas]

Originally Posted by RyanW

Sure, but your army is then restricted to operating in the immediate vicinity of friendly ports.

Look at the Red Ball Express, one of the biggest logistics operations in history, to keep an army moving ever further from a decent harbor. Capturing Antwerp significantly relieved that pressure.

GURPS Mass Combat pp. 13, 14 has rules for basing your logistics over land from a port, although it looks like you need to buy two complete sets of Logistics Strength.

The Dutch campaign in 1944/1945 is a good example of ways to cut a supply line (mine and demolish the harbour, station artillery covering the approaches) and ways to un-break it. I feel like working out ways to sneak Anti-Aircraft Artillery into the approaches to the enemy's Air Logistics base (hi Giáp!), or taking the castle blocking the mouth of a key harbour (hi Hannibal!), is likely to be more fun in game than a set of hex-and-counter rules.

From the perspective of players at the tactical level, the GM will probably announce "due to storms and the advance on the Rhine, supplies are scarce. This month your unit is on Low Supply. You are especially short on artillery rounds. What are you going to do?" And then scrounging up artillery rounds, or avoiding fighting, or making a plan which does not require a lot of artillery is the adventure.

[johndallman]

Originally Posted by Polydamas

The Dutch campaign in 1944/1945 is a good example of ways to cut a supply line (mine and demolish the harbour, station artillery covering the approaches) and ways to un-break it.

Do you mean the Battle of the Scheldt, which finished during 1944, or a later campaign?

[Michael Thayne]

I suspect land vs. sea vs. air logistics pricing was based 100% on game balance and 0% on realism. Someone figured sea logistics was better because there are fewer choke points at which you could block it, and therefore it must be more expensive for the sake of game balance.