How big is a troopship? [DS/FT/SG2] (and what it all means)

Well,

This follows a discussion alluded to earlier this year, and a far more
extensive one about two years ago on the translation factors. As this
was one of my interests (in figuring out just how huge FT transports
need to be), I've spent quite a bit of time looking at it.

I went with 1 FB Mass = 25 CS (SG2).

Now, what can we fit in 25 CS?
4 CS = 1 active marine (with presumably a half or quarter of a
stateroom)
1 CS = 1 cryosleep marine
A vehicle stored within another (like an SG2 tank) takes up 8/5ths its
space.
1 Mass therefore stores 1 size 3 vehicle. (15 * 8/5 = 24... which is
just about right for a one mass 25 CS storage area).

But then we get into the question of supplies:
How much does a modern mechanized force consume?
I believe I got figures like an average of 10 kg a day in low tempo
operations, 20 kg a day in normal operations, and 40kg a day in high
tempo operations per man. This includes food, water, medical supplies,
ammo, gasoline or other fuels, etc. (Owen, Los, anyone else care to
oppose these figures or suggest some alternates?).

So, we have two approaches: 1 is to assume the quoted cargo space
above includes some amount of supplies (a weeks?) as well as the
marine. Reasonable. The other is to assume supplies are extra.

But how many supply units (we'll call 1 man's supply for 1 day of
normal tempo operations 1 supply unit) can you fit in 1 CS? The
conversion I think I would use is 14 SUs per cargo space. Why - that
is 2 weeks supplies in normal ops! Alternately it is about 560 kg
which strikes me as the CS of 1 marine plus his freezer plus his kit
plus 1 weeks supplies (which we assume as the base 1 mass definition).

So, where does that leave us?
1 CS for a Marine in cold sleep with 7 SUs.
1 CS for 14 SUs.
4 CS for a wake and operational Marine with 7 SUs.

Reasonably, a raider might get away with just this basic loadout. But
any force worth its salt will contain at least a months operational
rations for its forces at normal tempo. That means for every
cryosleeping 1 CS marine, you should figure 2 extra CS for supply. So
in a 25 CS Mass Point for FB, you want to include 8 marines in
cryosleep plus 1 months normal tempo of supplies for them (with 1 CS
leftover).

Isn't that neat? That's about the size of an average squad! So, their
APC (a size 3 beast) takes up 1 Mass, so do they! So 2 Mass for a
squad and its vehicle.

So, let's say we run short platoons (likely in the future, esp given
the cost of troop transport) so we have 3 squads in our platoon. Plus
a command/support squad, with its own vehicle.

So we have a platoon taking up 2 Mass x 4 = 8 Mass.

So a streamlined platoon lander should have 8 Mass devoted to the
platoon. But wait! They'd be in cold sleep. Not such a hot idea. But
you can get away with the same ratio of space (1 space for a trooper)
in "awake" state as long as you aren't assuming living in that - this
is the number used in SG2 vehicle design. So.... we can use the same
mass for the troops, vehicles and supplies. (You could argue even for
the lander that you only need 4 mass as the troops land inside the
vehicles).

The 25mm SG2 lander I treat as if it has 20 internal spaces and it is
size 5. That means I need 2 Mass for it. So it is a 2 Mass Interface
Lander in FT.

But wait, how does this extend to a company?

Let's assume we have a short company with 3 platoons.
24 Mass.
But wait, we're ignoring a command unit plus some support personel,
plus comms, plus EW, plus cooks, plus clerks, plus etc. etc. Plus some
light arty support (heavy mortars for example).
Say another platoon worth.
We're up to 32 Mass.

If independently deployed, they'll probably need a bunch of things we
normally go back to base for - a field hospital on their ship, some
limited airlift capability, etc. The mass starts to add up.
As a rough figure, say we total to 40 Mass.
To land them simultanously, you'd need to add hangar space for 4 of
the 2 mass platoon landers.

Then we think about moving to Battalion scale, with 3 companies.
So we're thinking to ourselves, we'll want some battalion assets like
some howitzers, and we'll need stuff like a B'n HQ. So really, it is
more than 3 Companies. Let's say 3.5 in the streamlined world of the
future. Plus add in some light armour support - a platoon of 4 light
AFVs and their crews. And a battery of 3 mobile howitzers.
So we have 3x40 + (4 (AFVs) + 2 (crew)) + (3 (Howitzers) + 2 (crew)) +
20 (HQ) = 151 Mass. For round figs, say 150 mass.
To land this lot, you probably would do it company at a time, so 4 or
5 of the 2 Mass landers might do.

Note though that a 160 Mass transport (the ship will be bigger) is
starting to get into DN/SDN range and that is only for one battalion
and all shipped in cold sleep!

So, if we move to the smallest formation that could menace any sort of
significant force, the Brigade or Short Division:
3 x Battalions (Line)		    450
1 x Battalion (Support) 		150
1 x Company (attached armour)	    40
1 x Company (attached air)		40
				Total		680

With this, you'd want to be able to land about at least a full
Battalion which means landing 150 mass which means using about another
40 Mass in landers.

So.... A Brigade might be about 720 Mass.

THAT is a lot of mass. THAT is an asset worth killing for an enemy
(the ship cost is quite high). THAT is worth defending. THAT dwarfs
SDNs. Transports in the GZGverse would far outsize warships (think DD
vs Supertanker for an analogy). And that's only arriving to a fight
with maybe 2300 guys.

And Note I've ignored the ortillery aspects of things as well as the
need to protect these large transports - imagine the escort groups!

And imagine the supply vessels - since the numbers above include but
one months ops supplies, or two weeks in high tempo ops. So we're
talking hundreds of points worth of supply to supply a six month
deployment of a Brigade.

WHAT IT ALL MEANS:

Now we see clearly why any starmobile force deployed in the GZGverse
will
1) Be made up of a minimum of REGULAR quality
2) Be well equipped with top of the line kit, especially defensive -
they are worth a lot because they cost a lot to move about so they are
worth keeping alive once at their destination
3) Be of moderate size and not overloaded with a huge number of
armoured vehicles or support assets - enough, but not too many.
4) Never be as big as you want

Local troops have a lot of place in this universe, as do lower tech
locally manufactured arms (esp vehicles!). Also, planetary invasions
are BRUTAL. Only ever done on colony worlds with low pop and low air
defence. To assault say even one country on a major colony of 20
million would take at least 200,000 regular troops - which is about
1000 of these 720 point transports, plus an ungodly amount of supply
points. AND an awful escort group.

The math bears out small forces in the GZG verse - with most battles
being left up to local colonial or militia forces. Regular forces
deployed in small units (company or B'n at most usually) and being of
high quality and high-tech kit. They are also too valuable to lose
frivolously and this would affect tactical thinking - ie victory
conditions. There will be something to be said for having 10,000
screaming IF militia - if all they have to oppose are 150 top of the
line NAC forces.... because the NAC can't afford to be everywhere at
once.

So think about it. The thread was started examining what is reasonable
for an assault lander. Follow it up and you'll see that large
formations would be VERY rare in the GZGverse and you'd NEVER invade a
big high pop planet. Makes getting your claim in on the Rim worlds
worth having that much more important!!!!

BTW - Noam, if you read this, lovely ships (some broken image links I
think though) and great NI work. Now I want some of these NI ships.
You've done great work.

Thomas Barclay
Software UberMensch
xwave solutions
(613) 831-2018 x 3008