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I've been mucking about a lot lately with aerospace design, specifically looking at evolving new stuff from the canon designs, and their huge cargo capacities have me wondering just how much cargo space would really need to required to sustain a ship and its crew for X amount of time.

For reference, a fully loaded Nimitz class carrier has a mass displacement of about 100K short tons. CBT uses metric tons; 1.1 (ish) short tons = one metric ton, so you can do the math. There are many canon warships that can carry at least that equivalent mass in cargo, some much more than that. Imagine stuffing an entire aircraft carrier into your ship's cargo bay and having room left over...yeah. In fact, there's a lot of old Star League designs that theoretically could carry a whole US Navy battle group...carrier, escorts and all.

Now think about this: non-canon, Cray and I have designed 2500 kt megafreighters that can move a million metric tons of cargo. That's the equivalent of carrying eleven fully loaded Nimitz class aircraft carriers. That's eleven times the mass of an 1100 foot long warship with two nuclear reactors, 90 airplanes and 6000 people, plus all the weapons and supplies and everything else that goes into a Nimitz class ship.

You can try translating that into CBT terms if you like, the GDP of a world and all that. But no matter how you look at it, that's an awful bloody lot of cargo.

Just as importantly, there are no canon warships that come even close to having a Nimitz's 6000-person crew. Even if you assume a reasonable number of gunners, the minimum crew for a 2500 kt warship design falls well short of 1000 people. Except for a few special cases (Leviathan, Thera...) even the largest canon warships rarely have more than 1000 TOTAL on board.

US Navy submarines go to sea for months at a time, with a crew roughly comparable in size to a CBT corvette. They only rarely take on supplies during deployment, and they only displace a few thousand tons, not even close to the size of CBT warships. Yet they can sustain their crews and operations for months.

So what the heck is do CBT warships use all that cargo space for, and how much is really enough? Because the cargo space in many or most canon CBT warships certainly is far more than what is actually needed to sustain the ship and crew; in fact, the designs with small to medium sized cargo bays are probably more realistic in that regard.

The rule of thumb I have always used for cargo space is 5% of the ship's mass as a minimum, but even that might be overshooting the target, especially for large warships. For example, 5% of a 600 kt destroyer is 30 kt of cargo, to support a TOTAL crew of 400ish people in a balanced design. Compare that to many canon designs (especially old Star League ships) that may carry 15-20% of their mass in cargo, sometimes even more.

Thoughts?

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Be careful what you wish for. I might let you have it.

We all know that the only reason BT warships have such a large cargo capacity is because the design rules were poorly thought out when it came time to make rules for the ships in the 2750 TRO. All the extra tonnage was dumped into cargo. At that time I just shrugged my shoulders and figured, in story, the large cargo space was needed to transport the large quantity of supplies the Army needed once they landed on a hostile planet.

With that said, I later made good use of that large cargo capacity. In my games the BT warships have to carry a large armor, ammo & important spare parts cache. In space if you cannot fix a critically damaged part to make it to a habitable planet then you are FUBAR'd. And even more importantly I always thought they carried a rather large water supply in several places throughout the ship. Plus if that ship has Aerofighters, small craft and dropships then I figured on a little extra fuel and items for those craft. So with that in mind I figure it is really up to the particular GM if they wanted to play a detailed gamed or not. I personally kinda like the detailed games, especially if you want to role play the ships.

Lets take a Cameron Class Battlecruiser as an example. I would do the following as necessary spare parts/supplies ...........

Repair Components
Armor Plating - 500 tons
Internal Structure Repair Components (plating, fittings, wiring, components) - 17,200 tons (2% ship weight)
Critical Parts (FC-Computer, KF-Parts, Fuel Pumps, Controls, Radar, Computers, Bridge, Attitude Thrusters) - 11,770 tons (3% components total weight)
Extra Jump Sail - 73 tons

Ammo Resupply:
Nac/25 (.6 tons or 1,200lbs/shot) - two complete reloads = 120 tons
Missiles (KW-50 tons, WS-40 tons, BC-30 tons/each) - two complete reloads = 3,280 tons

Extra Consumables
Crew Food (6 months) - 300 tons
Crew Water (6 months) - Crew - 250/tons for consumption, 2,500/tons for non-consumption, 5,000/ton reserve = 7,750 tons
Extra Fuel - 10,000 tons (Aerofighters, dropships, small craft, shuttles)
Repair Parts & Ammo for Aerofighters - 500 tons (list them if you want)

TOTAL CARGO TONNAGE USED - 51,493 tons
REMAINING CARGO TONNAGE - 133,501 tons

So you can eat up quite a bit of cargo with just BASIC stuff carried on board a ship that is really needed, but has honestly never been taken into account!



NOTE:
A.) Always figured 200 tons of IS Repair Components material for each point of IS Damage. This is only a temp repair and a shipyard is necessary for permanent repairs.
B.) Water = 240 gallons/ton: I figure 1 gallon/day for consumption per crewman (drinking/cooking), 10 gallons/day for non-consumption per crewman (toilet/shower - recycled to some degree), 1.2 million gallon reserve

When I built the Sub-100kton Frigates for my Human Sphere I tried to keep cargo size around 1,000 tons or so. I was thinking between 1 and 5%. Of course, those were designed to work in tandem with old Star League battlewagons, or to support star systems. Many of them did not have that much.

The reason I've always assumed the Star League ships had so much cargo space is that they were built to help bring supplies for planetary invasions in war and planetary disaster relief in peacetime.

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Medron Pryde - The Great and Terrible
[img]http://faileas.greywolf.googlepages.com/WOTD.png[/img]
[url=http://www.pryderockindustries.com]P.R.I.[/url] - The home of BattleTech programs and files
"I'm gonna Tea Party like its 1776." - Medron Pryde
Who is John Galt?

Of course, I have always assumed that at least part of the cargo space is reserved for the needs of the crew and ship. For the crew you'd have food, water, personal expendables like toiletries and uniform items, medical supplies and so on. For the ship, you'd have spare parts and equipment of many kinds for maintenance, repairs and damage control. I haven't ever gotten as detailed with it as Highball, but I have made a few specific considerations...

- As far as actual content goes, I assume no ship would ever leave port without everything needed to maintain airtight integrity and life support. Hull patching kits, replacement air filters, compressor and pump parts, whatever. Also important is your KF drive, without which you are stuck wherever you were when it broke; while ships can't carry spare drive cores, they should certainly have spares for power and peripheral systems, including extra sails and sail lines.

- It is important to remember that when you're talking about "spare parts", one ton is a very variable thing. Speaking from my Navy experience, one ton could represent a single large item such as a pump, or it could be a collection of smaller items, such as a score of valves or circuit breakers, or a billion little rubber O-rings. Most ships would also carry a certain amount of bulk material such as piping, spools of cables and sheet metal, which would be used in performing repairs and damage control. Ships typically need and carry many more of the smaller items than large ones, so by the time you're done accounting for and consolidating all the little things, even just a few hundred tons of spare parts actually represents a lot of stuff.

- For warships, I usually ascribe an amount of cargo space for supporting the small craft and fighters equivalent to the mass of the bays. For example, a squadron of six fighters would need 900 tons for fuel, ammo and spare parts to keep them flying. I don't write it down separately, but I do allow for it in my head during the design process.

- Warships and jumpships carry dropships, and I assume that they act as mother ships for the dropships' needs. The dropship crews use the mother ship's grav deck, and since most non-cargo dropships have limited cargo space, part of the mother ship's cargo space provides supplies and support for the dropships as well.

- On transports like the Carrack or Volga, I usually assume that a certain round amount of cargo is the actual cargo being shipped, while the odd leftover amount is dedicated to the ship itself. For example, if a transport has 109 kt cargo capacity, I mentally divide that into a 100 kt shipment plus 9 kt to support the ship and crew.

- In the interest of simplicity, I also assume that the CBT universe has perfected some kind of semi-universal cargo system, similar to today's standardized pallets and ISO containers.

Like Medron, I think that warships mainly use/used their cargo space to carry and support military forces, particularly the leading waves of invasions. I don't think the canon states this, but it makes sense to me that the Star League probably used its warships for such "front line" military transport purposes instead of jumpships; after all, the "rules" protecting jumpships didn't enter play until the Succession Wars, and I know I wouldn't want to risk losing my troops by putting them aboard soft targets.

In my own stories, I have also assumed that warships can be used to securely move certain valuable or highly important cargoes, such as shipments of precious metals, the Davion crown jewels, or "state secret" items like the forbidden personal Remembrance of Nicholas Kerensky, in which it is revealed that "Nikki" was actually a cross dressing gamer who accidentally started the Clans when his/her LARP campaign got out of control. Better yet, imagine this pirate conversation: "Good news and bad news, boss. The good news is that I found out when and where the Fedrats are sending a dropship full of gold. The bad news is that it's being carried on an Avalon." There's you the start of a CBT:RPG campaign...

Anyway, on my own designs, I tend to specialize my ships more than the canon does, so my fighting and heavy transport capabilities are more separated. I usually assume 5% minimum cargo for my own combatant designs, more if it's something like a carrier or assault ship; realistically, that should be enough to support any ship for a significant time, plus some space left over. As I said previously, many people don't realize just how big these numbers really are when you put them in real terms. 7K tons = 100 M1A2 Abrams MBT's, or in CBT terms, a heavy tank regiment. The smallest ship I currently have designed for the Astral Republic's navy is a 420 kt corvette with 22 kt of cargo; even when loaded for endurance, it could still move that whole regiment easily.

Keep the thoughts going, guys.

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Be careful what you wish for. I might let you have it.

I've railed about the huge cargo holds many times. A warship is not a massive cargo hauling ship. And a cargo hold is not a bag of holding. If your warship is carrying more cargo than 10 Mules, you might not be a warship. Food and water for the crew belong in tonnage allocated for that, just as ammunition belongs in a magazine, not in a crate in the hold.

Even worse are those warships with 100k plus cargo holds, almost no shuttles and either no dropships or just one or two. In other words, a huge cargo hold that cannot be loaded or unloaded without taking so long the ship is going to change captains at least once before the hold is filled or emptied. Just empty, useless space. Saying the spare armor is in there won't do, not if you don't have any shuttles built for hauling it out of the hold and making the repairs.

It does not matter how much food, armor, and ammo you have in the hold. If you have no cargo shuttles, and no docking rings, just how are you supposed to get that stuff out of the hold? And what navy have you ever heard of that would build a ship with enough cargo capacity to stock a 50 year supply of spare parts and ammo? It is just wrong to keep seeing warships that carry more tons of cargo than a Monolith with 9 Mules on it. Warship. Cargo ship. There is a difference, but the designers of the Star League never figured that out.

Dead Horse.

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Lyran-ism: You have two cows. One starts a business and becomes insanely rich. The other buys rank in your military and subsequently loses three assault regiments and two worlds to a band of pirates in Locusts.

Crazy idea...could the over-sized cargo holds be akin to the old idea of ballast? Yes I know it's far fetched and cray, but in a crazy way it makes sense...

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Karagin-

Darkness is a friend of mine. Sometimes I have to beat it back, or it would overwhelm me. Shirley Meier

[url]http://karagin12.livejournal.com/[/url]

The Wookiee, he's not wearing any pants!

[img]http://www.heavymetalpro.com/countries/mil-army.gif[/img]

Ballast, if you fly a curve in space and open the ballast-release-hatch a stream of rocks is catapulted in a certain direction. everything there that is not armored will be damaged. if the cloud of rocks is dense enough and wide enough it should be an effective way of (space-)mine-clearing.
on the other Hand: if the Ballast is iron-containing and hot it would severely disturb Radar and heat-sensors. mix a few decoy-radio-Emitters into the stream and you have a nice fake attack-fleet that would look just like a dense Group of advanceing fighters, while the real fighters wait untill the interceptors have made "contact" to the rocks...

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typos and spelling-mistakes are property of the finder. english is not my mother-tongue.

Yeah! 1000 tons of chaff!

Talk about pollution!

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Rick
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[email]rick@heavymetalpro.com[/email] [img]http://www.heavymetalpro.com/countries/flag-us.gif[/img] [img]http://www.heavymetalpro.com/countries/ ... rolina.gif[/img]

* There are 10 types of people in this world. Those who understand binary and those who don't. *

Generally I consider the role of the ship and who has built it to decide what level of cargo it has. Clan ships moving from the clan homeworlds to the innersphere will need more cargo space for food, water, parts and fuel for the crew and their passengers than a ship on permament guard duty at a shipyard.

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hmmm hooom

HeavyMetal Aero does calculate the food and water requirement for the crew. And it adds up to more than you might think. For example, on the TR-3057 McKenna, which has 758 souls aboard, 180 days of food and water weigh 682.5 metric tons. That's 5 kg of food and water per day per person (and I'm sure that's in the rules somewhere - I didn't make it up). 180 days doesn't seem excessive, and 5 kg (11 pounds) per day seems fairly reasonable. That's a gallon of water plus about 2.7 pounds of food. And that would be food weight prior to preparation, so that seems fairly reasonable too.

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Rick
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[email]rick@heavymetalpro.com[/email] [img]http://www.heavymetalpro.com/countries/flag-us.gif[/img] [img]http://www.heavymetalpro.com/countries/ ... rolina.gif[/img]

* There are 10 types of people in this world. Those who understand binary and those who don't. *

Oh, I should mention that, at least in HMAero, the tons for food and water are not considered "cargo", but are listed separately.

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Rick
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[email]rick@heavymetalpro.com[/email] [img]http://www.heavymetalpro.com/countries/flag-us.gif[/img] [img]http://www.heavymetalpro.com/countries/ ... rolina.gif[/img]

* There are 10 types of people in this world. Those who understand binary and those who don't. *

thats the water that is used up, most water Needs for showering drinking cooking etc is collected, cleaned and used again( yes that means Urine and feaces also, it is possible to take water in virtualy any form and make it drinkable again)

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typos and spelling-mistakes are property of the finder. english is not my mother-tongue.

HM Aero does have rules for the food. But I've been working my way through the 3057 revised, doing reviews. I'm into the Clan warships now and I have yet to see even one dropship or jumpship in HM Aero that included food and water for the crew. It must all be in the cargo hold.

And since it's me. I would devote some of the cargo hold to a permanent water tank. Sure you can reuse that water. But a steady stream of filtered pee does not a happy crew make. Filter that water all you want, they still know they pooped in it. Hmm, so how many tons of filtered and frozen poo does a warship have in the cargo hold? Given the size of those holds.... that's a lot of poo.

Go ahead, just imagine the cargo hold of an SLDF Potemkin. Hey, you could grow potatoes on Mars with that.

And since water is also fuel, having permanent water tanks as part of the cargo hold instead of just calling it cargo means your ship will have something to refuel the dropships and fighters with. Especially the Kuan Ti. That thing launches and does a doughnut around the ship and redocks and it needs refueling.

You know, in Star Trek they say a lot of food synthesizers and synthehol drinks. But I don't recall them ever saying anything about what happens when Picard flushes the toilet. "Tea, Earl Grey."

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Lyran-ism: You have two cows. One starts a business and becomes insanely rich. The other buys rank in your military and subsequently loses three assault regiments and two worlds to a band of pirates in Locusts.

U mean "tea, Earl Grey, HOT" or is that "Pee, slightly stale, Lukewarm"

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typos and spelling-mistakes are property of the finder. english is not my mother-tongue.

If you think about it, most of the old battlewagons we have stats for were designed by the Hegemony or the Star League.

Their mission was to fly the flag and make the Star League look good...so I've always figured they brought Cool Stuff with them to all their ports of call...

And they had enough room in their holds to carry supplies in case of emergencies...

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Medron Pryde - The Great and Terrible
[img]http://faileas.greywolf.googlepages.com/WOTD.png[/img]
[url=http://www.pryderockindustries.com]P.R.I.[/url] - The home of BattleTech programs and files
"I'm gonna Tea Party like its 1776." - Medron Pryde
Who is John Galt?

I suppose the appropriate cargo tonnage depends on how large your army is in the Periphery, 10 to 20 jumps away from the core of the Star League.

From the introduction of the WarShip in 2300, Terran-dominated empires in BT have suffered from the bottleneck of interstellar shipping - an Invader with three of the most common cargo DropShip, the Mule, is a pale shadow of a Maersk Triple E. Meanwhile, the Hegemony and its pet Star League tended to fight opponents with only a small percentage of their WarShips. If you look at the 2765 Field Reports, you'll see that the Houses' fleets at the peak of their strengths were tiny compared to the pre-Civil War SLDF fleet.

Accordingly, for the 2300 - 2800 period when WarShips were common, the ships were much more likely going to deliver mail, fuel, and ammo to garrisons than to get into brawling broadside battles with other WarShips. I mean, there were whole generations where WarShips didn't fight another WarShip. (Sort of like today: the USS Constitution is the last active US ship to sink another warship.) They probably did a lot of freight hauling for civilians, too. 100,000 tons will feed only 274,000 people for a year, and there were a lot of Periphery planets with populations in the millions entirely dependent on outside support. That's why so many died when the Succession Wars began.

New, 3050+ Inner Sphere WarShip designs tend to have much less cargo tonnage than their SLDF predecessors, but they were built in a different age to fight a different foe.

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Mike Miller, Materials Engineer

"Woo, that was bracing! They don't like it when you shoot at them. I worked that out myself." --Mal, Firefly

"Going bonkers from EI or DNI is pushing it. I mean how many Crusaders or Super Wobbies are sane to begin with...." --RockJock01

Shades of Grey, when i designed spacecraft years ago, i would devote modifiable cargo bays that could be used for recreation (basically 1% of spacecraft's total tonnage)

u mean that the Crew could use empty cargo-space for sports? when all the stuff in hold 35-a is used up they fold down the basketball-baskets and Play 0-G BBALL?
or small Goals are installed to Play iceless-hockey.
somewhat bigger Goals for Handball or(with the respective size) Soccer.
i have no idea how a 0-G touchdown would look, rulewise, but space-Football should also be an idea

in 3-D 0-G Tennis there could be marks on all 4 sides of a room, so you could Play the ball over all sides( a bit like in "Real-Tennis")

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typos and spelling-mistakes are property of the finder. english is not my mother-tongue.

Saying that these huge cargo holds were used to support colonies and such would be one good way to get around those huge holds being on a warship. But for that to work, that ship must be able to load and unload that hold quickly and efficiently. And almost all such ships in the canon simply can't do it. They don't have a flock of cargo shuttles, they have only 1 or 2 docking rings and more often zero docking rings. And no colony world in the periphery or wherever is going to have an orbital space station huge enough to dock massive warships directly to unload them of 100,000 plus tons of cargo. Especially since the canon makes little to no mention of stations like that.

And the hell of it is that this, like many another flaw, could have been so easily fixed in the 3057 revised. Just take a small slice of that huge hold and put it into a couple of docking rings, a squadron of cargo shuttles, etc. On most of these ships the loss of cargo space won't even be noticeable and it would fix so much that is wrong.

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Lyran-ism: You have two cows. One starts a business and becomes insanely rich. The other buys rank in your military and subsequently loses three assault regiments and two worlds to a band of pirates in Locusts.

The "docking collars" are for hyperspace travel.

You can use other hatches and doors for transferring cargo.

I see is as very normal that any colony would have lots of orbit to ground landing craft that could easily fly up, dock, fill themselves up, and go back down.

The WarShip would bring a handful of its own of course, but a planet should be able to have dozens or more small cargo shuttles with ease.

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Medron Pryde - The Great and Terrible
[img]http://faileas.greywolf.googlepages.com/WOTD.png[/img]
[url=http://www.pryderockindustries.com]P.R.I.[/url] - The home of BattleTech programs and files
"I'm gonna Tea Party like its 1776." - Medron Pryde
Who is John Galt?

I was gonna say, the usual US Navy allowance for fresh water production is 35 gallons per person per day. That assumes drinking, food prep, showering, and other personnel-related water use. The toilets use salt water, so they're not part of the equation.

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Be careful what you wish for. I might let you have it.

I assume that the cargo bays of modern jump-capable ships are fully modular, using an intermodal container type system to configure whatever you need.

Got a bunch of troops or passengers that need transport? Insert an appropriate number of berthing containers, along with some support containers containing galleys, gyms and rec rooms, showers and the like, to create a connected "stack up" in the cargo bay. That in turn can be connected to the rest of the ship, allowing your passengers access to the grav deck and other regular facilities. All that "stuff" that people need is why steerage passengers take up five tons per person, and 2nd and 1st class take up even more. Whether such personnel carrying space is built into the ship or done modularly in the cargo bay, makes no difference to the game on the table, so apply the KISS rule accordingly.

Disaster relief op? Stack up some people containers as above for relief workers and security forces, and load up all your containerized field hospitals, field kitchens, water plants, and so forth. And supplies. Lots of medical supplies, rescue equipment, food, basic clothing (I imagine a few ISO containers full of various sizes of shoes, underwear, coveralls, and foul weather gear; we're trying to help people survive, not make a fashion statement) and other basic needed stuff.

That's just two examples. I'm sure y'all can think of more.

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Be careful what you wish for. I might let you have it.

That's how my Astral Republic does it, and I assume how any warship lacking shuttles and dropships must work. Dirt-based dropships and shuttles can dock to the cargo bay doors to load and unload. They just can't travel with the ship, since that would require either room to carry them inside either in bays or on docking collars or even as cargo; I'm sure most shuttles or fighters and even some of the smaller dropships can fit inside those big cargo bays. In fact, a couple of little Vampires hiding inside a "cargo" ship could make for an interesting stealth op.

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Be careful what you wish for. I might let you have it.

What if they built a ship that carried the dropships to their target, and just let them go without needing to worry about picking them back up?

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Karagin-

Darkness is a friend of mine. Sometimes I have to beat it back, or it would overwhelm me. Shirley Meier

[url]http://karagin12.livejournal.com/[/url]

The Wookiee, he's not wearing any pants!

[img]http://www.heavymetalpro.com/countries/mil-army.gif[/img]

yeah, cobayashimaru, characters could play sports like pizza pie volleyball, and yeah, i had a gravity deck on each large spacecraft for them