Cray
06/04/14 07:21 PM
67.8.171.23
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Quote:
Karagin writes:
Once again let me explain it, this is NOT a glorified jumpship. The idea here is to NOT have it ferry around drops ships,
Oh, okay, cool. I apologize, I only skimmed the stats and jumped to the recent posts, not all the old posts. I only read in threaded mode.
I fully approve of the design goal. I've made small ships with that goal, too.
So...
Alright, if this is to be a viable cargo merchant ship, then you should at least aim to compete with existing ships on a price and cargo basis. That's going to be challenging.
First, your listed price is incorrect due to recent rules changes. To address a problem with older pricing rules that allowed WarShips (even 2.5-megaton giants) to be cheaper than high-end DropShips, Strategic Operations added in a new tonnage-related cost, the KF support systems:
20,000,000 x (50 + Unit Tonnage รท 10,000), and that gets multiplied by the final cost multiplier (x2) like everything else.
To save you some time, that's an extra 2.4 billion, so you've got a total of about 4.2 billion. 4.2 billion buys a lot of DropShips and conventional JumpShips, so the bar is set high on performance. And while you don't have to carry it, you're going to need DropShips at the origin and destination to deliver cargo to the ground since, within the rules, WarShips can't land. (Obviously, you can wave that in a home game.)
Second, your competition generally consists of Merchant and Invader JumpShips hauling Buccaneer or Mule-class DropShips, the most common civilian freight haulers. (Obviously, this excludes big DropShips like the rare Mammoth and Behemoth). At the small end, a Merchant and two Buccaneers can deliver about 4,000 tons of cargo, while at the upper end an Invader can deliver 3 Mules with 25,500 tons of cargo.
The Merchant is now about 530,000,000CB with its KF support systems (Tonnage x 1,000 x 1.25 for conventional JumpShips), while a pair of Buccaneers is 220,000,000CB. The Invader is now about 670,000,000CB, while 3 Mules is 480,000,000CB. Competitors will be able by multiples of those JumpShip-DropShip combos and haul a lot more cargo than you can, at the same delivery rates, so you'll either want a huge cargo increase or to find some niche cargo.
Next, options for improving your cargo capacity. If they fit your concept, feel free to use them. If not, that's cool. It's your ship.
1) Strip minor items. Among them:
You've got crazy large amounts of fuel. Crazy, over 600 burn-days of fuel. The typical round trip to and from a destination planet is only about 30 to 40 burn-days. Most military WarShips rarely have more than 150 burn-days, so you can - if you want - free up 9,000 or more tons from that.
Each of the 300-meter gravdecks give you about a linear kilometer of corridor space for quarters, rec rooms, ball courts, etc., and that's assuming you only have one corridor and one floor per gravdeck. I generally approve of big gravdecks because small, fast-spinning ones tend to nauseate occupants and a 225m diameter is the magical number to begin minimizing that and maintain 1G. However, you only have about 200 passengers and crew who only need less than half of one of those gravdecks. So, I'd ditch all the 300-meter decks and one of the 250-meter decks to free up 2100 tons.
If you're not planning to use this as a military transport, 100 marines is a lot of overkill. 10 security personnel is plenty, so that'd be +450 tons.
A merchant ship is probably twitchy about recurring costs like salaries and ammunition, which is sort of silly when you compare the payments on a 4.2-billion CB ship, but merchants seem to think that way. Of those costs, ammo is quite high on your ship: a ton of LRM ammo is as expensive as several years' salary for a typical crewmen. If you ditched the LRMs and Gauss Rifles, you'd save 257 tons directly and 28 more tons by eliminating 4 gunners: 285 tons. That'd leave you with pretty excellent energy weapon coverage.
Typical TRO formatting would not list food & water separate of the regular cargo, so that's 112.5 tons you could shift to cargo. (Obviously, the crew would still need to eat, but you'd be more flexible in how much could be assigned.)
All those little tweaks get you about 12,000 extra tons of cargo. That's a payload large enough to be useful.
2) Strip major items: the engines
Having higher than 2/3 thrust on a civilian spaceship that will never land is something that will only be useful for minutes in a ships' decades-long life unless it gets into a war zone and gets chased. It is not practical to use 5/8 thrust for days on end for two reasons:
a) High acceleration cuts travel times a surprisingly small amount. The basic equation for distance-vs-acceleration (available from your handy physics textbook, wikipedia, DropShips & JumpShips, or Strategic Operations) shows that travel time is related to the square root of acceleration. If you double the acceleration from the standard 1G to 2Gs, you don't cut travel time in half. Instead, you cut it by 1.414 (the square root of 2). You need to go to 4Gs to cut transit times in half. Your ship can do that by cranking at max Overthrust the whole time, but that leads to the next problem...
b) You'll kill the crew, or at least endanger their health. You could get away with days at 1.5Gs (3 thrust) with a healthy, young crew, but the human heart begins having trouble lifting blood against 2-3Gs. Keeping the crew in acceleration couches for days at 2Gs just begs for bed sores.
c) You can't use the engines to push the ship through a star system and recharge at the same time, and the jump sail can't be deployed while you're zipping along 1G+. That means you need to stop and recharge for 1 week in each system, annihilating any regular, peacetime benefits from traveling at high Gs.
Conclusion: shrink the engines. 2/3 is plenty for a merchant freight, or maybe 3/5 if you want a chance to outrun pirate ships. That would free up 12,000 to 18,000 tons, if you're interested.
3) Major design change: make it bigger.
Ultimately, WarShips get most efficient at hauling freight at their largest possible size. You have the minimum crew size, minimum proportional fuel requirements, minimum proportional structural and secondary equipment masses, and largest cargo capacity per jump. Meanwhile, 100,000-ton ships will have the largest proportional mass of non-cargo items.
Since you probably weren't interested in ultra-mega-2.5-million ton freighters if you built a 100,000-ton ship, then modest jumps to 150,000 or 200,000-ton designs will open tens of thousands of tons while keeping the current items present.
Or not. It's your baby.
Mike Miller, Materials Engineer
Disclaimer: Anything stated in this post is unofficial and non-canon unless directly quoted from a published book. Random internet musings of a BattleTech writer are not canon.
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Karagin
06/04/14 08:55 PM
70.118.139.48
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And again Donkey you missed it, it's not set in stone, it's a concept, it's something to add flavor and variety to the game. It's not meant to be the end all of things, just another look at stuff. Yes it can be refined as Cray posted and it can be improved on a lot.
Karagin
Given time and plenty of paper, a philosopher can prove anything.
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Karagin
06/04/14 09:29 PM
70.118.139.48
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Cray, interesting ideas and suggestions, I will play around with somethings, like I stated it's not a finished concept, it is an idea, and it does need some fine tuning.
Karagin
Given time and plenty of paper, a philosopher can prove anything.
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ghostrider
06/05/14 07:08 AM
24.30.130.52
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You would not have to just use the ship to bring in cargo. You could use it as a escort for a fleet. If it would actually engage the enemy that might try to hijack the fleet.
I do not see where it says they would not engage entirely. Only something bigger then itself. So it would be more then enough for a pirate attack, maybe 2 drops ships or so. Granted, if they have a fighter carrier, or multiple assault ships then you may have issues. Then again if they do, you would lose the fleet without an issue.
Having this one as an escort would give you a chance.
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Karagin
06/05/14 05:55 PM
70.118.139.48
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IT is not a warship per say.
Karagin
Given time and plenty of paper, a philosopher can prove anything.
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Retry
06/06/14 03:01 PM
76.7.236.208
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I have always found it curious that the only thing that distinguishes a jumpship from a warship is, technically, the compact drive engine thing. You can technically make a "warship" with the upgraded drive, dump all the tonnage into armor and cargo and dropship ports and basically make a super jumpship that's just called a warship.
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Cray
06/07/14 02:41 PM
67.8.171.23
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Quote:
Retry writes:
I have always found it curious that the only thing that distinguishes a jumpship from a warship is, technically, the compact drive engine thing. You can technically make a "warship" with the upgraded drive, dump all the tonnage into armor and cargo and dropship ports and basically make a super jumpship that's just called a warship.
Well, rules-wise there are other issues. At a minimum, WarShips have different fusion engines, bridge masses, and structural masses than JumpShips. It's the difference between a river barge and an ocean-going vessel.
But, yes, if you install a compact core it gets automatically dubbed a "WarShip" even if it has no guns.
Mike Miller, Materials Engineer
Disclaimer: Anything stated in this post is unofficial and non-canon unless directly quoted from a published book. Random internet musings of a BattleTech writer are not canon.
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