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Author Topic: Ratchet Jumpyard  (Read 416 times)

Lagrange

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Ratchet Jumpyard
« on: 29 November 2022, 12:12:58 »
I've been debating the necessity and desirability of a pressurized yardship in discussion with Retry.  Is costing twice as much worth an extra -2 modifier?  With the era modifiers (up to +3), it looks like the answer is a clear "yes". 

The driving use case is given by KF-drive repair in difficult eras like the 4th succession war.  You really want to repair rather than replace a KF-drive since they cost (say) 300M c-bills.  KF-drive repair may require a jump-capable yard.  The repair modifier however is a at +5.  With an unpressurized repair bay (-3 modifier) taking x4 time (-3 modifier for 40 days) in a difficult era (+3 modifier), you are still looking at repair roll of 8 for a regular team, 7 with a veteran team, and 6 with an elite team which has a very high 6.8% failure probability or an expected 20M cost every time a KF-drive is damaged.  Even if the era modifier is only +2 (which is more common), the expected cost is still 6M.   Since a jump mobile pressurized repair bays costs an extra ~900M c-bills, the investment pays off in 1 or 2 decades.  As a side effect, every other repair (they are _all_ easier) can typically be done faster.

Code: [Select]
Class/Model/Name: Ratchet jumpyard
Tech: Inner Sphere
Ship Cost: $1,818,051,250.00
Magazine Cost: $0.00
BV2: 1,253

Mass: 300,000
K-F Drive System: Standard
Power Plant: Station-Keeping Drive
Safe Thrust:
Maximum Thrust: 0
Armor Type: Standard
Armament:
None

Class/Model/Name: Ratchet jumpyard
Mass: 300,000

Equipment: Mass
Drive: 3,600.00
Thrust
Safe:
Maximum: 0
Controls: 750.00
K-F Hyperdrive: Standard (6 Integrity) 285,000.00
Jump Sail: (5 Integrity) 70.00
Structural Integrity: 1 2,000.00
Total Heat Sinks: 129 Single
Fuel & Fuel Pumps: 500 points 204.00
Fire Control Computers: 0.00
Armor: 66 pts Standard 166.00
Fore: 11
Fore-Left/Right: 11/11
Aft-Left/Right: 11/11
Aft: 11

Dropship Capacity: 0 0.00
Grav Decks:
Small: 1 50.00
Medium: 0.00
Large: 0.00
Escape Pods: 0.00
Life Boats: 0.00

Crew And Passengers:
4 Officers in 1st Class Quarters 40.00
17 Crew in 2nd Class Quarters 119.00
0 Gunners and Others in 2nd Class Quarters 0.00
285 Bay Personnel 0.00
1st Class Passengers 0.00
2nd Class Passengers 0.00
Steerage Passengers 0.00

# Weapons Loc Heat Damage Range Mass
None

Ammo Rounds Mass
None

Equipment Mass
100000 ton pressurized repair bay  7500 tons

The Ratchet is typically paired with a large space station like the Way station which supports quarters and storage for a large repair crew.  It is used in 4 modes:

  • Sedentary Repair Units capable of jump transport move to it for repair, replacement, and maintenance.  The Ratchet is capable of handling any dropship in this fashion, as well in-system stations like the Sloth, and smaller transiting jumpships like the Voyager.
  • Jump Circuit Repair The Ratchet can slowly work it's way around the circuit to handle whatever repair/replacement/maintenance needs occur for vessels interacting with the circuit.  To keep it's support, the repair crews uses the 10 infantry bays (supporting 300 people) for about 2 days during a jump, the Ratchet first loads the support station, jumps, and then unloads the support station.   (I'd estimate the time to load an unload as twice dropshuttle time, implying ~19 hours each.)
  • Off-circuit Repair.  Particularly when a KF drive is damaged somewhere off-circuit, it's valuable enough to send a Ratchet. When multiple jumps are required to reach a location the Ratchet can accomplish a long sequence of jumps using supplies on the support station.  Between each jump, the crew unloads the support station for access to much more comfortable quarters.
  • Transport.  Sometimes, simply having the ability to move a station through a jump is desirable. This is straightforward: load it up, jump, and unload.  It is actually fairly valuable when the alternative is constructing a new station.

A problem arises: what if the Ratchet itself has KF-drive damage?   For that an expensive (and rare) Ratchet U replaces the 100 kton pressurized repair bay with a 300 kton unpressurized repair bay.  The variations are below.
Code: [Select]
Class/Model/Name: Ratchet U jumpyard
Ship Cost: $2,443,051,250.00

Equipment Mass
300000 ton unpressurized repair bay  7500 tons

Tradeoffs
LF battery or not?  It is possible to add an LF-battery as per here.  It adds 33% to the price and requires increasing the size to 500K tons.  My expectation is that this is not worthwhile---as typical jobs require either 0 or 1 jumps to complete.  It's also not possible to have an unpressurized repair bay capable of maintaining jumpships of the same class with an LF battery.

Maximum capacity 100k tons is an obvious capacity choice since it supports all dropships, a good jumpship, and many stations.  We could go higher to support transport of larger stations, but that seems unnecessary if there are a couple Ratchet-U's available to handle any oversize transport missions.  You might consider going larger if you want to assist in maintaining warships.  However, the logic of wanting a pressurized repair bay still applies and you simply can't create a large pressurized repair bay on a jumpship.

Daryk

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Re: Ratchet Jumpyard
« Reply #1 on: 29 November 2022, 19:25:01 »
In general, -2 on a 2d6 curve is WORTH IT.   :thumbsup:

Retry

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Re: Ratchet Jumpyard
« Reply #2 on: 29 November 2022, 20:38:57 »
Quote
The driving use case is given by KF-drive repair in difficult eras like the 4th succession war.  You really want to repair rather than replace a KF-drive since they cost (say) 300M c-bills.  KF-drive repair may require a jump-capable yard.  The repair modifier however is a at +5.  With an unpressurized repair bay (-3 modifier) taking x4 time (-3 modifier for 40 days) in a difficult era (+3 modifier), you are still looking at repair roll of 8 for a regular team, 7 with a veteran team, and 6 with an elite team which has a very high 6.8% failure probability or an expected 20M cost every time a KF-drive is damaged.  Even if the era modifier is only +2 (which is more common), the expected cost is still 6M.   Since a jump mobile pressurized repair bays costs an extra ~900M c-bills, the investment pays off in 1 or 2 decades.  As a side effect, every other repair (they are _all_ easier) can typically be done faster.
Are these pay-off analysis based solely off the price differences between repairs and replacement or do they also factor in averted economic damages for Jumpships or Dropships suffering from potentially long down-times?

Lagrange

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Re: Ratchet Jumpyard
« Reply #3 on: 29 November 2022, 21:34:47 »
Are these pay-off analysis based solely off the price differences between repairs and replacement or do they also factor in averted economic damages for Jumpships or Dropships suffering from potentially long down-times?
Just repair vs. replacement.

Averted economic damage is a more challenging computation.

 

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