11 May 2021

Duty Cycle

Something that's intended to, realistically, exert some control on the ship-owning Traveller party is the ongoing costs of doing maintenance.

Every year a ship must put in and have annual maintenance performed or a malfunction chance is added to all the major systems.

Jump Drive, Power Plant and Maneuver Drives in particular.

Due to a book-keeping error in my Interstellar Wars campaign with JT and FuzzyGeff caused me to miss the expected duty cycle for the jump drive and the rate at which the good-ship Northern Lights was traveling.

They were jumping at twice the assumed rate of 26 jumps per year.  So they should have been putting in for their annual at six months instead of one year.

This got me to thinking about how many hours the maneuver drive has been running between overhauls.  It only takes a couple of hours to get to (or from) the 100 diameter limit with even a 1g drive.  4 hours per jump.  26 jumps a year.  104 hours between overhauls.

That can't be right since these same maneuver drives are used in system for months or weeks at a time by non-starships just traveling between planets.  Boats need their drives overhauled at the same annual rate as the mostly idle ships' drives.

I'm going to have to do some math.


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    1. I don't have the power to do it. Your best bet is to copy-paste it to the correct post. When you do, I will delete them from this post.

  3. There's some things I don't like about Traveller. Like... some of the maintenance things. They seem to be based on either handwavium or maybe Victorian-era steam ships, but VESSes actually don't spend all that much time in maintenance as maintenance is done while in motion.

    Then there's starship hulls, which if you use Striker the hulls of even the cheapest in-system boat are armored better than most AFVs. Which, if one is using surface ships as an example, is clearly wrong. Especially when ship-missiles and ship-lasers don't scratch the same AFVs as easily as they do scratch other ships. Sum-ting-wong there.

    Got into this argument on CotI several times. It should be the other way around. With a standard ship hull being a double hull or at least a single skin with a flexible spray liner or something. And except for ribbing and framework, actual hull plates shouldn't be something that you can't shoot through (friend's grandfather, in the Navy, was regularly assigned to go sink vessels using... M1 Garands. Blow holes along the waterline and just let the damn thing sink. Confirmed this story by asking someone else, who also said, short of real armor plate, a .30-06 would go through the hull plate of most post-WWII ships. (the steel got better and thicker as ships got newer and larger, but still, a determined idiot with a good rifle and the proper ammo can still sink many a ship at sea, supposedly, maybe, maybe not.))

    But, still, especially for lower tech levels 9-10-11, ships shouldn't be armor plated wunderships, if one looks at current water ships.

    1. Those inconsistencies between games set in Traveller is why I embrace GURPS. DR is DR is DR. Damage listed for a ship's gun is expressed in the same notation as a tank.

      The super thick armor of a Traveller ship is because Marc W Miller and Loren K Wiseman didn't notice that any ship with a week of acceleration higher than local surface gravity could soft land without any friction from the air. They had aerobraking as normal, and the streamlining requirement to land on a planet with an atmosphere.

      GURPS Traveller gives a DR of 100 for the Type A Free Trader (which is what you need for a non-ablative aerobrake reentry) and DR 25,000 for the front slope of an Intrepid Grav Tank. A TL 10 250 MJ ships laser will do 5dx50(2) (875 average, halve DR against it) the 2.3 GJ heavy fusion gun on the tank does 6dx650 damage (13,650 average damage).

      A commercial starship in GT is not going to hurt even the roof armor of the cupola on the tank (DR 5,000). The cupola mounted 4mm VRF Gauss Gun has a decent chance of penetrating a ships hull with a 6dx3(2) and stupid high RoF of 100 per second.

    2. Oh and add in the contragrav tech and you don't even need a drive to exceed local gravity to launch or soft land!


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