Re: ship maintainance questions (Td#356)

Date: Mon, 24 Jul 95 01:46:05 -0400
From: Derek Wildstar <wildstar@qrc.com>
Subject: Re: ship maintainance questions (Td#356)

rhunt@med.unc.edu (Rick Hunt) asks:
> What is the role of wear value in starship maintainance?  Earlier in the
> chapter, the rules say that you roll for breakdown every 8 hours, but this
> seems a little extreme for a ship in jump.  Even a ship with a wear of 1
> and a good engineer will never last a week in jump.

You're exactly right - the rules, as written, will have practically every
starship with wear value of 1 or more kill their occupants on the first
jump.  You should treat those rules as only applying to cross-country
trips with military equipment in a post-nuclear-holocaust 21st century Earth
setting (in other words, the wear rules are holdovers from Twilight:2000
that were just dropped into T:TNE and applied to starships without actually
thinking about them, let alone actually playtesting them).


For starships (and other "high-reliability" equipment, as determined by the
Referee; all spacecraft are automatically "high-reliability"), rolls against
the wear number should be made no more often than once per week.

If you're using the "generic" system (one wear value for the entire
starship), roll once per week, determine the system that malfunctions,
(or potentially malfunctions) and implement the incedent at some
appropriate point during the week.

If you're using the "detailed" system (wear values for individual systems),
make the roll the first time the system is used during the week. 


It's also worth noting that the "detailed" system is not equivalent to the
"generic" system.  A wear-5 starship would have a 50% chance of a potential
breakdown each week (affecting one system).  Broken into three wear-5
systems, the ship would have a 87.5% chance of at least one potential
breakdown a week, approximately eqiuvalent to wear-9.

To convert from "generic" to "detailed" (or back again), you can use the
following table and procedure:

Wear	Chance		To determine the composite (generic system) wear
0	1.0		value of a ship that has multiple systems, each
1	0.9		with it's own wear value, determine the "chance"
2	0.8		corresponding to each wear value, and multiply
3	0.7		them together.  Subtract the result from one,
4	0.6		then multiply by 10 and round to the nearest
5	0.5		integer.  This result is the composite wear value
6	0.4		of all of the systems.
7	0.3
8	0.2		Wear = 10 * (1 - Chance1 * Chance2 * Chance3 ...)
9	0.1	

For most ships, it's reasonable to assign wear values by trial-and-error,
repeating until the composite value is correct.

Example: A ship using the generic system has a wear value of 3.  The referee
would like to break this up into four "systems" (maneuver/power, jump, life
support, and electronics).  As an initial guess, he assigns wear values of
2, 1, 0, and 1 respectively.  To calculate, .8 * .9 * .9 * 1.0 = 0.648;
and 10 * (1-.648) = 3.52, which rounds to 4; a bit high.  Setting all the
wear values to 1 results in 3.439, which rounds down to 3.

> Does maintainance cost money?  Or does the crew just walk around
> tightening screws and pushing buttons?

Right.  "Maintainance" costs (hoses, fan belts, and the occasional oil and
oil filter change) are presumably included in the operating costs of the
starship.  Again, the maintainance rules are lifted from T2k, where purchase
of such maintainance items is impossible, and the characters are assumed to
jury-rig, make do, and scrounge.

In Traveller, presumably the cost of any maintainance parts is included in
the day-to-day operating costs of the ship (life support costs, annual
maintainance costs, and so on).

> Does the wear value have any effect on time or money?

Well, you generally spend more time going around tightening screws and
pushing buttons on a high-wear ship, in an attempt to gain favorable
modifiers if there ever is a potential breakdown.