Fast X-Boat

A thread of 2 messages, 4 November 1991 to 6 November 1991, in the order they were sent.

#3065 Fast X-Boat

Pauli · 4 November 1991

hi,

	The Fast X-Boat, or how to break the jump-6 barrier!


CraftID:  Fast X-Boat, Type XZ TL=F (High Stellar), MCr245.994
Hull:     90/225, Disp=100, Config=1AF, Armour=40G
	  Unloaded=588.304 tons, Loaded=1036.357 tons
Power:    1/2, Fusion=252Mw, Duration=1015.87/3047.62 (6 weeks full output)
Loco:     2/4, Maneuver=1, 2/4, Jump=1,
	  NOE=190, Cruise=900, Top=1200
	  Agility=0
Commo:    3xRadio=System, 2xLaser=System, 2xMaser=System, Meson=Far Orbit
Sensors:  2xPassive EMS=Interstellar, 2xActive EMS=Far Orbit
	  2xDensitometer=HighPen/1km, 2xNeutrino=10kw
	  ActObjScan=Rout, ActObjPin=Rout,
	  PasObjScan=RoutRout, PasObjPin=Rout,
	  PasEngScan=Simp, PasEngPin=Rout
Def:      DefDm=+10
Control:  3xComputer=9fib, Panel=Holographic linkedx11, Special=Heads-up Display
	  Environ=basic env, basic ls, extend ls, grav plates, inertial comp
Accom:    Crew=1, Stateroom=1
Other:    Cargo=410.743kL, Fuel=533kL, FuelScoops
	  ObjSize=Average, EmLevel=none (EMM)

This ship is an experimental fast courier.  The ship is fully supplied and it
then induces a mis-jump.  Once the ship comes out of jump space, it attempts to
identify its current location and to then travel to the nearest system.
Because of the somewhat random direction of travel, this kind of ship is only
used for news of a general nature, often several such ships will launch at the
same time hoping to reach distinct destinations. The ship carries enough fuel
for three seperate jump-1's and six weeks of power plant fuel.  All computers
and controls have ECP backing.  The reason for carrying the three jump-1s is
to increase the survival chance of the ship to a decent level.

As an aside, the probability of the ship surviving each launch is quite
impressive.  Assume the following represents a portion of a hex grid:

              l a b
             k 5 6 c
            j 4 S 1 d
	     i 3 2 e
              h g f

After a mis-jump assume the ship is located at the S in the above diagram.
Since the density of systems in the Traveller universe is about 0.5, this means
that there is a fifty percent chance of already being at a system. If you are
not at a system there is a 63 in 64 chance that you are one hex from a system
(hexes 1..6 in the diagram).  If that fails, there is a 4095 in 4096 chance
that you are two hexes from a system (hexes a..l).  If both of those fail, the
ship can induce a second mis-jump which will move you to a new S hex, which
again has a fifty percent chance of being empty and the six hexes around again
give a 63 in 64 chance of being able to jump there safely.  If this fails the
ship can induce a third and final mis-jump with a fifty percent survival
chance.  Working out the above figures leads to the final survival chance of:

	 -1 -6 -12 -1 -6 -1    -27            -9
	2. 2 .2  .2 .2 .2   = 2    = 7.45 * 10

So you have a 7.45E-9 chance of not locating a system, this gives a
0.999999992549 probability of finding a system (99.9999992549%). I think that
this is slightly better than flying on an airplane, and a lot better than drive
around town.

As for the distance travelled: A mis-jump goes 6d6 hexes in a random direction.
6d6 gives an average distance of (6*3.5=21 hexes) which is quite good.  Most of
the time the destination will be within on hex of a system and this makes the
travel time about two weeks (average of jump-10.5).  If the second jump is
required, this still averages jump-7.  The only problem is that the direction
is not very well known.

Needless to say, this ship isn't used very heavily around the low density
regions of space.  You'd have to be totally insane (or a Vagyr :-) to attempt
this kind of travel near the rift.  Even travelling normally, if the first
mis-jump doesn't land you near any systems then you've got some real problems
for your nerves as you induce the second mis-jump (1 in 128 failure chance) and
if that fails then you'll be a nervous wreck with an even survival chance! Of
course, having a robot pilot the thing saves a lot of suffering and so on.



        						Pauli

Paul Dale               | Internet/CSnet:            [email removed]
Dept of Computer Science| Bitnet:       [email removed]
Uni of Queensland       | JANET:           [email removed]
Australia, 4072         | EAN:                          [email removed]
                        | UUCP:           [email removed]
f4e6g4Qh4++             | JUNET:                     [email removed]

#3084 Re: Fast X Boat

Pauli · 6 November 1991 · reply to #3065

hi,

I designed this ship mostly to see how effectively such a thing could
be done.  It would be a very popular thing to build and it probably
wouldn't be very cost effective due to the number of ships required.


>>As for the distance travelled: A mis-jump goes 6d6 hexes in a random
>>direction. 6d6 gives an average distance of (6*3.5=21 hexes) which
>>is quite good.

>No, it's d6d6 hexes (unless they've changed that in MegaT) so
>the average distance is (3.5*3.5=10.5) hexes.

Oops, I made a slight error here.  However, it isn't that bad.  The mean is
better than 10.5.


Not quite that easy....the mean of a product isn't the product
of the means.  The result you want is:

for 1d6, average is 3.5
for 2d6, average is 7
for 3d6, average is 10.5
for 4d6, average is 14
for 5d6, average is 17.5
for 6d6, average is 21

Summing the averages and dividing by 6 gives: 12.25 hexes average mis-jump
distance.  This is possible because each of the above is equally likely.


>And since you
>will most propably need 2 or 3 jumps to get to somewhere useful,
>two controlled jumps-6 will be preferable.

Most probably you need 2 jumps,  you have an even chance (50%) of getting
somewhere in 1 jump and a 127 in 128 (= 99.2%) of getting somewhere in 2 jumps.
If you put a jump-2 drive in the ship you would have a really good chance of
getting somewhere in 2 jumps.

As seen above, this method is slightly better than two controlled jump-6s
(.25 hexes on average).  The variance is much larger and since this method
of communication requires multiple ships to be launched, you have a pretty
good chance of sending the stuff further.  You also have a nice chance of
sending is less far as well.


>About the safety factor: I thought there were a small, but not
>insignificant, risk that any misjump would slag the engine.

Maybe I'd better include a second engine in the next redesign.



        						Pauli

Paul Dale               | Internet/CSnet:            [email removed]
Dept of Computer Science| Bitnet:       [email removed]
Uni of Queensland       | JANET:           [email removed]
Australia, 4072         | EAN:                          [email removed]
                        | UUCP:           [email removed]
f4e6g4Qh4++             | JUNET:                     [email removed]