[FT] Debris Reef Harbour [LONG]

I was going through NIFT's Full Thrust Weapons & Defences Archive and
came upon the entries for Gravitic Shepherd Buoy & Battle Debris.  With
a debris field supported by a Gravitic Shepherd Buoy, to my mind, being
a much more reliable area denial weapon than the mines first presented
in FT rules book, I came up with an idea for a space construct to be
encountered during a campaign game - a means of protecting civilian
ships at anchor around a world, and a mothballed reserve fleet from
hit-&-run raids - A Debris Reef Harbour.  

A Debris Reef Harbour will usually be encountered in systems that border
potentially hostile intersellar nations...

Systems that are home to a nation's reserve fleet...

And systems that enjoy extensive asteroid mining operations.  

To set up a debris reef harbour in a play area, you will need an
unopened soda can (or small jar or water glass or tin can or cylindrical
object) with a base that is the game scale equivalent of at least 4MU in
circumference...

some adhesive tape and some string that is a MINIMUM of 16MU in length.  

Attach the length of string to the side of the can with tape near its
base and place the can on the play area where the center of the harbour
should be, with the side with attached string facing where you want the
harbour entrance to be.  

Gently pull the string taut, and place a marker where the string ends.	

Now, without dragging the can from its central position or allowing it
rotate with the motion, move the end of the taut string 2MU either
clockwise or counterclockwise [your choice] and place another marker.  

Repeat again & again, until you've laid markers in a circle around the
can, with the string being wrapped around the base of the can.	Continue
until the string has been wrapped around the base of the can AT LEAST
TWICE.	

When you remove the can from the play area, and you did everything
correctly, you will find a spiral line of markers running in a shrinking
circle.  This is the template for where you are to set up gravitic
shepherd bouys that support the debris reef.  

In game terms, the debris reef is set up by gathering, into a
quick-release net, the game scale equivalent of at least 40 ship mass of
derelict starship parts and/or asteroid mining waste, with a
time-activated gravitic shepherd bouy in the center.  The net is towed
to the proper location in space, decelerated to 0mu velocity, and the
contents released.  When the debris has drifted out to 2mu, the bouy
activates and locks the debris in position.  

The completed reef will be a 6-8mu wide debris asteroid belt, with a 2mu
wide open channel running the circumference of it.  The channel allows
for the passage of shipping into the harbour without damage from debris
strikes.  The body of the reef is intended as a defence against salvo
missles fired from outside the harbour entrance.  A salvo missle group
trying to penetrate a debris field rolls a number of dice equal to the
DENSITY of the field [4-5=1 hit, 6=2hits+reroll] with each hit
destroying a missle for every FULL 6mu of range.  So, an ER salvo firing
through a density 6 field has a cat's chance in Hell of doing damage to
anything on the other side!  And trying to fire the salvo through the
channel to the harbour within will fail because the transverse length of
the channel exceeds 48 mu, if using the minimum harbour radius of 16 mu.
(At last, a practical use for the concept of PI)  

But in order to make sure that density of the WHOLE reef is uniform, the
density of the debris field groups will have to TAPER, so that attacks
don't just occur at the harbour entrance, where there is only one line
of debris fields, instead of the opposite side, where there are two.  

When setting the density of the debris fields, start at the channel
entrance with a density of 2.  For the first 3rd of the way down the
reef, begin to increase the density to 6-8.  The second 3rd of the way
should hold at 6-8.  The final 3rd should taper back to density 2 at the
end of the channel.  

However, MT missles escorted by fighter groups flying through the
harbour channel still pose a real threat to shipping in the harbour.
That's where another system I found at NIFT's FTWeapDefArchive is needed
- the Area Defence System - found in INTERCEPTION.  Mounted on STL
barges, spaced 6 mu apart, all along the inside wall of the inner half
of the reef, they produce overlaping arcs of fire, forcing hostile
fighters to run a gantlet of defence fire the length of the harbour
channel.  And with a harbour channel that is at least 48 mu in length,
even a fast fighter group starting its turn at the mouth of the harbour
channel, and using its second movement, will still be in the channel at
the end of the turn, vulnerable to overlapping defence fire.  

The Debris Reef Harbour isn't a perfect defence against attacks to
anchored shipping.  Long-range beam & pulse torpedo fire can still
penetrate the reef.  The channel is a shallow curve that doesn't take
into account the 12-sided facings involved in writing movement orders,
so movement through the channel can only safely be negotiated at a very
slow speed [1-2mu per turn], so there needs to be a defending force
outside the harbour if a large fleet attacks.  And though a density 8
debris field is a deadly hazard to small ships, a battleship or
dreadnought can plow through at low speed without even taking a
threshold check.  

Even though a debris reef harbour is vulnerable to attacks by big ships
with big guns & pulse torps, it does provide a excellent defence against
hit-&-run raids mounted by fighters and fast small craft firig salvo
missles.  And even though it takes a ship in excess of 48 turns just to
enter the harbour, civilian shipping would generally feel more
comfortable protected by the reef than anchor naked against the
fathomless void.  

On its own, a debris reef harbour has little effect on a potential
battle ground other than as a large hazard to movement, but since a
debris reef will usually only be encountered in systems that have major
trading ports and naval bases that support the reserve fleet, their
presence will indicate that the battle is not just another random naval
engagement, but a major operation that will determine the fate of a
strategic objective.  

I invite your comments.  

JBrewer@webtv.net  

"Always strive to be a good person.  If you can't do that, at least
strive to be someone other than an asshole."