by Pieter Thomassen
Seron Thoun class Border Fleet battlecruiser
Name and disposition:
Approximately 400,000 Seron Thoun battlecruisers were commisioned in the
Tirolian Border Fleets and the Tirolian Special Forces.
These ships were built at various locations throughout the Robotech
Mercantile Empire, including the Orbital Shipyards over Fantoma and the
Maldara lunar yards in the Valivarre system, and entered service from
1732 through 1969.
- Ship's crew (1762 Tirolians, 20 Zentraedi),
- Air Group (50 Tirolians, 80 Zentraedi),
- Troops (200 Tirolians, 200 Zentraedi),
- Life support limits are for a full combat complement and about 50
Zentraedi supernumaries (125,000 Tirolian sized men total).
- Length: 1391 m (main hull).
- Height: 239 m (main hull), 367 m (over all).
- Width : 180 m (main hull), 312 m (over all).
- Mass : 10,950,000 metric tons, operational (typical).
- Fuel Mass: 1,300,000 metric tons, maximum (typical).
- Main power system: Zorrelev-1035-Trafla protoculture-fueled Reflex furnace cluster. The powerplant of a Seron Thoun class vessel
can nominally deliver up to 19.7 Petawatts of power, and can operate for
seventy-five minutes at maximum power before overheat initiates autoshutdown.
- Maneuvering Thrusters (12): fusion-plasma reaction
thruster clusters with steerable nozzles. Located on the port and starboard
top, sides and bottom halfway forward and aft.
- Reaction-mass Thruster (1): Varrelev Weik-12 fusion-plasma reaction thruster with protoculture energizer mounted in the rear
of the ship.
- Secondary Reaction Thruster (1): Varrelev Weik-9
fusion-plasma reaction thruster with protoculture energizer mounted in the
rear of the command citadel.
- Anti-gravity System (1): 18 Rastraz anti-gravity pods.
- Space Fold (1): Nolfantom-proldarlev 874 spacefold.
This system generates a hull-conformal fold.
- Planetary Capabilities: The Seron Thoun-class has
atmospheric capabilities through its reaction thrusters and anti-gravity
system. The hull has sufficient structural strength for the ship to make a
cold landing on it, but the lower bulge will prevent the ship from remaining horizontal
unless a supporting structure is erected.
Note that the ground underneath should be as firm as
possible. The ship will float in an ocean, and this is the preferred landing
Endurance and mobility limits:
- The dry stores endurance was limited to about 2.5 years with a full crew
complement. The extensive recycling installations ensured that only
incidental biomass losses needed to be replenished. Water stores were
recycled almost completely. The hydroponics installations on board provided
the crew with a steady supply of fresh foods.
- The mecha consumables supplies (mainly missiles) were extensive, and could
sustain continuous combat operations for over thirty days due to the lack
of missile launchers in the Tirolian mecha.
The ship-launched missile magazines sufficed for three large battles or
five or more skirmishes.
- The Reflex furnace could function for about 35 years at normal usage
levels before before an energizer rebuild was necessary.
- At full power, the main propulsion systems can nominally produce up
to 300 Giganewtons of thrust at a minimal reaction mass efficiency
profile, or as little as 12.2 Giganewtons of thrust at a maximum
efficiency setting. At lower power levels, these thrusts are
- At full power, the Seron Thoun class can nominally achieve a maximum
delta-v of 182 kps at the cruising acceleration of 0.1 gees, a maximum
delta-v of 36.4 kps at the battle acceleration of 1.0 gees, and a delta-v
of at most 10.23 kps at the flank acceleration of 2.5 gees. At lower power
levels, these ranges are commensurately smaller.
- The fold systems were not navigationally guaranteed for any single jump
beyond 10 kiloparsecs. If longer voyages were required, the ship had to
conduct multiple fold jumps.
- The maximum sustained atmospheric speed is limited to Mach 3. A higher
speed could be attained while accelerating to orbit, or in emergencies,
but this stressed the engines to above their sustainable heat
tolerances. The maximum hover time on the anti-gravity systems was
limited only by the protoculture supplies and maintenance requirements.
- Makral Ever 200 Reflex cannon (1): This weapon forms
the forward part of the ship. The forward hull opens up vertically, and
a particle beam generation then takes place between the two halves. The
cannon has an effective range of 300,000 km, and the effects against
planets are equal to the heat and blast effects of the detonation of a
fusion weapon of 48 megatons, if fired at full power.
The powerplant can recharge the cannon at a rate of three shots per minute.
However, this will quickly overheat the weapon, and a sustained firing
rate is more in the neighbourhood of three shots per two minutes.
If utilized against starships, the largest vessels can be destroyed by
the leakage of the beam. A direct hit will vaporize the target vessel. The
weapon can also be set to a wider dispersal. While not nearly as effective
as a tight beam against warships, it is capable of clearing a wide area of
fighters and other mecha.
- Makral Deim 653 particle cannon (5): As the Reflex
cannon cannot be fired
fast enough to be effective against multiple heavy opponents, the main
anti-ship weapons are 5 heavy particle cannon. They are mounted behind
movable panels in the hull of the ship. One of these cannons is mounted in
a 'chin' mount behind conformal covers in the lower bow half, one in the
dorsal cannon boom, two in the 'elbow' links to the outriggers, and one is
located on the forward dorsal, in front of the bridge.
The particle beam has an effective range of 300.000 km and a full power
discharge of 1.9 terajoules, equivalent to 380 tons of TNT. Although the
cannon could be fired at lower power settings (and commensurate increases
in the rate of fire) the highest power setting was typical in combat. The
rate of fire at this setting was approximately six salvos per minute.
- Makral Mossil 918 combination cannon (48) : For centuries this combined particle beam and laser weapon has been the standard medium cannon armament on Zentraedi vessels. The laser was originally provided for pulse firings in an atmosphere, to 'drill' a vacuum channel through air through which the particle beam could then travel without significant loss of impact energy to atmospheric scattering. However, the laser was upgraded to be as potent as the particle beam, so that the actual discharge medium could be chosen as the optimum for the local target and environment conditions.
Because of the slow recharge time of the larger weapons, this cannon turret is the most often utilized weapon system on board Zentraedi vessels. For ground support, it is the only effective weapon as the other systems are to heavy to be used around own troops.
As most Zentraedi beam weapon systems, the cannon has an effective range of 300,000 km. Each full-intensity shot has a yield of 1000 MJ, and the cannons can cycle through their firing sequence once every three seconds.
Eight of these weapons are located on or near the tip of the cannon boom,
six others are mounted on each flank of the hull and five are on the
dorsal and ventral hull.
- Deuawhaug Rasar 89 (12): A Reloadable Silo Launch System
(RSLS), or as it is better known, a torpedo tube, capable of firing large
anti-ship and ground bombardment torpedos. The tubes can reload in five to
ten seconds, and have a 40 round magazine close-by. Six launchers are
mounted horizontally in each flank of the upper cannon boom.
The missiles used are the SSA-1 Sniper (Lojredbeth Deuawhaug) and the SSA-2 Scrapper (Letkes Deuawhaug) missiles. The former is a nuclear missile with
a 326 kT reaction warhead, the latter is a conventional tipped missile
with a warhead of 2.3 metric tons.
Both missiles are optimized for anti-ship strikes in deep space, but can
be used in orbital bombardment modes or in an atmosphere.
- Touwhaug Rasar 481 (24): A missile launcher mounted
in a pop-up turret, firing anti-mecha/missile missiles, though the
projectiles can guide on point-blank enemy ships. When the missiles are
released they are already on their intercept vectors, or very close to them.
Each turret has a reload time of 6 seconds and a magazine with a 100 round
capacity. They are mounted for spherical coverage.
The missile system used is the SAA-1 Granite (Gliquoun Touwhaug), a weapon with a conventional blast fragmentation warhead of 278 kg and an atmospheric range of 112 km at a speed of Mach 7.5.
Air group and mecha complement (typical for Border Fleet, 1995):
- The sensor outfit is of very high quality and includes rudimentary hyperspace sensors and highly sensitive EM scanners.
The Seron Thoun class is designed to be the backbone of the Border
Fleets of the Tirolian Mercantile Empire. While the large Sian Dereta class
carried heavier armament and was in general more capable, it also was an
expensive design to produce, and another vessel, cheaper to produce in large
numbers, was required to man the borders. The result was the Seron Thoun.
On first sight, the Seron Thoun resembles a cross between half a Sian Dereta and a Nupetiet Vergnitzs flagship. However, the design has no such
lineage, and is in fact completely original. The resemblance with the Sian Dereta is caused by the use of a nearly identical Reflex cannon, which
accounts for nearly half the length of the ship. The slightly bulging aft
section is dominated by a main thruster of the same segmented multi-reaction
plate design also used in the Nupetiet Vergnitzs (and, for that matter, in
many Invid mecha). Two outrigger bodies and a command citadel reinforce the
likeness of the Sian Dereta. As with the larger ship, these are sensor
mounts and micronian command centers respectively, and the outrigger sensors
(with rudimentary hyperspace scanner arrays and EM sensors) protect the
center body from flanking attacks. Two large disc shaped low frequency radar
transmitters are mounted on the hangar abaft the ventral cannon boom. Three
more large antenna's are mounted in front of the cannon boom.
The Seron Thoun is topped by a micronian command citadel, for like the
Sian Dereta the Seron Thoun has a mixed crew. Underneath the command center
are the barracks for the micronian crew. The Zentraedi forces are located in
the dorsal and ventral bulges of the main cannon boom, and in one large hold
in the center hull. The Zentraedi mecha and the lesser craft are placed in a
hangar bay in the aft ventral of the cannon boom; the Bioroid forces launch
from a hold in the center of the hull, under the Tirolian crew quarters. The
engineering spaces were located forward of the engine and aft of the main
hangar, flanked by the outriggers.
All Border Fleet ships carried a heavy cannon armament at the cost of
torpedo tubes and troop capacity. Apart from the Reflex cannon, the Seron
Thouns carried five large anti-ship particle cannons, more than the Thuverl
Salan heavy cruiser. They were mounted in a chin mount on the ventral of the
cannon boom, in one dorsal cannon boom mount and in an elevating mount in
front of the command citadel, and two in, uniquely, the connecting
structures with the outrigger bodies. Unlike the Sian Dereta, all these
weapons could be brought to bear on the forward arc, where Tirolian tactics placed the
heaviest emphasis. Consequently, the Seron Thoun had about the equivalent
anti-ship firepower of the larger Sian Dereta class. The ships also carried
a complement of particle beam turrets rather large for a ship of their size, and the
standard anti-mecha and anti-missile missile turrets. As
stated, the torpedo armament was minimal, though this did not really matter
with the large cannon armament. The Bioroid and Zentraedi troop
contingents were pared to the bone, although the Border Fleets did receive
qualitatively superior personnel and mecha.
Fifty years after the first Sian Dereta was commissioned, the first dedicated
Border Fleet battlecruisers entered service. The Seron Thoun class
ships were designed to complement the Sian Dereta class, one of which was to
form the nucleus of a Border Fleet battlegroup, typically comprising five
Seron Thoun vessels. As with the Sian Dereta, the Seron Thoun was a
qualitatively excellent vessel with heavy firepower and very powerful and
sensitive sensor arrays. The lack of a large quantity of troops and torpedo
armament made the ships as designed unsuitable for the police and conquest
taskings of the regular Zentraedi, but this was not their designed function.
Many hundreds of these ships were assigned to Tirolian Special Forces groups
rather than to the Border Fleets.
From 1730 through 1969 almost 400,000 Seron Thoun vessels were produced
by the Tirolian Mercantile Empire, and production ceased mostly because the
Border Fleets were at their authorized strengths (for the shrinking empire),
not so much because of any obsolescence of the design. This does not mean
that the Seron Thoun was not getting 'long in the teeth', as the saying
goes, and a design effort for a succesor was already under way. This new
vessel would have been the complement battle group member to the new Sian Macross class, but construction of the Seron Ameg, as the project was named,
never reached the prototype stage. The Seron Ameg was in effect a smaller
edition of the Sian Macross, and the first non-Tirolian Home Fleet vessel to
be equipped with the new Reflex cannon technology, which no longer required
a boom design. As with all Tirolian ships, save the core fleet of the Robotech
Masters, the Seron Thouns lost power to protoculture depletion in the first
decades of this century, stranding the ships in the border regions or making
them easy targets for hostile forces such as the Invid and other inamical
Like its larger siblings, the Seron Thoun is a design well suited
for conversion into a micronian manned capital ship. In place of the
Zentraedi and Bioroid troops, a full division of Terran troops can be
carried, in addition to expanded naval mecha numbers. Five Seron Thoun
lookalikes were contructed by the United Earth Government as the Valivarre class, so that, combined with the SDF-3, the Pioneer fleet would look like
a returning Border Fleet battlegroup. The Tirolian Republican Navy has
procured several ships based on the Valivarre design (Nairok class). However,
there must be thousands of stranded, undamaged Seron Thoun vessels spread in
the old fringe regions of the empire, and reconstituting and converting such
a vessel should be an economically more viable prospect for the poorer races.
No suitable Seron Thoun has been found, so far, and no race has announced any
plans for active salvage operations.
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