Sunday, June 12, 2011

Skyships of Adventurer: preview !

Having been away from home for an extended period, I have had time to just about finish Sorcery and superscience (book 2 of adventurer).  Here's the fluff intro to the skyship construction chapter, and some actual mechanics for building the hulls.  This is, obviously incomplete.

 Skycraft and Seacraft: Fluff and background technobabble.

One aspect of Swords and Sorcery that needs consideration is that of the influence of the past and of ancient and lost civilizations. A key element in the mood of such tales is living in a world that was once home to vastly more powerful and or advanced civilizations, now fallen. Typically, little new is created in the younger civilizations once this is realized; creativity turns to scavenging the powers of the ancients, and seeking out their knowledge to learn in rote manner; seldom is there found the knowledge to create or improve such artefacts, or the wisdom to understand mysterious knowledge. This is typically expressed as ancient, often prehuman sorcery, or ancient superscience….or both, now indistinguishable.

Magical and superscience artefacts are typically ancient, irreproducible, and only partially understood. They have effects, which are vastly powerful, but often unrelated to their actual purpose. An example in fiction is that of a deadly weapon, which is in fact a self-powered electrical radio ; primitives discover it can be used to kill one another by hurling it into a victim’s bath, and that is its new function.

In one direction, then, is sorcery, generally non-human, often completely beyond comprehension if not apish use; in another is the science and artefacts of a lost but often human civilization of which the present users are degenerate remnants. All of this is simply a wordy way to introduce flying devices to the world. Simply put, they are optional, but easily added.

In Adventurer, the basics of starship construction is used to develop two specific kinds of technological remnants: seacraft and skycraft. In worlds where this technology exists, or remains, the common ships of low tech cannot compete, and are absent or badly retarded and primitive. Campaigns lacking this technology will require the typical historically based ships, and will be discussed later. Skycraft and Seacraft.

All such vessels consist of up to four basic ancient components: a hull, a levitator, a motivator and a radium furnace. The radium furnace powers the levitator and motivator, and they in turn act upon the hull to produce the desired effects. They are all imperviously sealed components, which are mounted onto the hull and interconnected by contemporary, if advanced methods ; for instance, the radium furnace may transmit its energizing rays via a series of mirrored steel tubes connecting certain key points on the furnace to those of the motivator; but uses braided wire of purest gold to connect to a levitator. Similarly , the motivator may transmit its effects to the hull via a pool of salted oil in which it sits whereas the levitator may simply change vibrational frequency of the hull via inert organic substances.

In short, while the components are effectively indestructible, their connections are all contemporary, and thus all too vulnerable to disruption. In game terms, the exact details can be ignored save that they can be damaged, and are difficult to replace; actual description of the connectors is entirely for game flavour.

A radium furnace and a motivator and or Levitator are connected to each other and mounted in the hullframe, and then common currently available materials (such as wood or steel) are added to create decking, bulkheads and hull planking to allow the components to function as a ship. It is quite possible (and often common) for a ship to be reduced by combat or fire to its basic indestructible elements and still fly, (although it will not float) if they are still connected. A hull disconnected from a levitator will plummet and crash, often deforming the frame; loss of connection to a motivator will simply cause a sky or seacraft to coast to a stop. Loss of connection to the radium furnace will cause both effects.

The final component of any design is the radium gas used to fuel the furnace; this is held in large tanks of contemporary material and construction.

Note that the motivational effects generated by the hull are damped by contact with and proximity to the ground; a large amount of either water or air is required to insulate the motivators effect from the geostatic field of the planet generated, as is well known, by the radiant orgomantic inertia of a large body. Obviously, this will not affect the horizontal field effects of a levitator.

The effects of the geostatic field are most pronounced when the ship is within  approximately 20 meters per 100 rTons displacement of solid dry land. Thus, a 100 dTon ship would experience geostatic shut-off of its motivator beginning at approximately 20 meters altitude.

A ship that has its movement field damped by proximity has its Motivation rating reduced to zero over perhaps ten minutes regardless of its original rating.. Similarly, power builds slowly over the same time when setting out. Note that operating in proximity to the geostationary field also requires much higher level of input from a radium furnace, and thus landing and launching can be major operating expenses; a levitator is also effected by this, although its potential . Ships without extenuating reasons will typically manoeuvre above a landing area, and descend directly, using the motivator only for small corrections. Similarly, launching is typically accomplished by a direct assent to the minimum altitude for that hull, at which time the motivator is powered up.

(yes, this is simply a fiddle to explain why they all ride horses and lizards or whatnot across the trackless deserts when skycraft are unavailable);

The hull is an open frame, a spidery web of Orichalum, an indestructible metal of mysterious properties. A given hull will contain a given volume and no more, and mass is effectively irrelevant. The hull produces lift when activated by a levitator, and velocity when acted upon by a motivator. These frames can be deformed (with significant effort), and this can reduce volume, but cannot be stretched, expanded, cut, spliced or otherwise damaged. Without the action of a motivator or levitator it is simply an inert web of malleable but impervious metal wires, about as dense as aluminium.
The largest known hull still in existence has a displacement of 5000 tons of phlogisten bearing radium gas.(rTons)
Hulls are available only in discreet sizes due to standardization by the ancients. Current hulls exist in 100rTon  incrementsup to 1000 rTons, and then three larger sizes  which are almost always used for military craft.

The motivator requires a connection to a radium furnace to work and a connection to a hull. When so connected, the hull is able to move, with or without inertial effects depending on the needs and design of the campaign. Basic speed is in hexes per day (about 150km/hex) , up to the rating of the motivator, modified by the levitator, if present. Note that the motivator is immobile without a hull, even with a radium furnace connection. Ships lacking a levitator are limited to functioning in water. Land vehicle construction is generally impractical (or impossible) due to geostatic issues discussed above.

The levitator functionally allows the ship to float, and enhances the effect of the motivator. It requires a functioning connection to the hull, and to a radium furnace. The maximum altitude of a skycraft is its levitator rating, and its speed is the product of its motivator rating and levitator rating when above the geostatic limit of the ship. Each altitude band is approximately 2000 meters.

Note that the largest ships with minimum rated levitators will have a very restricted operating range for using the motivator – a 5000 dTon ship has a Geostatic floor of approximately 1000 meters, and a levitational ceiling of 2000 meters (and with motivator rating of 1, an average speed of about 6-7 km/hour –look out zeppelins and sailboats!)

Note that for altitudes bands greater than ½ the UWP size rating of a world, atmospheric effects come into play.  See skyship  operations  for details.

Radium Furnace
The radium furnace is the heart of any ship. Burning Phlogistonated radium gas, it powers motivators and levitators; other wondrous ancient engines also rely upon Radium furnaces, from massive water pumps to tiny home lanterns. Note that a radium furnaces output is directly related to its size, although it is not necessarily a linear relationship. Also note that they do not provide electricity (a primitive, unreliable and terribly inelegant means of powering devices) but rather energizing rays of the fourth quantum (or higher). A radium furnace must have a rating at last equal to the highest rated component on board ship (in many, but not all cases, this will be the motivator or levitator)

Radium Gas.
Gaseous radium is, in fact, a matrix storing the phlogiston required by the Radium furnace. The Radium gas is efficiently recycled and returned to the ships tanks in a dephlogistonized state by the Radium furnace. Dephlogistonized Radium is then recharged with elemental Phlogiston and is again able to support the Furnace. Rephlogistonizing is generally carried out before the full tank is depleted, to avoid the steep fuel requirements of restarting a furnace (as above). Phlogiston is generally provided by refineries at most ports; unrefined phlogiston can be obtained at the smaller ports, and produced by the ship from any organic matter is equipped with a phlogiston mill. Use of unrefined phlogiston is essentially free, but carries penalties for reliability and maintenance.

In general operation, above the geostatic floor, the Radium furnace will burn (dephlogistonize) radium gas to produce radiant energization for the Motivator and Levitator. The motivator requires Phlogistonated Radium gas equal to 1% of the hulls displacement * the rating of the furnace per two weeks of operation. Note that restarting a furnace requires a far greater amount of Gas than simply running it, equal to two weeks operation so it is usually left running, and thus the motivator is always available. Gas consumption is always based on the rating of the furnace, not upon the actual setting of the Motivator, due to the well known semipartial effects of the radium antidecay factors.

A levitator will require gas equal 10% of the hull volume to lift a ship one altitude band for two weeks continuously. Consumption is proportional to use, and so is based on the average altitude across time. A levitator with a rating of four an thus keep a ship at level 4 for two weeks (burning 40% of its displacement in fuel), or at level 1 for eight weeks (burning 10% of its displacement in gas per week.
Note that both refineries and mills are ancient devices, and require connection to a furnace to work.

Skyship construction

The general procedure for construction of skyships (and seaships) is essentially that of traveller; for convenience, the specific version is the of the Mongoose Traveller SRD for both the core rules and High guard.

The design sequence for building a skyship is as noted in the two documents unless changed below; the actual components used are limited to those those noted below as usable.  Obviously, any new components are applicable only to this supplement.

Note that some changes in nomenclature of ship design have been made, mostly for flavour or personal prejudice of the author.  In particular, Traveller components and ships are measured in displacement tons (dTons) , based on the displacement of liquefied Hydrogen; this is converted to rTons in skyships, which is based on the displacement of phlogiston bearing radium gas, a completely fictional substance. Hardpoints are referred to as mounting or mount points, and standard traveller turrets are referred to as gun mounts ; barbettes are barbettes, and Bays are now small or large turrets. The terms are intended to conform to nautical design terms of the ironclad/predreadnaught era, and to satisfy the Authors personal whims.

1. The Hull

A Skycraft may have several configurations – standard (a basic ship-like or hydrodynamic structure, able to land on, and at need navigate in water), streamlined (a wing, disc or other lifting body specialized for flight, capable of landing on water or land, but incapable of effectively navigating in the former) or exotic (which includes fanciful hull shapes, such as monsters, castles or human heads).  Further, Hulls may be open, closed or sealed. 

·      Open hulls are the default, and have at least one working deck exposed to the elements and the slipstream;.  Open hulls are often seacraft that have been refitted with levitators to allow flight, and may even be simple sailing craft with a hull frame, Furnace, motivator and levitator added.

·      Streamlining a ship increases the cost of the hull by 10%. Streamlining may not be retrofitted; but must be included at the time of construction. 

·      Closed hulls have  all working areas protected and enclosed, and are typically more teardrop or cylinder shaped if a standard hull Closed status reduces hull capacity by 10%and increases the cost of the hull by 10% (but improves the effects of armouring, see below). A hull may be retrofitted to closed status

·      Sealed hulls are often spheres or actual fantasy rocket shapes, are both protected and sealed against atmosphere and water, and able to maintain internal environment and structure against extremes or pressure from both directions. Sealed hulls may not be retrofitted, and increase cost by 20% and reduce capacity by 20%.

·      Exotic hulls may be open or closed, and have the cost of the hull reduced by 20%, calculated before open or closed structure is considered.


Armor is added in 5% increments of the ship’s tonnage.

Armor Type
1 per 5%
5% of base hull (Max 3)
2 per 5%
20% of base hull  (max 6)
4 per 5%
50% of base hull (max 12)
8 per 5%
100% of base hull (max 24)

Av = availability
LC = Less common
U =unusual
R= rare

For example, a heavily armoured warship might take Steel armour twice. This would take up 10% of the hull’s volume and cost 100% of the base cost of the hull, but give 12 points of armour.It would require a major city or dedicated warship yard to construct due to its unusual type (Steel)

AntiThermium (U): Antithermium coating on the hull increases the ship’s armour against heat, flame lance and inferno weapons by 3. Adding Reflec costs 0.1 Megacredits per ton of hull and can only be added once.

Semi-organic (U): A semi-organic hull automatically repairs minor breaches such as smallarms fire, and prevents decompression in sealed hulls. It costs 0.01 Megacredits per ton of hull.

Contravisibility (R): This coating partially absorbs light, causing it to be invisible at night, and functionally invisible at greater than long range in daylight, blending into the haze. This gives a –4 DM on any rolls to detect the ship. Adding Stealth costs 0.1 Megacredits per ton of hull, and can only be added once.

Hull and Structure
Initial damage is applied to the Hull; once the Hull is breached, further damage goes to the Structure. When all Structure Points have been lost, the ship has been smashed to pieces. A ship has one Hull Point and one Structure Point per 50 tons of displacement.



Hull parameters may be modified by original purpose, reinforcement and quality.


As discussed previously, all hulls are artifacts, and many of them are repurposed; thus, the current use of a hull may differ significantly from its original design intent, simply due to lack of suitable hulls when needed.

Merchantile hulls are the moist common, and the default. They are not well configured for heavy weaponry and as a result, barbettes cost 50% more, and take up 2 mount points and double internal volume.  Turrets may not be mounted.

Paramilitary hulls include private security forces, police, and support for ground units (often mercenary) Half of the mounts points must be light or standard gun mounts or unused; Barbettes may be installed as normal, and small turrets cost 50% more and take up two mount points, although internal volume is unaffected.  Large turrets are not allowed.
Paramilitary hulls cost 20% more than standard.

Military hulls may mount any weapons or combination of weapons,; however, a total of 10 tons * total mountpoints must be dedicated to weapons use or left empty.  Note that this minimum is for all mountpoints, and could be satisfied by a single turret (for example) in a 1000 ton hull.
Military hulls cost 50% more than standard.

Civil Hulls are those originally used for purely social support purposes, such as rescue, civil maintainance and medical transport or intervention.  As they are highly specialized, cost and volume requirements for all non-gunmount weapons are doubled.

An exploration hull is primarily intended for hazardous work; it may mount any weapon at standard cost, but the hull cost is doubled.

 Hulls may have additional structure and hull points by allocating extra volume.

Reinforced Hull

Hull Size
Reinforced Structure per 5%
Reinforced Hull per 10%
100 -300

Of the four major components of a skyship (hull, Motivator,Levitator,Furnace) the hull is most likely to var in quality due to age; partly this is because the hull is also the only component that does not suffer from catastrophic failure past a certain level of damage and neglect.  Hulls degrade slowly, and with great effort can be upgraded, although its capacity never changes. 

Hull per

The Hull Per row determines how many Hull and Structure points a skycraft will have at that quality level. Normally, a ship has one Hull point and one Structure point per 50 tons. At higher technology levels, a ship can have more Hull and Structure for its tonnage.

Note that the relationship between cost and hull per rows is not linear or symmetric. This is intentional, and  includes consideration of availability.


Seacraft are typically boarded across the top deck, or via a gangplank; skycraft also have this capacity, but generally also have  at least one boarding hatch per 100 tons, typically at the keel deck.The average keel hatch is similarly designed to a nautical gunport, and is basically watertight when closed;and  is large enough for three people in armor to pass through at the same time. Under normal circumstances, boarding hatches are locked down from the inside and require a Very Difficult (–4) stealth  check to open.
Ships with cargo space may have horizontal cargo hatches in the main deck, allowing up to 10% of their cargo to be transferred at any time; vertical hatches (at any level, though presumably at keel level) may be installed instead on skyships.

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