Combat in space poses some interesting challenges. Ship propulsion is magical in nature; the missile weapons the ships employ are not. Once a missile is fired, momentum keeps it moving at the same speed and in the same direction until it hits something or encounters a gravitational or magnetic pull.

CDN ships are equipped with two primary weapon systems, cannons and ballistae, each of three different types. The cannons, made of cast bronze, are 6 pounders (light); 12 pounders (medium) and 18 pounders (heavy) and are fired from the gun decks. The lighter, more manoeuvrable light, medium and heavy mostly wooden ballistae are mounted on the forecastle and quarterdecks. Within many Spheres the autochthonous Gods suppress the operation of gunpowder. In the vast reaches between the Spheres no such limitations apply…

Cannons and ballistae are both considered to be Bombardment Engines. Except for light ballistae, they are difficult to aim at individuals. Cannons and the larger ballistae can only target buildings, other war machines, vehicles, ships, tight groups of at least ten individuals or single creatures of Huge size.

The ranges given on the table below are divided into short, medium, and long categories. These distances don't reflect how far the projectile will travel, of course, but how accurately the weapon can be aimed. Standard range modifiers of -2 (M) and -5 (L) apply. Beyond maximum range there is every likelihood the shot will simply sail right on past a ship-sized target. Moreover, firing through the gun ports means that for the cannons the direction of fire is fixed. Weatherdeck mounted ballistae have no such limitation; built on pivoting frames that allow for quickly repositioning, they can change their facing with each shot.

These large engines require a trained crew to operate effectively. Reasonably, the larger the engine, the larger the crew needed. If fewer crewmen are available, the weapon rate of fire is reduced proportionately, thus if 1 member of a 4 man team is absent, the ROF is 1/2 that obtainable by a full crew; if 1 member of a 5 man team is absent, the ROF is 2/3 that obtainable by a full crew; if 2 members of a 6 man team are absent, the ROF is 1/3 that obtainable by a full crew, and so forth. If the available crew is less than half the required number, then the weapon cannot be operated at all.

Additionally, the THAC0 given for cannons reflects the competence of a crew where all members are proficient; in that event the chance of misfire is 15%. When half the crew is untrained (non-proficient) the THAC0 worsens by 2, the ROF decreases by half, and the chance of misfire increases to 25%. If the entire crew is untrained THAC0 worsens by 4, the ROF decreases to one third and the chance of misfire increases to 50%. However, if there is an artillerist or bombardment engine specialist supervising a trained crew, THAC0 improves by 1 and the chance of misfire decreases to 10%; if an artillerist or bombardment engine specialist is actually a member of the crew, THAC0 improves by 2 and the chance of misfire decreases to 5%, the best achievable THAC0, with the least possible risk. The consequences of a misfire are determined by rolling 2d6.

The given THAC0 for ballistae also reflects a fully proficient crew. However, moreso than cannon, ballistae are rather high-maintenance devices. When half the crew is untrained (non-proficient) the THAC0 will worsen by 2, the ROF will decrease by half, and there is a 20% chance (an attack roll between of 1-4) that one of the several crucial systems (the sinew and hemp torsion skeins, the windlass, the turntable, etc…) will foul, jam or otherwise fail, rendering the weapon unusable and necessitating the undivided attention of an artillerist for 3d10 rounds to repair. An untrained crew cannot operate a ballista.

Bombardment engines do enormous damage, so much so that cannon fire can harm creatures that are otherwise immune to non-magical or blunt weapons, and ballistae will slay those impervious to lesser missiles. Additionally, armour class derived from physical armour or a shield is completely ignored at short range, is penalized by 5 at medium range, and by 2 at long range. Only the benefits afforded by dexterity, cover and magical bonuses apply against shot and bolt.

Each class of cannon fires three different types of shot: solid, chain and canister; each ballista, two types of bolt: solid and flechette-style arrow fasces. The ballista bolts are tipped either with solid heads or with incendiaries that ignite upon impact.

• Solid shot are cast iron balls weighing, depending on the calibre of the cannon, 6, 12 or 18 lbs.
• Chain shot are two sub-calibre balls, or half-balls, joined together with a chain. The chain wraps around like a bola, and is devastating effective in taking down rigging. They also come in 6, 12 and 18 lb calibres.
• Canister shot, similar to grapeshot, are 6, 12 or 18 lb cans filled with dozens of musket balls. They break open on firing to turn the weapon into a giant shotgun for use against enemy personnel.

• A heavy ballista will launch an impressive spear weighing up to 8 pounds. The steel bolt is 6 feet long with a shaft 2 inches in diameter. The 'feathering' consists of about 8 inches worth of hammered brass laminates. Affixed to this intimidating rod is either a steel point weighing 4 pounds or a fasces of 8 arrows.
• The medium ballista bolt weighs 6 lbs, is 4 feet, 9 inches long, 1.5 inches in diameter and carries either a 3 lb point or a fasces of 6 arrows.
• The light ballista bolt weighs 4 lbs, 12 oz, is 3 feet, 6 inches long and 1 in diameter and carries a 2 lb point and can be effectively aimed at an individual of Small (dwarven) size or larger.

The steps in safely and effectively firing are cannon are:

1. A wet swab is used to mop out the interior of the barrel, extinguishing any embers from a previous firing which might cause the next charge of gunpowder to go off prematurely.
2. A charge of gunpowder (the standard 1-lb to 5-lb cloth cartridges suitable to the cannon and sufficient to propel the shot over the distance of the target) is placed in the barrel, followed by a cloth wad (typically made from canvas and old rope), and rammed home with a rammer.
3. The shot (ball, chain or cannister) is placed in the barrel and rammed in, followed by another wad to hold the shot in place.
4. The cannon is 'run out' by the efforts of the ordnance crew hauling on the tackle until the front of the gun carriage is pressed up against the bulwark and the muzzle extends through the gun port.
5. A quill filled with priming powder (very fine gunpowder) is placed in the touch hole (vent) in the breech (rear) of the cannon, thereby piercing the cartridge bag containing the main charge of gunpowder, and ignited by using a gunlock (flintlock).
6. The most skilled and experienced ordnance mate on the gun crew operates the gunlock by pulling a cord. He stands behind the weapon, safely beyond its range of recoil, and sights along the barrel, taking careful aim and firing when the movement of the ship lines the gun up with the enemy, thereby lessening the chance that the shot will pass above or below its target.
7. When the cannon is fired, the recoil sends it backwards until it is stopped by the breech rope, a sturdy hawser made fast to ring bolts let into the bulwarks, and a turn taken about the gun's cascabel (the knob at the end of the gun barrel).

Ballistae, both solid point and each flechette, can carry an incendiary charge which can set ablaze wooden and canvas constructions (i.e. most of the materials used in shipbuilding). Dry wood, rope and canvas catch fire whenever struck by a fire attack. Flammable materials protected by wet hides or continual soaking catch fire only on a second 1d20 roll of 12 or higher if struck by a the larger charge of a solid point projectile, 16 or higher if struck by a flechette.

In addition to that normally inflicted by the ballista attack, fire adds 1 point of damage per incendiary charge set ablaze during the first round. On the next round, the attacker rolls 1d20 for each fire ignited in the first round; on a roll of 10 or more, one additional point is inflicted. If 1 defender per blaze spends the whole round fighting the fire, and taking no other action, there is more damage only on a roll of 15 or more. If no damage is inflicted, the fire goes out. Additionally, for every point of fire damage a ship suffers, a volume of air sufficient (for measurement purposes) to insufflate 1 ton of ship weight becomes fouled The process is repeated each round until the ship loses all its structural points or the fire goes out.

A ship's HP is equal to her tonnage and is divided equally between hull and rigging.