Navis Imperialis - Torpedoes: Torpedoes are massive self-propelled ship-to-ship missiles. While expensive to maintain, these weapons possess considerable destructive potential, and many captains use an enemy's tendency to avoid torpedoes to dominate a battle, forcing enemies to move in particular directions.The most common forms of torpedo are over 60 metres long (on Destroyers), 200 metres long (on Cruisers) and 300 metres long (on Battleships) and contain both a powerful warhead and a short-lived plasma reactor similar to, but less stable than those used by starships and Titans. Each torpedo is built to accelerate quickly from its launching tube into the void, hurtling in a straight line towards the enemy.While many torpedoes are fired to deter enemy movement and thus may never strike, each individual weapon can do significant damage to a voidship, and thus are feared by many captains. Guided by a crude and murderous Machine Spirit (artificial intelligence) and the calculations of a ship's Master of Ordnance, a torpedo uses basic Augury sensors to scan for the heat from plasma drives, a target silhouette, any electronic output, and even an enemy ship's mass to locate enemy vessels.Once the Machine Spirit acquires its target, powerful manoeuvring thrusters adjust the torpedo's course to intercept. Unlike weapons batteries and Lances, torpedoes cannot be deflected by a ship's Void Shields -- most shields intercept incoming fire based on its speed. Torpedoes travel slowly enough (relatively speaking) that shields will not intercept them and they can pass through these powerful gravitic energy barriers unimpeded.Upon impact, the forward momentum drives the torpedo's body deep into the vessel's structure before the warhead and plasma reactor both detonate, inflicting damage far greater than that of a single Lance strike or macrocannon shell.The torpedo types employed by the Imperial Navy include:Plasma Warheads - These explosives are the standard armament for Imperial torpedoes. They are designed to blast through a starship's armoured hull, using their high speed to punch deep into the target vessel. The plasma reactor that powers a torpedo's drive forces it deep into the bowels of the ship and then overloads, contributing to the fury of the warhead's detonation. This reduces complexity, making their manufacture simple. Thus, these torpedoes are the staple of Imperial Navy warships.Melta Warheads - These weapons are even more feared by starship captains than standard torpedoes. Mercifully rare and extremely brutal, Melta Warheads detonate a precisely-organised series of Melta charges upon impact with a target, burning through hull plating and consuming sections of the vessel's interior in a roiling conflagration.Virus Warheads - In cases when a vessel must be captured intact, but the target's crew are considered expendable, Virus Warheads are seen as an ideal solution. Pirates more interested in inert cargo, salvage, and the possibility of expanding their fleet lust after these rare and unstable armaments.Vortex Warheads - Only a few remaining Forge Worlds still maintain the technological craftsmanship to manufacture these rare weapons. The Vortex Warhead is not a crude explosive charge, but an arcane device that tears open a rent in the very fabric of reality, consigning vast chunks of its target to the Warp. The swirling energy within this tear in the fabric of reality immediately draws all matter in its blast radius through it, leaving gaping wounds in the target vessel. When attacked by these torpedoes, word of these horrifying weapons spreads like wildfire through target crews.Boarding Torpedoes - More manned spacecraft than torpedo, these torpedoes fulfill a comparable role to that of assault boats. However, boarding torpedoes are less manoeuvrable and less armoured than assault boats. To offset these flaws, they are also much smaller targets. The crews of a boarding torpedo are able to make minor adjustments to the torpedo's flight path.