Designing a ship in Sol Cruiser is fun and easy. Simply pick a propulsion system, determine type and number of weapons, sensors, small craft, troop berths, etc., then design a hull around it and calculate performance. All components must be carried inside the ship's/fighter's hull. No external carriage of ordnance or fighter craft is allowed.
In case of fighters, since each fighter flight represents 4 actual ships, design a propulsion system, hull, sensors for each fighter individually, but when assigning weapons, divide their mass and volume by 4. A battery of beam weapons is considered to have 4 actual weapons, with 1 weapon per fighter. Calculate performance for each individual fighter. Also, add 1 to sensor rating of sensors mounted on fighters (this is already reflected in the ship stats below). Hit points for fighters are calculated by calculating hit points for a single fighter, then multiplying them by 4. Size and signature are also calculated per individual fighter, but are not multiplied.
Uncrewed vehicles (drones, etc.) are designed as regular ships, except that their components (with the exception of hull and fuel) have their mass and volume multiplied by .9. Fuel consumption, however, is calculated using unmodified engine mass. Note that detonation laser warheads, if desired, must be carried as submunitions, otherwise a det warhead attack by an uncrewed vehicle results in its own destruction.
Missile flights also represent 4 actual missiles, but their design is treated as if the whole flight was a single unit. Just pick a warhead, add an engine and fuel, then calculate performance. This has been factored into component masses, therefore you need to buy only 1 warhead and 1 engine per missile. However, if you want to put sensors on your missiles you have to multiply their mass by 4. Missiles do not benefit from subsystem mass/volume multipliers for unmanned craft (the only exception being missile-mounted beam batteries, which do benefit from the .9 multiplier) and for non-FTL engines. Missiles may not be armored.
All ships' power plant and crew accommodation masses and volumes are factored into other components.
There are 3 tech sub-levels in 2300AD, referred to as New Military (NM), Old Military (OM) and Old Civilian (OC) techs. Before beginning to design a ship, determine to which sub-level it belongs, and pick components from that sub-level.
Hulls and Armor:
Hull mass (in tons) is determined by hull volume (in cubic meters), armor level, and the ship's tech level.
Hull Volume 0-50: 3, 51-100: 5.5, 101-150: 8, 151-200: 10, 201-250: 12, 251-300: 13,5, 301-400: 15, 401-500: 18.5, 501-750: 23.5, 751-1000: 29, 1001-1500: 37.5, 1501-2000: 45.5, 2001-2500: 53, 2501-3000: 60, 3001-3500: 67, 3501-4000: 74, 4001-4500: 81, 4501-5000: 87, 5001-5500: 93, 5501-6000: 99, 6001-6500: 105, 6501-7000: 111, 7001-7500: 117, 7501-8000: 123, 8001-8500: 129, 8501-9000: 135, 9001-9500: 141, 9501-10,000: 147, 10,000-11,000: 154, 11,001-12,000: 162, 12,001-13,000: 170, 13,001-14,000: 180, 14,001-15,000:190, 15,001-16,000: 200, 16,001-17,000: 210, 17,001-18,000: 220, 18,001-19,000: 230, 19,001-20,000: 240, 20,001-25,000: 260, 25,001-30,000: 290, 30,001-35,000: 330, 35,001-40,000: 360, 40,001-45,000: 390, 45,001-50,000: 420, 50,001-60,000: 470, 60,001-70,000: 520, 70,001-80,000: 580, 80,001-90,000: 640, 90,000-100,000: 700, 100,001-125,000: 860, 125,001-150,000: 930, 150,001-200,000: 1020
Hull masses listed above are for an NM, Unarmored hull. For an OM hull, multiply the mass by 1.5, for an OC hull by 2.25. Hulls with Light armor multiply their mass by 2, Medium armor by 4, Heavy armor by 8, Vheavy by 16.
Streamlined hulls have their mass multiplied by 1.25.
Sol Cruiser ships rely on Thermo-Nuclear Pulse (TNP) engines, sometimes known as the Daedalus Drive.
At NM tech level, each ton of TNP drive generates 1.5 tons of thrust, and consumes .0005 tons of fuel per ton of engine (not thrust!) per hour. At OM level, the figures are 1.0 and .00075 respectively, and at OC they are .67 and .001. Engines and fuel have volume in cubic meters equal to mass in tons. Engine mass also includes the FTL drive. Spacecraft not designed for interstellar travel (fighters, missiles) multiply their engine mass by .9. Non-FTL capable ships are denoted by an "N" after their thrust rating.
Beam weapon batteries: At NM level, a Light Battery weighs 20 tons, Medium–40 tons, Heavy–80 tons, and Very Heavy–160 tons. At OM, multiply all weights by 1.5, and at OC, by 2.25. Beam weapon batteries have a volume in cubic meters equal to mass in tons.
Detonation warheads are rated for damage (1 to 4 dice of damage) and penetration (Lt. to V. Hvy). At NM, a 1 die, Lt. warhead weighs 8 tons. Med warhead weighs 1.5 as much as a light one, a Hvy one 2.25 times as much, and a V. Hvy 3.375 times as much. A 2-die warhead weighs 1.5 times as much as a 1-die, a 3 die 2.25 times, and a 4 die 3.375 times as much. For OM, multiply by 1.5, for OC by 2.25.
For example, a 2 die NM Medium warhead would weigh 8 (base weight) x 1.5 (for 2 die) x 1.5 (for medium)=18 tons.
Detonation warheads may be mounted on missiles or be used as submunitions. In the latter case, double the warhead's weight. Detonation warheads have volume in cubic meters equal to mass in tons.
The following figures are for NM. For OM and OC multiply by 1.5 and 2.25, respectively.
1 hex range: 10 tons, 2: 15, 3: 22.5, 4: 34, 5: 50, 6: 75, 7: 110, 8: 165, 9: 250, 10: 375, 11: 560, 12: 840, 13: 1260, 14: 1900, 15: 2850, 16: 4270, 17: 6400, 18: 9600, 19: 14400, 20: 21600, 21: 32400, etc. For each additional level of performance, multiply sensor mass by 1.5.
Hangars and Troop Berths:
Housing for a company (approx. 120 troops with vehicles and interface craft) occupies 2500 cubic meters and masses 2500 tons. The mass includes the troops, their equipment, etc. A squad (10 troops) occupies 250 cu. m. and tons, a platoon 800 cu.m. and tons.
Missile tubes have no extra mass/volume. Missile bays and drone bays have the same mass/volume as the missiles which they carry, but may be used to recover launched missiles or drones and refuel them in the course of the battle. Ships with missile tubes may recover their missiles but may not refuel them. Each missile bay or tube holds one missile flight. Drone bays may also be used to launch missiles (each missile occupying twice its regular volume), but missile bays may not carry drones.
Hangars for manned craft (such as fighters) have a volume three times greater than the volume of carried craft, and mass in tons equal to volume in cubic meters. This includes mass of the fighter itself. Hangar bays may be used to carry missiles and drones, but they are treated as if they were manned craft in terms of their mass/volume requirements (i.e., they are considered to have volume three times greater than actual).
Hangar bays and troop housing may be designed to be interchangeable in function by multiplying their mass and volume by 1.25. For example, an interchangeable bay with usable volume/mass of 2500 would have a total mass/volume of 3125.
Stealth: At NM level, each level of stealth occupies 5% of hull volume, at OM 7.5%, at OC 10%. No spacecraft can have more than two stealth levels. Each cubic meter of stealth measures masses 1 ton.
RATING THE DESIGN
Hit Points: To determine hit points, divide the mass of an NM, Unarmored hull equal in volume to the ship you've just designed and divide it by 4 if the ship is NM, 5 if OM, 6 if OC.
Size: Size is dependent on volume. 0-10 cubic meters: -3 (most submunitions fit in that category), 11-100: -2 (most missiles), 101-1000: -1 (most fighters, corvettes, small frigates), 1001-10,000: 0 (frigates, destroyers, light cruisers), 10,001-100,000: +1 (heavy cruisers, capital ships), 100,001-1,000,000: +2 (very large capital ships), 1,000,001-10,000,000:+3 (the Death Star?)
Signature: Signature is a function of mass, engine thrust, tech level and stealth features. The heavier the ship, and the more powerful propulsion system it packs, the greater the chance of it being detected.
Mass: 0-100 tons: .25, 101-1000: .5, 1001-10,000: .75, 10,001-100,000: 1.0, 100,001-1,000,000: 1.25, 1,000,001+: 1.5
Thrust: Same as for Mass, except use Thrust in tons.
Tech level: newer technologies have introduced materials with inherent signature-masking properties. OM ships subtract .25 from their signature, NM ones subtract .5.
Stealth: Subtract .25 per level of stealth built into the ship.
Thrust: To find ship's game thrust rating, divide its thrust in tons by its mass in tons. Multiply the result by five. Round all fractions down. The resulting value is the ship's thrust rating.
Fuel Points: Fuel points determine the ship's endurance in terms of maintaining its thrust. Calculate how many hours the ship's fuel last by dividing fuel mass by engine mass and multiplying the result by fuel consumption value for that tech level. Divide the number by 18. This will give you the number of 18-hour turns during which the ship can sustain its full thrust. Multiply this figure by thrust rating to obtain the number of thrust points, one thrust point being defined as sufficient thrust to change ship's course by one hex.
If using Replenishment rules, calculate how many tons of fuel each thrust point represents by dividing fuel mass in tons by number of thrust points.
DESIGNING CONVENTIONS FOR 2300AD SHIPS
Even though it is a completely new set of rules, Sol Cruiser has been designed to be able to reproduce the capabilities of 2300AD ships designed with Star Cruiser's Naval Architect's Manual. Certain conventions have been followed, although some ships depart from them considerably.. For example, x1 weapons are treated as Light batteries/detonation warheads, x2 as medium, etc. Each 5 to-hit dice rolled for a detonation warhead represents 1 die of damage in Sol Cruiser. Therefore, a Star Cruiser 10x2 det laser warhead becomes a Sol Cruiser 2 die medium warhead. As far as thrust is concerned, Star Cruiser ships with movement allowance of 1-2 receive a thrust rating of 1, 3-4 of 2, 5-6 of 3, 7-8 of 4, 9-10 of 5, etc. Armor value of 1-3 becomes Light armor, 4-6 Medium, 7-8 Heavy, 9-10 Vheavy.
SHIP DESIGN EXAMPLE
Let's shoot for 8000 cu m hull NM.
Hull: an 8000 cu.m. Unarmored NM hull masses 123 tons. This will give a total ship mass of 8123 tons. Since hulls are about the only construction elements to have only mass and virtually all other elements have the same mass 1 ton per cubic meter, for purposes of maximizing the design it makes sense to set the ship's total mass at hull volume + hull mass, which gives 8123 tons.
Engine: the Kennedys are some of the fastest ships in the 2300AD universe, with Star Cruiser rating of 9 or even 10 under some circumstances. This translates into a Sol Cruiser thrust rating of 5, which in turns means a max acceleration of 1 G. This means 8123 tons of thrust, which translates into 5415 tons of NM engine. We'll add fuel later, once we know how much room is left.
Stealth: since the Kennedys are also known for their stealth, let's go with two levels, or 800 tons/cubic meters.
Weapons: in Sol Cruiser, the 10 x1 lasers and 20 SIM-14 missiles translate into 3 light batteries and 5 missiles. The batteries have total mass/volume of 60 tons, while the missiles are designed from scratch using the rules above and have the following stats:
Warhead: 2 die, Medium, 18 tons. Let's shoot for a 45 ton missile with a
thrust of 4, which gives 24 tons of engine, 3 tons remaining for
Endurance: .216 tons of fuel/ 18 hour turn yields 13 turns of endurance at full thrust and 52 thrust points. Mass of 5 msls in: 225 tons. They are carried in missile tubes, so no extra mass or volume.
Other craft: a 250 cu.m. sensor drone, with total bay mass/volume of 500.
Sensors: let's give it a 10 (375 tons).
Total so far: 7123 tons. Use the rest (1000 tons) for fuel. 5415 tons of NM engine means 2.7 tons of fuel per hour or 48.6 tons per 18-hour turn at maximum thrust. 1000 tons of fuel yields 20 turns at full thrust, or 100 thrust points.
Hit Points: dividing 123 by 4 yields 30.75=31 hit points.
Thrust 5, 20 turn endurance at max thrust, 100 thrust points, 10 tons of fuel/thrust point
Size modifier 0.
Signature .75 (mass) +.75(thrust) -.5 (NM) -.5 (for stealth) = .5
Kennedy Ship Status Display (an example)=====