Expanse

Ship Systems Conversion for The Expanse Ships

Playing Area:

The normal rules where leaving the board edge are can be in effect but the Expanse has long range pursuit as a common tactic. A rolling map would be a better simulation but it depends on the scenario. Attacking a station would use a fixed map for, leaving the area would be disengagement. 

Another idea is to have a strategic map and a tactical map. The tactical map is the playing area while the strategic map could be large scale map with the tactical map being a component laid out on it, using a card template. Ship movement can be scaled down, for example 10mu = 1mu and plotted on the strategic map using markers.

Sequence of Play:

• Add to step 5: Missile movement occurs after ship movement (the missiles chase the target). 

• If the ship moves outside of the missile's movement range (24) then it misses and is removed from the map. 

• Missiles actually attack during step 7, as usual.

Movement:

• Use the Fleet Book Volume 1 vector movement rules

• Fleet Book Volume 1 rolling ships rule is in use

Hulls:

• Belter ships: 6-row hulls. Belter ships use civilian level technology, generally not having access to military grade ship systems.

• Purpose-built Belter warships have 5-row hulls. Merely attaching some salvo missile racks onto a freighter hull does not make the hull stronger/improve ship systems reliability.

• UNN ships: 4-row hulls.

• MCRN ships: 3-row hulls.

Armor: 

• No ships have armor.

• Note that ships in the Expanse are incredibly vulnerable to PDS fire due to not using armor.

Screens: 

• No ships have screens.

Stealth:

• Most MCRN ships have stealth-1.

• Some EarthCorp ships (Anubis class) have stealth-2.

• No UNN ships have stealth (tech is too expensive).

• Note that stealth affects missile lock-on/launch range.

• Stealth also affects K-guns, reducing range bands by 1mu for each level of target stealth as it normally would.

• Stealth has no effect on PDC fire.

ECM:

• Some warships, particularly MCRN ships, mount ECM units.

• ECM affects an enemy missile's die roll to hit.

• ECM does NOT affect the mounting ship's sensors/fire controls, nor does it affect enemy sensor range for detection purposes.

• If using the optional sensors rules, then each level of ECM on the mounting ship reduces enemy identification range by 9mu.

• Note that this refers to identifying a sensor blip as a particular ship class, not the type (escort, cruiser, capital).

Sensors:

• All ships have basic civilian level passive sensors (range 24mu).

• UNN, MCRN, and Belter warships have military grade active sensors (range 54mu).

• Note that most Belter ships are NOT warships, unless designated so by the scenario instructions (military grade active sensors can be purchased on the black market, but are too expensive for most civilian Belter ship owners).

FTL: 

• No ships have FTL.

Drives: 

All ships have standard drives.

• MCRN ships tend to have thrust-5 or higher.

• UNN ships tend to be thrust-4 or lower.

• Belter ships vary from thrust-2 for a freighter to thrust-4 for a warship.

Weapons:

The only weapons in use in the Expanse are K-guns (Railguns), missiles, and point defense systems (PDC).

Railgun:

• K-guns, some ships use keel-mounted (1 arc, forward only, or 2-arc) and turrets are also in common use.

• Use standard range K-guns.

PDC:

• PDS act like MKP packs at close range 6mu or less, no ammo limits. They cannot be used for point defence in any turn used in this role.

Missiles:

Expanse missiles are guided munitions unless intercepted by a PDC they have a very high probability of hitting the target

• Ships mount either salvo missile launchers or external racks.

• Available missile types are standard missiles (1d6 damage) or heavy missiles (3d6 damage).

• There are no extended range or multi-stage missiles.

• Missiles may be fired singly, up to 6 from a salvo launcher each turn.

• Each may be fired at a different target if desired.

• The SSD icons show circles for individual missiles; they do not represent salvos.

• External racks may fire as many missiles/turn as desired.

• Missiles have longer range, being capable of coasting until close to the target, where they activate their drives for terminal guidance.

• Double the normal missile ranges (from 24mu to 48mu).

• Ships may lock-on to and launch at enemy targets up to 54mu away, modified by the target's stealth level.

• Stealth-1 reduces missile lock-on/launch range by 9mu, and stealth-2 reduces missile lock-on/launch range by 18mu.

• However, missiles move their normal movement rate.

• Put a marker on the map for each missile in step 3 as usual, and move it up to 24mu during step 5, after all ships move.

• If it does not hit its target this turn, next turn, it may move up to an additional 24mu chasing its target.

• If a large body such as an asteroid, moon, or planet is between the missile(s) and the target, the missile(s) hit it instead.

Combined example:

A UNN ship wants to engage an MCRN cruiser that is 48mu away.

Normally it could engage a target with its missiles up to 54mu away, but the enemy cruiser has stealth-1, which reduces lock-on range by 9mu.

The new lock-on range is 45mu (54mu – 9mu = 45mu), however, the MCRN cruiser is 48mu distant, and so cannot be fired on.

The next turn, both ships close to 36mu distance between them, and the UNN ship now fires missiles at the MCRN cruiser.

Put the missile markers on the map 24mu away from the UNN ship, pointed at the MCRN cruiser. The next turn, the missiles may chase the target, moving up to another 24mu. If the target is not within 24mu, they miss.

• Missiles are fired at a designated target, using an available fire control on the launching ship.

• One fire control is adequate to target as many targets as desired for missile fire.

• Exception: One fire control is required for EACH heavy missile fired.

• MCRN vessels carrying heavy missiles use Advanced fire controls, and each unit may control TWO heavy missiles.

• Missiles that are moved onto the target ship and are within lock-on range of the launching ship automatically hit unless shot down by point defense, or diverted by ECM.

• If the target mounts ECM, roll a d6, adding the ECM level to the die roll.

• On a modified roll of "7+" the missile misses.

• It may then target a random enemy ship within 3mu, scoring a hit on a 1-4 (again, modified by the target ECM level) unless shot down.

• Each missile may only attempt to hit a random enemy ship once, and if it misses, is removed from the map.

• If for some reason, the launching ship loses all of its fire control systems, moves out of lock-on/launch range (54mu, modified by target stealth level), or is destroyed, the missiles may still engage the designated target ship, but must roll a D6 per missile.

• Add the targets ECM level to the die roll.

• On a modified roll of "6+", the missile misses.

• It may then target a random enemy ship within 3mu, scoring a hit on a 1-4 (again, modified by the target ECM level) unless shot down.

• Each missile may only attempt to hit a random enemy ship once, and if it misses, is removed from the map.

Example:

3 missiles are fired at an enemy cruiser that mounts an ECM unit.

The launching ship leaves fire control range (54mu), trying to escape.

The missiles may still engage the cruiser, and 1 of them is destroyed by point defense.

2 missiles attack the cruiser, rolling a "1" (modified to a "2") and a "5" (modified to a "6").

One missile hits the cruiser, inflicting 1d6 damage, and the other missile misses.

If there are other enemy ships within 3mu, randomly pick one, and the missile will engage it, scoring a hit on a die roll of 1-4 unless shot down by point defense (again, add the targets ECM level to the die roll).

Point Defense:

• 1 PDS icon for each 2 PDS in the TV version.

• Each PDS may engage ships out to a range of 12mu.

• If the target is up to 6mu away, a PDS scores a damage point on a roll of "5" or "6".

• If the target range is over 6mu but not over 12mu, each PDS scores a damage point on a die roll of "6".

Breaching Pods:

• Each carries 1 Marine unit.

• May only be used within 6" of the target ship to be boarded.

• They are vulnerable to point defense fire as they approach the target ship.

• They launch at the end of phase 5 (Ship movement) and automatically attach to the target vessel at the start of step 12 (Boarding Actions).

• They may be fired upon during step 9 (Point defense), with each PDS hit destroying one breaching pod.

• Note that if the target vessel is under missile attack, the target ship must allocate all point defense fire between incoming missiles and Breaching pods BEFORE rolling any dice.

To add to a ship, count each Breaching pod as a Boarding Torpedo, except that no launcher is needed, and each carries 1 Marine unit.

Each Breaching pod requires 1 mass, and costs 3 points.