On Delta Station

Rules Overview

On Delta Station is a ruleset intended to narratively replicate the naval battles of WWII and later in a science fiction context. As such it operates under several fundamental concepts:

Aircraft (or battlecraft as a more general term) are capable of flight ranges significantly exceeding that of any conventional weapon.
Long range detection is unreliable, requiring physical scouting with vehicles.
Scouting is an integral part of all battles and rules (in a simple form) for it will exist.
Weapons fire and scouting becomes more effective as range decreases.
Battles do not continue indefinately; air wings will be depleted of munitions (or aircraft!) quickly and warships will eventually find themselves in a fog of particle shells and waste energy or simply wander into clouds of space weather.
Aircraft and cruise missiles are "alpha damage" units as compared to conventional warships which are "damage over time" units.
Battles fought over large distances will have significant downtimes. This allows for both repairs and the opportunity for a retreat.

Battle Flow

Step 1: Reduce range band by 1 (first turn: start at value for environment)
Step 2: Roll Scouting vs target formation's Fleet Signature. Each faction gets to roll.
Step 3: Scout Intercept. A successful scout intercept gives significant bonuses to all further scouting attempts but the target is not discovered.
Step 4: If no faction has discovered the enemy, go to Step 1. If an enemy is detected, go to Step 5.
Step 5: Launch Strike; strikes may only be launched one per turn.
Step 6: Gunnery; Ships may Gunnery once per pulse. Phase count depends on range.

Pulses: Each turn is divided up into one or more pulses. As a rule the closer the battle is the more pulses happen. This represents ships firing more accurately at closer targets, shorter flight time, etc.
Counterpulses: These are pulses that happen when there is no active battling, giving ships (and other pulse units) time to conduct damage control, regenerate shields, etc. Counterpulses happen after each pulse and the number of Counterpulses after each pulse is determined by distance; longer ranged battles have more 'downtime'. If there is no pulse unit action (such a pure carrier strike) the number of Counterpulses equals the band value.

Air Warfare
	Sword and Starship	Heavy Metal	Infospace
Loadout	Single-Role	Single-Role	Multi-Role
Maneuver Focus	Agility	Speed	Balanced
Range	Short	Long	Medium
Aircraft Size	Small	Small	Large
Features	Firepower	Toughness	Weapon Range
Carrier Size	Fleet Ships	Small	Large

Air attacks happen on a turn basis as it takes significant time to actually conduct even the simplest air evolution. The same does not apply to gunnery attacks from warships which are stable gunnery platforms with ample supplies of ammunition and power. However as ranges increase even long-range weapons spend more time aligning or waiting for a fire control solution than they do actually firing.

Consequently, warships engage not on the turn level but on the pulse level; each pulse is one round of fire. Counterpulses are periods where the defender has time to conduct hurried damage control and regenerate shielding. Range band 3 is typically considered 'long' range for gunnery, with range bands 4 and 5 mostly limited to harassing fire as contacts fade in and out of the targeting scope. Conversely, ships at range band 0 are already firing as fast as they can; instead at these ranges even relatively weak weapons can penetrate layered defenses. Generally speaking no conventional direct-fire weapon can strike out to range band 6 or greater.

Gunnery table
Range Band	Pulses	Counterpulses
Band 0	10	0
Band 1	10	0
Band 2	5	0
Band 3	3	3x1
Band 4	2	2x2
Band 5	1	1x8
Band 6+	0	10

Haze
'Haze' is the general term for the various byproducts of battle such as chaff clouds, expended decoys, scattered blavatsky particle density, electronic interference, smoke from damaged ships, excessive waste heat, space weather and crew exhaustion to name just some. Haze can be considered a battle timer; for a number of turns it will have no effect on battles but thereafter it will steadily increase in effect. The primary effects of haze is command and to-hit difficulties will increase; fighting 'in the haze' is a recipe for chaos.

Concept

Fleet units are organized into several stations representing various elements operating together. The different stations are listed below; the two most important are CORE and ESCORT, together these two make up almost every conventional fleet. Note that station in this usage does not imply that all ships are in one specific location, merely a signifier of the broad position and task they are performing.

Core units are inevitably the most important units in the formation. Archetypically they are capital ships, but merchants or 'leaders' (ie light cruisers leading destroyers) are also equally valid. Core units are also the units that set the speed of a formation; it is for this reason that escorts are generally fast because they must match (or normally exceed) the speed of the core. A fleet travels at the speed of its slowest ship. As a general rule the core is fairly tight and can provide mutual support; as such the stats of the core units are collected together.
Escorts are, as the name implies, the escorting units. They tend to be smaller and more numerous and their main role is to screen and protect the core against enemies. This does not mean that escorts are strictly defensive; they also perform vital roles such as heavy scouting and fixing and, if fitted with torpedoes and the like, are exactly the sort of things that hostile escorts exist to keep far away from the core. Most units explicitly designated as escorts actually represent several individual ships operating together for simplicity. While their naturally dispersed nature means they are less effective at massing firepower at any specific target, this dispersal also means that they can intercept hostiles before they reach the core.
Picket are where ships are deployed in a very loose outer shell to provide scouting of the enemy. This is sometimes done by umbraships which have the advantage of being extremely difficult to detect, but commonly this is taken on by the ubiquitous fleet destroyer or by small, fast light or scout cruisers. There are pros and cons of this, trading out the speed (and expendibility!) of battlecraft for the superior sensors and persistance of warships. This station is (by design) too distant from the core to be directly supported by anything other than battlecraft, hence the importance of speed or stealth; it is about the only realistic defense ships on this station have against a full enemy fleet.
Heavy Escorts are a special case were powerful units from cruisers (commonly) right up to fast battlecruisers (not so common) are pushed forward/outwards from the core. This is most commonly done with the intent of engaging and defeating hostile escorts, though the classic 'SAM trap' would also apply. The downside is that this can be a high-risk tactic; a 4,000 ton destroyer may not be worth throwing a carrier strike or torpedo spread at but a 40,000 ton battlecruiser is another thing entirely. And of course if your scouting is wrong you run the risk of having heavy hitters be totally out of place and play no part in battle.
Wolfpacks is the station for escorts assigned to the offensive role; their mission is essentially to 'sail towards the sounds of the guns' and engage the enemy. Most escorts are capable of performing in the wolfpack role as well and the difference is generally tactical deployment as opposed to material design differences. The actual use of this station can vary quite widely and it is more commonly found among the Sword and Starship milieu or those taking advantage of loopholes in the VNT regarding small ships. Others, such as the Enduscarans, derivisely call it a 'death ride'. Like Distant Scouts, the Wolfpack station exists outside of effective range of core support. Wolfpacks operate much tighter than Escorts, meaning they concentrate damage more effectively. Of course a wolfpack that has to contend with hostile escorts and the enemy core needs every advantage it can get . . .

Saturation

While two ships are better than one, it is typical that in a fleet action having twice as many ships is not equivalent to having twice the combat capability. Ships can often be masked by others, suffer fraticidal weapon effects, have overkill and underkill, fire control errors, etc. Effectively, as fleet sizes go up, the effectiveness of each ship goes down. The term for this is Saturation.
As a general rule, Core and Escort will saturate seperately.
Note that not all situations suffer saturation equally; a dozen destroyers escorting a single battleship is not going to materially impede its capacity to shell another battleship, but that same flotilla of destroyers will certainly suffer saturation penalties when defending against an air attack.

Core Unit Concepts

Ships are divided into two functional groups:

Core ships are single ships, most notably capital ships but also including heavy cruisers and small aircraft carriers.
Escort ships exist as multiples; nominally 4 frigates/destroyers or 2 small cruisers; in narrative terms this is flexible and they do not need to be deployed in exact multiples of 4s and 2s respectively. It is assumed that any oddities are explained by them moving in and out of organization groups or temporary additions/removals. Don't sweat it.

Carrier Operations

Deck actions happen on the operational scale (1 hour) - Some baselines:

CVLs get 1
CVFs get 2
CVHs get 3

Skill check to get +1 deck action

Deck action cost:

Launch (0)
Catapult launch (1)
Refresh CAP and utility (1)
Spot 1 squadron (2)
Recover 2 squadrons (1)
Breaking spot (1+)

Actions can be continued into the next operational turn.

Respotting: Skill check upon breaking a spot; failure means you fuck up and have to restart from scratch. Breaking a spot can involve changing the planes involved or what they're loaded with (what mission they will perform)

Spots can be held indefinitely on the operational scale, though a ship exiting the battlezone will break spot to perform maintenance, return munitions and other dangerous materials to more protected parts, etc etc.

A spot also clogs the flight deck with planes. Carriers are designed by default with a certain degree of flexibility (eg angled decks) but after a certain point the deck is just full of planes.

Small carriers: Any spot will block flight ops
Fleet carriers: 1 squadron spot before flight ops blocked
Heavy carriers: 2 squadron spot before flight ops blocked

Design flaw axial deck; any spot blocks flight ops (WWII style straight deck)

Carriers typically have a maximum number of squadrons that may be spotted before their deck is full. This will vary by ship, but twice the number to block flight ops can be taken as typical.

Multi-carrier ops:

Multi-deck skill level is the cap as to how many different carriers you can have working together effectively. Expect heavy penalties and timing errors (strikes arrive in different pulses) if exceeded.

Units

All Battlecraft are Squadron units, which means they are made up of a large number of individual units. As a squadron takes damage down its damage track, it suffers penalties as it has less operational units. This is called the dropout thresholds. Note that in most cases these penalties are a combination of decreased to-hit and lower maximum hit count, but even one lone striker can still manage to put a torpedo into the keel of a ship and cripple it. It just becomes increasingly more difficult to do so.
Battlecraft that have suffered dropout are not automatically lost. They have a survival chance after battle representing planes forces to ditch ordnance and return home with damage. Some weapons may make this more or less likely; DEMP guns and heavy SAMs for example.

M and H are size classes while P is a parasite craft, units marked as Slow take twice as many deck actions on a carrier

Recon (1 DP) - The proverbial ‘eye in the sky’, air scouts are small fixed-wing aircraft that are essentially flying sensor packages and observation points. Unarmed (or, at best, having a machinegun or two), their primary role is tactical observation, though with appropriate upgrades they can perform light strike in unopposed airspace. They are long ranged but not particularly fast.
Fighterscout (1 DP) - Essentially an element of standard dogfighters modified for catapult as opposed to deck operation; fighterscouts are generally launched not from carriers but from battle-line units.
Dogfighter (3 DP) - An archetypal fighter squadron; (Cosmo)Spitfires, TIE fighters and similar. Dogfighters have high performance and a gun package to send the enemy down in flames. If equipped properly they can make decent light multirole strikers, a la X-Wing.
Striker (3 DP) - Dedicated strike aircraft such as the Ju-87 Stuka or the Y-Wing, Strikers are meant to attack ground and naval targets as opposed to other aircraft. To this end most have the ability to carry one large piece of ordnance (ie a torpedo or rocket bomb) or multiple smaller ones, depending on the mission at hand. While commonly armed for self-defense, all but the most upgraded strikers are not terribly good at air-to-air.
Fighter-Bomber (M, 6 DP) - The fighter-bomber is very much an overgrown dogfighter, larger engines allowing for larger ordnance stowage and heavier defenses. While ultimately only mediocre at the fighter job, they are some of the toughest aircraft flying and rely more on endurance than agility to defeat the enemy. Some even have ludicrous gun packages like superfiring turrets.
Multirole Fighter (M, 10 DP) - Multirole fighters are substantially larger and more capable than their smaller cousins, armed with a powerful missile payload and easily swinging between the superiority and strike role. This combination of performance and firepower comes at a premium though, and while they are much better at missile combat they are comparable to a lighter dogfighter in a knife fight.
Utility (M, 4 DP) - A small unit of all-purpose aircraft, with variations for AWACS, tanker, etc often using a common airframe.
Bomber (M, 10 DP, Slow) - Typically operated from fixed bases that can readily support their increased size, bombers are used both for recon and for attack.
Heavy Bomber (H, 20 DP, Slow) - Heavy bombers are the archetypical ‘bomber’; large, multiengine, laden with ordnance, probably bristling with defensive machineguns. They are fairly rugged as aircraft go thanks to their bulk and, unless fitted with appropriate upgrades, are best at attacking large and slow-moving targets like cities as opposed to point targets.
Penetrator (H, 20 DP, Slow) - To heavy bombers what heavy fighters are to dogfighters, penetrators are loaded with an arsenal of hard-hitting guided and unguided ordnance. In addition to this, they have some combination of speed, electronic defenses and stealth to help them carry out offensive missions. However, fast bombers do not normally have defensive weapons unless upgraded as such.
Warbird (P) - These are not aircraft but small attack ships, though in most ways they act more like aircraft than things typically considered 'ships'. Carried between systems attached to larger ships they are fueled, prepped and launched to do sweeping attacks with their onboard ordnance and cannons before returning to their mothership to resupply.

Traits

Imperial Aggrandisement - gain 1 prestige and 1 legitimacy every time you construct a Supership. Lose 2 each every time a Supership is sunk. Superships count double for Show The Flag bonuses.

Misc Thoughts

Attacks will be done via difference dice classes, representing gun calibers/power. Provisionally they are as follows:

Flak/Small (autocannons, destroyer caliber guns, etc). Default range 1
Medium (mid-sized weapons, cruiser guns). Default range 2
Large (capital weapons, battleship guns). Default range 3
XL (special superweapon type things).

Ships will have different defenses for different weapon classes. For example destroyers might be fairly vulnerable to small-caliber weapons giving them low Flak defense but slow-firing capital cannons would be relatively ineffectual giving them high defense. A heavily-armored battleship would be the inverse.

Using light ships to scout

MPAs

Cruise missile attacks (limited use! no reloads!)

Heritage Ships

Heritage Ships are old hulls, often ones that predate the VNT entirely. Typically unique or nearly so, Heritage ships also tend to be more capable or powerful than the serially-produced and treaty-limited capital ships built under the VNT. However, as every heritage ship had a career that lasted four or more decades, once their stats are completed a GM will roll on the following table to determine what happened to them and what their current status is.

Capital ships may be rolled individually or by class, at player request.

Large cruisers or equivalents will only be rolled by class.

Smaller cruisers and escorts are never Heritage Ships.

01-03 - Cursed - This ship has an uncanny and unfortunate history of suffering harm and as such it is all but guaranteed to suffer some manner of (repairable) damage even doing mundane activities. All the repairs from shell impacts and running over fishing boats have perversely kept it in fit condition though.
04-06 - Infamous - Prestige penalty. No matter how many times to repaint them, the Black Ships of Nebka Ctar will be remembered for what they did.
07-08 - Haunted - Morale penalty. If you hear someone banging on the inside of the reactor containment vessel, don't open it. Ever.
09-13 - Worn Out - The ship is just old, general penalty. She shoulda been scrapped ten years ago but there's no budget for a replacement.
14-17 - Tired Engines - Speed penalty. Even hyperalloy thrust casings only last so long before their efficiency drops by a measurable amount.
18-19 - Rusty Guns - Firepower penalty, If we fire any faster we'll blow out the primary grid along with half the keel.
20-21 - Flawed Protection - Armor penalty. The flaws in the protection scheme went undiscovered for decades and there's no feasible fix.
22-24 - Spite - Save vs sinking but always takes damage. Damn the torpedoes, I have not yet begun to fight!
25-30 - Bulged - speed penalty, armor increase. Thicc.
31-33 - Experimental Shielding - Firepower penalty, shield improvement. The hyper-aegis never caught on because it redirected too much power from the main gunnery grid.
34-35 - BBAA conversion - Firepower penalty, AA improvement. Fuck planes. Seriously.
36-37 - Cosmoblaster EX - Firepower and tracking penalty, add megacannon. All hands, prepare for shock and flash.
38-40 - Speed is Armor - armor penalty, speed increase. It never helped anyway.
41-42 - HAL 9000 - Morale penalty, general improvements. [color=red]Friend computer will ensure maximum mission completion at all times.[/color]
43-44 - Freebooter - Firepower penalty, cargo added. Replacing one of the turrets with a cargo hold still leaves you with two more!
45-46 - Royal Yacht - Upkeep penalty, prestige increase. He liked watching gunnery drills from the Admiral's bridge.
47-51 - Refloated and Reconstructed - speed penalty, AA and firepower (fire control) improvement. Even in death I serve.
52-53 - Electronics Testbed - Shield penalty, sensor and EW improvement. A big fat battleship with tons of room is a great place to test new electronics.
54-55 - Missile Silos - AA penalty, +1 cruise missile carrying. Reach out and touch someone.
56-60 - Refitted Cosmoturbines - speed increase. Replacing obsolete drive coils with new ones gives an old ship a new lease on life.
61-63 - Fast Battleship Reconstruction - +1 speed and armor to any ship with -1 armor. Reroll if not. An extensive and expensive project, but well worth it.
64-66 - Comprehensive Reconstruction - general improvements. Ageless warrior.
67-69 - MORE GUNS - Firepower improvement. Modern spin-seperated tibanna gas gives us 20% greater unit bang per unit buck.
70-71 - Machine Spirit - Your ship is haunted, but probably in a good way. What is the nature of the military emergency?
72-76 - Recently Refitted - Like new! The 3rd turbine room still smells of used socks though.
77-78 - Unsinkable - Save vs sinking. Belli dura despicio.
79-83 - Battle of Insert Location - Prestige increase. Insert Location was a glorious day for the astrofleet of Insert Nation.
84-86 - Demi-Carrier - Firepower and shield penalty, +2 carrying. All the carriers got blown up so we got creative.
87-89 - Rebuilt as Carrier - Becomes equivalent carrier hull with same perks and flaws. May be treated as 'Demi-Carrier' if rolled as class, may be rerolled on a Frankenstein result. It was either rebuild her as a carrier or scrap her under the VNT. We chose the former.
90 - Famous Astroguardian - Large Prestige increase, hero shields. Single ship only. The skalds shall sings songs of your actions.
91 - Mysterious Origin - Gains 3 perks, randomly rolled by GM. Single ship only. When the Visitor crashed out of an astral fold two hundred and twenty-three years ago, we all knew the world had changed.
92-94 - Frankenstein - Roll twice and add them together. Convert any duplicated flaws to upkeep penalty, reroll any contradictory results. The number of flaws may not exceed the number of bonuses, upgrade any 'bad' result to an equivalent 'tradeoff' result until net zero is achieved. It's an ugly piece of work but it gets the job done.
95-97 - Very Frankenstein - Roll thrice and add them together. Convert any duplicated flaws to upkeep penalty, reroll any contradictory results. The number of flaws may not exceed the number of bonuses, upgrade any 'bad' result to an equivalent 'tradeoff' result until net zero is achieved. We cut the ship down the middle and welded a hundred-meter section taken from its sunken sistership in. Seems to work.
98-00 - Frankenstein's Monster - Roll five (5) times and add them together. Convert any duplicated flaws to upkeep penalty, reroll any contradictory results. The number of flaws may not exceed the number of bonuses, upgrade any 'bad' result to an equivalent 'tradeoff' result until net zero is achieved. Dear Lord, why?