Tuesday, July 25, 2017

Skyship Combat Mechanics VII

Previously Posted Sections

1. Introduction
2. Wind Direction & Strength
3. Maneuvering
  3.1. Movement Rates
    3.1.1. Sailing Skyships
    3.1.2. Other Skyships
    3.1.3. Ramming Speed!

    3.1.4. Monsters
    3.1.5. Powering Through

  3.2. Maneuverability
  3.3. Turning
    3.3.1. Basic Turning Capability

    3.3.2. Tight Turns
    3.3.3. Caught In Irons
    3.3.4. Slowing Down
    3.3.5. Emergency Maneuver

  3.4. Climbing & Diving
    3.4.1. Ascending
    3.4.2. Descending
    3.4.3. Effects of Altitude
    3.4.4. Gales & Storms
  3.5. Collisions & Boarding Maneuvers

4. Combat
  4.1. Deck Weaponry
    4.1.1. Weapon Types
    4.1.2. Armor Ratings

The Grand War Galley of Meryath
4.2. Hitting a Target

The mechanics presented here are intended as an extension to existing role-playing games. 

4.2.1. Skyships:  Especially if established RPG heroes operate deck weapons, then use the combat mechanics of the chosen role-playing; use the crew’s attack rolls in order to hit targets.  There are a few methods on how to plug in armor ratings (AR) to an existing RPG.  Method 3 remains independent from RPG mechanics.  Pick what works best.

Method 1:  Convert the target’s AR to the chosen game system, and run combat accordingly.  Combat modifiers (see 4.2.3). can be subtracted directly from the target’s original AR if this is the better way to convert numbers.  For example, an elite artillerist bonus of +20% would reduce a mighty dragon’s AR of 65 to just 45.

Method 2:  Convert the target’s AR and add combat modifiers to the die roll to hit the target.  For example, the elite bonus of +20% could be applied to a d20 hit roll, where +20% equals a +4 bonus to hit.

Method 3:  If neither of the first two approaches are desirable, the third does away with conversion entirely.  Assume a basic score to hit a target of 50%.  Add the target’s AR to this score.  Roll percentile dice and apply the modifiers listed in 4.2.3 to the roll of the dice.  If the result is equal or higher than the hit score, the attack succeeds.  If a target’s hit score exceeds 100%, an unmodified roll of 95+ with the dice still succeeds (considered a critical hit).  An unmodified roll of 5 or less is a critical failure.

Line-of-Sight Limitations:  A deck weapon cannot shoot past intervening masts and sails on the same deck.  This is particularly true to swivel (*) weapons.  For example: a deck-mounted scorpion on a ship’s port side cannot aim at anything off the vessel’s starboard unless the helmsman deliberately tips the vessel on the target’s side (a piloting skill check may be needed for this).  One skyship can hide another if the line of sight crosses through any part of the intervening vessel, unless the one farther back is at least twice as large or at a different altitude level.  Use your best judgement.

Diagram 9. Monsters' Ranged Attacks
4.2.2. Monsters:  With an RPG’s combat system, use the monsters’ attack routines in order to hit a target.  Otherwise, set the monsters’ attack score at 50 minus the monster’s SR.  For example, a small white dragon with an SR of 20 has a basic hit score of 30, while a large red with an SR of 40 would enjoy a hit score of 10.  Proceed as described in 4.2.1. (apply the target AR and any other combat modifiers; see 4.2.3).  If a hit score is in the negatives, an unmodified roll of 5 or less still misses (considered a critical failure).  An unmodified roll of 95 or more is a critical hit.

Bear in mind that some monsters’ ranged attacks may not necessarily be limited to a 60˚ arc-of-fire.  For example, a dragon can turn its head and breathe fire off to one side, aiming at any single target in its three front hexsides.  Likewise a manticore shooting spikes with its tail: its arc-of-fire would be the three rear hexsides.  See Diagram 9 above.

4.2.3. Combat Modifiers:  Without wanting to add too many variables, several combat modifiers stick out as unavoidable, especially if running combat independently from a role-playing game’s established mechanics.

Skyship Crew Experience:
–10%     Crew is unfamiliar with siege weapon operation* (or)
  Nil.       Crew has basic knowledge of siege weapon operation (or)
+10%     Crew has trained with the specific siege weapon’s type (or)
+20%     Crew is veteran or elite class

(*) Operating salvaged starfolk weapons incurs an additional –10% penalty.  Non-starfolk operators have at best basic knowledge of alien technology, unless trained by starfolk such as the Kahuulkin (see CAL1 “In Stranger Skies,” pg. 59).

Commander’s Skill:
–10%     If poor, with a +4 penalty to the vessel’s initiative in Phase A4 (see 4.4. Combat Sequence).
–5%       If mediocre, with a +2 penalty to initiative
+5%       If good, with a –2 bonus to initiative
+10%     If excellent, with a –4 bonus to initiative

If skill is unknown, make a random roll: 2d10—1-3. Poor, 4-7. Mediocre, 8-13. Average, 14-17. Good, 18-20. Excellent.  Also check 4.3.4. Boarding Attacks.

+5%        Short range
–5%        Long range
Shots at extreme range (beyond long range, see 4.1.1) are limited to experienced crews or better.  They require an unmodified critical hit unless some special aiming device is used (dwarven optics, combat prescience, or an item specially enchanted for this purpose).

Diagram 10. Various Bearings in Combat
Relative Velocities:
  • Different Bearings:  Subtract current MV rates of both target and attacker if moving with different bearings.  For example: a skyship with an MV of 5 aiming at a dragon with an MV of 3 incurs a –8% penalty to hit.
  • Parallel Bearings:  Subtract the slower MV from the fastest; the difference is the attack penalty if both have identical bearings.
  • Pursuit/Head-on Bearing:  One follows another with identical bearings, or both head directly toward one another results in no modifier to hit each other.  The same holds true if both attacker and target are motionless (sails furled, hovering, or has not moved during the previous Movement Phase).

Skyship’s a-Jolly-Swayin’
Shooting deck weapons while a skyship is turning (it hasn’t yet moved a hex forward to stabilize) incurs a –10% penalty to hit, or –20% during a tight turn (see 3.3.2. Tight Turns).

Target Size:
+5%       Target is Class C monster or vessel 45’ or larger
+10%     Target is vessel 90’ or larger
+15%     Target is Class D monster or vessel 180’ or larger
Use normal role-playing game mechanics for monsters Class B or smaller, and individual heroes riding them.

Sun Glare
–10%     Target is higher and sun lies within the attacker’s field-of-fire (a 60˚ cone).

Cloud Obstruction
–20%     Clouds partially block line-of-sight
–40%     Inside a storm cloud or at night (see 3.4.4. Gales and Storm Clouds)
Clouds can otherwise completely mask the presence of a monster or a skyship from 4 hexes away or more.  An observation roll may be needed to detect a hidden target.  Clouds are much larger than any battle side portrayed here, so if clouds are present at all, divide the playing surface into two or more large sections to show which areas are affected.  Clouds may also negate sun glare.

Dealing with Altitude:  Most siege weapons on skyships are designed to shoot at targets on the same horizontal plan.  Aiming any deck weapon upward is limited to a 45˚ angle (one level higher per hex of distance).  Aiming a deck weapon with line-of-sight trajectory at a lower altitude is limited to approx. 22 degrees (one level lower for every two hexes of distance).  Deck weapons with parabolic trajectories can always aim at a lower target, provided it flies outside their minimal ranges, their projectiles eventually dropping vertically until they hit or crash into the ground below.  See the notes at the end of Table 8 in 4.1.1. Deck Weaponry, about how altitude affects range.

4.2.4. Fighting in the Great Vault:  There are no parabolic trajectories in the Great Vault.  Anything thrown, catapulted, or otherwise propelled keeps on going until it hits something or is pulled into a nearby world’s orbit.  Damage is never halved at medium and long ranges.  Siege weapons with parabolic trajectories can be set to hurl projectiles in straight line-of-sight trajectories level with their ships’ decks.  Vessels fitted for navigation in the Great Vault are enchanted with artificial gravity, enabling roll maneuvers for the purpose of aiming deck weapons at targets immediately above or under.

Void-enabled skyships possess individual life-preserving envelopes, artificial gravity, and enchanted sails able to trap ethereal and atmospheric winds equally well.  Winged monsters able to travel the Great Vault can use ethereal winds like sailing skyships.  There is no such thing as “burning up in reentry” as skyships rely on different sorts of long range travel which do not involve physical velocity.  Ship combat takes place at more “earthly” speeds.  Use common sense when addressing combat in outer space, although keep in mind that absolute scientific orthodoxy is neither required nor necessarily welcome, as Calidar embodies first and foremost a world of fantasy.

©2017 Bruce A. Heard. All Rights Reserved.

  4.3 Damage
    4.3.1. Structure Rating (SR)
    4.3.2. Damage Location & Effects
    4.3.3. Boarding Attacks
    4.3.4. Area of Effect Attacks
    4.3.5. Fire Damage
    4.3.6. Swarm Attack
    4.3.7. Proportional Damag
    4.3.8. Defense Checks (DC)

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