Naval Combat Reference

Hybrid Naval System — Combat Reference

This system resolves ship combat quickly toward one of four outcomes:

1. one ship escapes;
2. one ship surrenders or disengages;
3. one ship founders;
4. the ships grapple and play returns to ordinary 5e boarding combat.

Exact facing, squares, and turn-by-turn sailing distances are not tracked. Ships use three range bands, a short Integrity track, one roll per battery, and a limited number of crew Orders.

Companion Documents

• Naval Economic Reference
• Naval Armory

Table of Contents

• Core Ship Statistics
• Range Bands
• Checks and Crew Quality
• Starting Combat
• Round Sequence
• Helm Maneuvers
• Orders and Support Actions
• Weapon Attacks and Salvo
• Damage, Integrity, and Sinking
• Critical Hits
• Ramming
• Grappling and Boarding
• Undercrewed Ships
• Spells and Character Actions
• NPC Break Conditions
• One-Page Flow of Combat

Core Ship Statistics

Integrity

Integrity is the ship’s short combat endurance track. Ordinary ship attacks reduce Integrity rather than hundreds of Hull HP.

Hull HP remains relevant after combat for repair costs. Each stat block lists a Hull Segment value that converts Integrity loss into Hull HP damage.

Armor Integrity

Magical shields and similar effects may grant Armor Integrity. Lose Armor Integrity before normal Integrity. Armor Integrity does not trigger sinking thresholds and normally recovers according to its upgrade.

If one hit inflicts more Integrity damage than the remaining Armor Integrity, apply the excess to normal Integrity.

Damage Threshold

If a battery’s total Salvo is below the target’s Damage Threshold, the Hull takes no Integrity damage.

Orders

Orders are the number of crew-intensive ship actions available each round. The Helm maneuver does not cost an Order.

Typical Orders include:

• fire one battery;
• Aim one battery;
• clear one Reload box;
• Brace;
• Damage Control;
• Emergency Repair;
• Prepare Grapples;
• raise or lower Deck Nets;
• activate Bilge Pumps or another crew-intensive upgrade.

A character’s independent action—casting a spell, firing a personal weapon, moving on deck, or treating one creature—does not cost an Order unless it directs a crew task.

Orders are a ship-level action budget, not a replacement for player turns. During each naval round, every player character may take one normal action, one bonus action, movement, and reactions at the phase where they make sense. The group also allocates the ship’s Orders, representing commands carried out by officers and crew. Routine NPC specialists are abstracted; do not roll separate initiatives for them.

Maneuverability and Handling

Class	Handling
A	+4
B	+3
C	+2
D	+1
E	+0
F	−1

A critical effect or damaged rigging can worsen Maneuverability.

Range Bands

Every hostile ship is at one of three ranges relative to the player ship.

Extreme

The vessel has just become visible or is nearly gone.

• Only weapons with Extreme range can attack.
• Battery attacks have disadvantage.
• A successful Flee maneuver escapes the encounter.

Long

Most artillery can engage.

• Weapons with Long or Extreme range can attack.
• Battery attacks have disadvantage.
• One successful Close or Flee maneuver changes the range by one band.

Short

The ships are close enough for direct fire, spells, ramming, grappling, and boarding.

• Short-range battery attacks are normal unless another effect changes them.
• Ranged attack spells and character-scale attacks can affect the other ship.
• Ram and Grapple maneuvers are available.

This system is intended for one player ship against one or two important enemy ships. Resolve allied fleets and distant background ships narratively.

Checks and Crew Quality

Player Helm Check

d20 + one relevant ability modifier + proficiency bonus if proficient with vehicles (water) + Handling

Dexterity is common for responsive steering, Intelligence for planned positioning, Wisdom for reading wind and waves, and Strength for forcing an oared vessel through a maneuver.

NPC Helm Check

d20 + Crew Quality + Handling

Speed Edge

During an opposed range-changing check, compare Speed.

For every full 10 feet by which one ship is faster, it gains +1, maximum +3.

A war galley ignores wind penalties but still uses its listed Speed.

Player Battery Attack

d20 + Dexterity or Intelligence modifier + proficiency bonus

Appropriate proficiency may be firearms, the relevant siege weapon, or vehicles (water), at the GM’s discretion.

NPC Battery Attack

d20 + Crew Quality

Crew Quality Check

When an action is performed by the crew as a whole:

d20 + Crew Quality

Typical crew DCs are 12 for routine danger, 15 for difficult combat work, and 18 for desperate work.

Starting Combat

1. Identify all participating ships.
2. Set the initial range: Extreme, Long, or Short.
3. Record each ship’s Integrity, Armor Integrity, ready batteries, Reload boxes, Orders, Crew Quality, and active critical effects.
4. Each helmsperson rolls initiative using the Helm Check formula.
5. The highest result chooses whether to declare their Helm maneuver first or second. Keep this declaration order for the encounter unless command changes.

Do not reroll initiative every round.

Round Sequence

Each naval round follows five phases.

1. Helm Phase

Helmspersons declare and resolve maneuvers in the established declaration order.

2. Orders Phase

Captains, bosuns, gunners, and support crew allocate Orders. Resolve Aim, Reload, Brace, Damage Control, repairs, boarding preparation, and crew-dependent upgrades.

3. Attack Phase

Resolve all battery and character attacks. Attacks from opposing ships are simultaneous: record damage now, but do not remove a ship’s unfired attacks because it was hit earlier in this phase.

4. Consequences Phase

Apply:

• Armor Integrity and Integrity loss;
• critical effects;
• fires;
• sinking saves;
• morale or Break Conditions;
• reload markers and temporary effects.

5. End Phase

Check whether a ship:

• escaped;
• surrendered or broke off;
• reached 0 Integrity;
• grappled and transitioned to boarding.

Then begin the next naval round.

Helm Maneuvers

A maneuver that is not opposed normally requires a DC 12 Helm Check. When ships attempt incompatible range changes, make an opposed check instead.

A ship that wins an opposed maneuver by 5 or more may change range by two bands, where possible.

Close

Move one band closer: Extreme → Long or Long → Short.

If the target attempts Flee or Parting Shot, resolve an opposed Helm Check.

Flee

Move one band farther: Short → Long or Long → Extreme. At Extreme, success escapes.

If the enemy attempts Close, Grapple, Ram, or another range-contesting maneuver, resolve an opposed check.

Evade

On a successful DC 12 Helm Check, attacks against the ship have disadvantage until its next Helm Phase. Range does not change.

Hold Steady

On a successful DC 12 Helm Check, the ship’s battery attacks have advantage this round. Enemy battery attacks against it also have advantage.

Parting Shot

Attempt Flee. On a success, the ship’s batteries also have advantage this round. Enemy attacks against it have advantage until the next Helm Phase.

At Long or Extreme range, this advantage usually cancels the normal range disadvantage.

Ram

Available only at Short range. Resolve an opposed Helm Check. On a success, use the Ramming rules.

Grapple

Available only at Short range. Resolve an opposed Helm Check. On a success, the ships are Grappled.

A Prepare Grapples Order or a connected harpoon adds its listed bonus.

Hold Range

Use when one ship attempts to maintain its current band against an enemy Close or Flee. Resolve an opposed Helm Check. On a win, range does not change.

Orders and Support Actions

Fire Battery — 1 Order

Fire one ready battery at one target during the Attack Phase.

A battery with any Reload boxes cannot fire.

Aim Battery — 1 Order

The battery has advantage on its next attack this round. Aim also negates the Culverin’s Artillery penalty.

Aim cannot stack with itself.

Reload — 1 Order per Box

Clear one Reload box from one battery.

A battery gains Reload boxes equal to its Reload rating after it fires. An Efficient battery with twice its listed crew reduces the boxes gained by 1, minimum 0.

Brace — 1 Order

Until the next Orders Phase:

• reduce Ram damage suffered by half;
• crew have advantage on saves against being knocked prone, displaced, or thrown overboard.

Damage Control — 1 Order

Choose one:

• make a DC 15 Crew Quality or tool check to clear one Damaged critical effect;
• prevent a Fire from escalating this round;
• grant advantage on the next sinking save before the next Orders Phase.

A Disabled component cannot be restored during combat unless a specific magical effect says otherwise.

Emergency Repair — 1 Order; Once per Ship per Battle

Consume one Supply store and make a DC 15 Intelligence check with carpenter’s tools or a DC 15 CQ check.

On a success, restore 1 Integrity as Patched Integrity. It disappears after the encounter and still creates a normal repair liability.

Prepare Grapples — 1 Order

Gain +2 on a Grapple maneuver this round. This may represent hooks, chains, boarding poles, prepared marines, or a gangplank.

Bilge Pumps — 1 Order

Requires the upgrade. Gain advantage on sinking saves until the next Orders Phase.

Rally — Captain Action, No Order

Once per battle, the captain makes a DC 13 Charisma check.

On a success, choose one:

• restore 1 lost CQ caused by combat;
• give one Helm Check, battery attack, or CQ check a d6 bonus;
• immediately test an NPC Break Condition with advantage.

Assess — Officer Action, No Order

Make a DC 15 Intelligence (Investigation) check. On a success, grant advantage on the next attack or opposed Helm Check against the assessed ship.

Weapon Attacks and Salvo

Batteries

A battery is every identical weapon assigned to fire at the same target.

• Make one attack roll for the battery.
• Multiply the weapon’s Salvo by the number of weapons.
• Apply ammunition and upgrade modifiers per weapon.
• Compare the total Salvo with the target’s DT and damage table.

Splitting identical guns between targets creates separate batteries and separate attack rolls.

Range

• Short: normal attack
• Long: disadvantage
• Extreme: disadvantage and only Extreme-capable weapons may fire

Advantage and disadvantage cancel normally.

Integrity Damage

On a hit:

Total Battery Salvo	Integrity Damage
Below target DT	0
DT through 49	1
50–99	2
100 or more	3

A natural 20:

• increases Integrity damage by 1, maximum 3;
• causes a critical hit;
• doubles normal damage dice only when damage dice are being rolled against creatures, components, or fortifications.

Called Shots

At Short range, a battery may target a component instead of the Hull.

Target	AC	Effect on Hit
Rigging or propulsion	12	Inflict Rigging Damaged; no Integrity damage
Weapon battery	15	Inflict Weapon Damaged; no Integrity damage
Helm	18	Inflict Helm Shock; no Integrity damage
Exposed crew or officer	Creature AC	Resolve creature or casualty damage; no Integrity damage

Called shots have disadvantage unless ammunition or an effect removes it.

Personal Weapons and Spells

At Short range, characters may attack normally.

For an effect directed at the Hull:

1. use actual damage as Salvo;
2. compare it with DT and the Integrity table;
3. one spell or character attack cannot inflict more than 1 Integrity unless it deals at least 50 damage;
4. ship immunities and resistances apply.

Ships are normally immune to poison and psychic damage and to conditions that require a living creature.

Damage, Integrity, and Sinking

Taking Water

At 2 Integrity, the vessel is Taking Water.

At the end of a round in which it lost Integrity or has an unresolved Fire or Hull Breach, make:

DC 15 Constitution save

On a failure, lose 1 additional Integrity.

Critical Flooding

At 1 Integrity, the save becomes:

DC 18 Constitution save

On a failure, reduce Integrity to 0.

Use the ship’s Constitution modifier. Bilge Pumps or Damage Control may grant advantage.

Foundering at 0 Integrity

At 0 Integrity:

• Speed becomes 0;
• the ship cannot take Helm maneuvers;
• it cannot make Emergency Repairs;
• all crew-dependent checks have disadvantage;
• it sinks or breaks apart in 1d4 + 2 rounds.

The scene immediately becomes an evacuation, surrender, salvage, rescue, or boarding scene. Continue naval attacks only when the fiction clearly requires them.

During each foundering round, the GM may call for movement checks, falling debris saves, flooding hazards, or attempts to save cargo and trapped crew.

Postcombat Damage

After combat, each lost Integrity point creates Hull HP damage equal to the ship’s Hull Segment. Record critical component damage separately.

Critical Hits

Roll 1d10 when a battery scores a critical hit.

d10	Critical	Effect
1	Ammunition Scattered	Choose one loaded or reloading battery. It cannot Reload or Fire until one Order is spent collecting and reorganizing ammunition.
2	Fire	Mark Fire. If not controlled during Orders, lose 1 Integrity in Consequences. If it survives two Consequences phases, it escalates and inflicts 2 Integrity each round.
3	Hull Breach	Handling −1 and disadvantage on sinking saves until repaired. A second unresolved Hull Breach is Disabled and cannot be repaired in combat.
4	Knocked Off Course	Maneuverability becomes E until the end of the next Helm Phase.
5	Morale Shaken	CQ −1 until the captain succeeds on Rally or the ship scores a critical hit against an enemy.
6	Rigging Damaged	Speed −10 ft. and no Speed Edge bonus. A second unresolved result disables the rigging: Speed is halved and Helm Checks have disadvantage.
7	Rigging Tangled	Maneuverability worsens by two classes. A second unresolved result disables the rigging as above.
8	Ship Shaken	Crew and exposed characters make DC 15 Dexterity saves or fall prone. The ship loses 1 Order next round.
9	Helm Shock	Helmsperson makes DC 12 Constitution save or loses the next Helm action. A second unresolved result damages the helm: Handling −2.
10	Weapon Damaged	A randomly determined active battery cannot Fire. A second unresolved hit to that battery disables it until port repair.

Repairing Criticals

Damage Control can clear one Damaged result with a successful DC 15 check.

A second unresolved hit to the same system normally makes it Disabled. Disabled systems require postcombat repair.

Magical repair may override this when its spell or item explicitly repairs a vehicle, structure, or ship component.

Ramming

On a successful Ram maneuver:

1. The target suffers the attacker’s listed Ram Salvo.
2. The ramming ship suffers half its own Ram Salvo.
3. Resolve both through the normal DT and Integrity table.
4. A ship that used Brace halves the Integrity damage it suffers, rounding down, minimum 0.
5. A Naval Ram adds +30 to outgoing Ram Salvo and absorbs the ramming ship’s first self-damage result by becoming Disabled.

A successful ram may also leave the ships at Short range. It does not automatically Grapple unless a specialized grappling ram or narrative effect says so.

Grappling and Boarding

Grappling

A successful Grapple maneuver joins the ships.

While Grappled:

• neither ship can change range;
• neither can Flee, Close, Ram, or Evade;
• batteries may still fire if their fiction and range permit;
• characters may cross using ropes, hooks, swings, gangplanks, flight, teleportation, or ordinary movement.

A grappled ship may escape by:

• cutting or removing all lines during standard combat;
• winning an opposed Helm Check after the lines are cleared;
• destroying the grappling component;
• forcing surrender or taking the enemy helm.

Transition to Standard 5e

Once the ships are Grappled, end the naval round and roll ordinary 5e initiative.

Use deck maps and normal character rules. Ship batteries and hazards can act on initiative count 20 or when operated by characters.

Background Crew Battle

Once each ordinary combat round, resolve the crews in the background:

Each side rolls d20 + CQ.

Apply:

• +1 CQ for every full 10 active crew by which one side outnumbers the other;
• +1 CQ for every 10 trained guards or marines;
• −1 CQ when a ranking officer is defeated;
• −3 CQ when the captain is defeated or captured.

The difference between the totals is the number of casualties suffered by the lower side.

A crew normally surrenders when:

• it is outnumbered at least 3 to 1;
• its captain and ranking officers are defeated;
• escape is impossible and continued resistance has no objective.

The PCs fight important officers, secure objectives, cut lines, seize the helm, protect cargo, or compel surrender while the mass battle occurs around them.

Undercrewed Ships

Compare current able crew with the Sailing Crew requirement.

Able Sailing Crew	Effect
100% or more	Full Orders and normal operation
75–99%	Maximum Orders −1
50–74%	Maximum Orders −2; Helm Checks have disadvantage
Below 50%	Maximum 1 Order; Speed halved; cannot operate Heavy Cannon, Culverin, Trebuchet, or another 3-Mount weapon

Weapon crew are checked separately. A battery without its minimum crew cannot Reload, Aim, or Fire.

Automation reduces the Sailing Crew requirement but not weapon crew.

Spells and Character Actions

Range

• Ranged spells and personal attacks against another ship normally require Short range.
• A spell with a genuinely exceptional range may function at Long range at the GM’s discretion.
• Teleportation, flight, swimming, and planar movement follow their normal rules.

Area Effects

An area spell may target the deck, crew, rigging, or Hull.

• Against the Hull, use actual damage as Salvo.
• Against creatures, use standard 5e damage and saves.
• Against multiple ship targets, the GM may apply half damage to secondary components.
• Fire effects can trigger the Fire critical when the fiction warrants it.

Mending

The ordinary mending cantrip can repair rope, sailcloth, a broken line, or one simple Damaged rigging result. It cannot restore Integrity or rebuild a Disabled major component.

NPC Break Conditions

Every important NPC ship should have a Break Condition written on its combat card.

Doctrine	Typical Behavior
Merchant	Attempts Flee after the first Integrity loss; surrenders if Grappled and clearly overmatched
Smuggler	Flees if identified, cornered, or cargo is exposed
Pirate	Closes to board; flees at 2 Integrity if boarding is impossible
Privateer	Tries to disable and capture; disengages at 2 Integrity unless the prize is exceptionally valuable
Navy patrol	Fights until its mission fails, captain falls, reinforcement arrives, or it reaches 2 Integrity
Fanatic, construct, or undead	Fights to 0 Integrity unless commanded otherwise

Break Conditions are not arbitrary mercy rules. They express the enemy’s objective and prevent every encounter from becoming a race to complete destruction.

One-Page Flow of Combat

SETUP
1. Choose Extreme, Long, or Short range.
2. Record Integrity, Armor Integrity, CQ, Orders, batteries, Reload, and criticals.
3. Roll Helm initiative once. Winner chooses declaration order.
 
EACH ROUND
 
1. HELM
   Close / Flee / Evade / Hold Steady / Parting Shot /
   Hold Range / Ram / Grapple
   Opposed when objectives conflict.
   Speed Edge: +1 per 10 ft. faster, maximum +3.
 
2. ORDERS
   Fire battery (1)
   Aim battery (1)
   Reload one box (1)
   Brace (1)
   Damage Control (1)
   Emergency Repair (1, once per battle, costs 1 Supply)
   Prepare Grapples (1)
   Activate crew-dependent upgrade (1)
 
3. ATTACK
   One roll per battery.
   Short normal; Long and Extreme disadvantage.
   Battery Salvo = weapon Salvo × number of weapons.
   Below DT = 0 Integrity
   DT–49 = 1
   50–99 = 2
   100+ = 3
   Natural 20: +1 Integrity damage, maximum 3, and critical.
 
4. CONSEQUENCES
   Apply Armor Integrity, Integrity, criticals, Fire, and reload.
   At 2 Integrity: DC 15 CON sinking save when triggered.
   At 1 Integrity: DC 18 CON sinking save when triggered.
   At 0: foundering; sinks in 1d4+2 rounds.
 
5. END
   Did a ship escape, surrender, founder, or Grapple?
   If Grappled, switch to standard 5e combat immediately.