Naval Combat

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The following was adapted from Limithron's Guide to Naval Combat to fit my own sensibilities and the design philosophy of Nimble.

Ship Statistics

Speed

The number of 50ft hexes the ship can move a turn with favorable winds. Also the maximum number of 15 mile spaces a ship can travel a day. See the section on “Wind and Movement,” and “Ship Speed” in Sailing.

Armor

Represents the resilience of the ship’s hull. Any armor ignores damage bonuses, while Heavy armor additionally grants resistance to rolled damage.

Hit Points and Formula

The amount of damage a ship can take before it is Derelict. This number is scaled down by a factor 1:5 when compared to creature-scale encounters. See the section on “Dice and Scaling.” HP per level is also given for upgrade purposes.

Temporary HP

This is HP gained while performing repairs in combat. When added to a ship’s current HP, the result can never exceed the ship’s maximum HP. Subsequent actions may add to Temporary HP. Temporary HP lasts no longer than 12 hours.

Damage

The amount of damage the ship does with its primary weapons (typically Broadsides, with Round Shot). Range is listed under Ammunition.The first range increment lists the maximum range before the ship takes Disadvantage 1 on its attack; the second lists the hard maximum range of the weapons.

Morale

(NPC ships only) A score between 2 and 12 representing how likely the ship is to flee or surrender during combat.

Crew

The number of crew currently serving on the ship, and the maximum number the ship can accommodate. Crew numbers are not tracked for the purposes of ship combat but can be used for boarding and roleplaying.

Minimum Crew

The number needed to operate the ship without being Stressed. This is typically half of the ship’s maximum crew.

Captain

(NPC ships only) A notable figure captaining the ship. They typically include a static bonus to rolls made by the ship and/or a damage bonus.

Abilities

Special abilities unique to each ship. The most common are Weatherly and Sluggish.

Cargo

The number of cargo "slots" the ship has, ranging from 0-10. Cargo might have different value in different ports. Also included are the default Food and Water stores (typically enough for 12 days), and Repair Supplies (typically enough for 6 repair actions). NPC ships also typically include a Lockbox entry, listing currency held aside from the ship’s cargo (usually kept in a literal lockbox in the Captain’s cabin).

Dice and Scaling

(copied from Limithron’s Guide)

The dice rolls and statistics in this supplement are scaled by a factor of 1:5 when compared to creature scale combat. For example, a ship that has 10hp and deals 1d6 damage would have 50hp if attacked by a creature, and it would deal 1d6 x 5 damage. Any damage dealt to ships by creatures should be rounded down to the nearest 5, or you can track exact ship hit points by multiplying their base value by five. A fireball spell could hypothetically sink a rowboat or canoe in one shot, but a 1st Rate Ship of the Line could have 1,000hp!

Degrees of Success

The default difficulty for skill and ability checks during ship combat is DC 10. Checks are rolled by the acting Captain unless another character is at a corresponding Action Station. The GM can modify the DC based on conditions like rough seas, weather, surprise, terrain, or a crew that is inexperienced, wounded, or frightened. A result of 10 or higher represents a “basic” success on the test.

Ability checks that equal or exceed 22 are considered critical successes (in addition to “natural 20” results). Most combat actions specify additional effects that occur on a critical result.

Some actions also specify intermediate effects that occur on a DC 16-21 result, representing a degree of success between a “basic” and “critical” result.

Ship Abilities

This list of ship abilities is far from exhaustive.

Weatherly This ship does not decrease its max speed when sailing Close to the Wind in combat, and may turn 1 extra hex face when turning.

Sluggish This ship can only turn one hex face per turn in combat.

Runic Sails This ship loses Sluggish and increases its speed by 1.

Hardened This ship automatically succeeds on its first Morale check.

Snipers This ship does not reduce its range for its Fore/Aft weapons.

Movement and Position

Ship combat is played on a hex grid where each hex represents 50ft from center to center. Most ships will take up 1 to 3 hexes. They should be orientated with the center of the ship on the center of a hex with the bow and stern crossing perpendicular edges. A ship’s bow will only face one of 6 different hex directions. All turns are 60 degree rotations (one hex face) rotating around the center of the ship.

Moving a Ship

All ships, if they take no other move actions during a turn, move half their current speed directly forward. (A ship’s current speed depends on the wind’s direction in relation to the ship’s current facing). They do not do so if they are In Irons or Anchored.

Ships that are Anchored may not take (Sails) actions.

Wind and Movement

The wind direction is an important part of sailing. In combat, the wind blows in the same direction as during the same watch; see “Wind” on the Sailing page.

If the GM needs to randomly determine wind direction at any point, they may roll a d6:

Points of Sail

Ship sailing speeds depend on the angle of the wind. A ship's point of sail is determined at the start of its turn and does not change during its turn. If a ship starts its turn With the Wind and then turns Close to the Wind, it still gets its full movement that turn.

Note that Weatherly ships sail Full Speed even when Close to the Wind in combat.

Example: If the wind is coming from 1 (North), and the ship faces the same way, this ship is In Irons and cannot move (but may still turn with Come About). If the wind is coming from 2 or 6, it is sailing Close to the Wind and may only move half of its normal speed; at 3, 4, and 5 it would be With the Wind and can move its full movement.

Combat Rounds

Like creature combat, ship combat is organized into turns and rounds. Initiative is rolled for each ship, and the creatures on that ship all act on their ship’s turn. Independent creatures, like sea monsters or characters not on a ship, roll their own initiative.

Sailing is slow, and weapons take time to reload, but these rules are designed to be fast and fun. For the purposes of rules and action economy, a round of combat represents 6 seconds in the game world, though 30 seconds to 1 minute is a more thematic representation.

Combat Round

1. Roll Initiative. Declare the Lookouts, if any. Lookouts (or Captains) roll initiative.


2. Take turns. Each ship takes a turn in initiative order.
   
   
   • On a ship’s turn, characters may choose one Action Station based on the Captains chosen actions, and they may choose a different station each turn.
   
   
   • On each turn, the ship takes 1 Move action, 1 Primary action, and 1 Auxiliary action. Alternatively, they may replace both their Primary and Move actions with 1 All Hands action.


3. Begin the next round. Repeat the steps until the combat is over.

Nearly all actions below call for a particular skill check from a particular crew station. One PC may act in one crew station at a time, though they may change their station round to round. Riggers, Carpenters, and Lookouts may have multiple PCs manning that station during the same turn. Whenever a Rigger, Carpenter or Lookout rolls a skill check, additional PCs in the same station each grant Advantage 1 to the roll.

The skills called for in each action represent the typical approach taken by sailors to accomplish their responsibilities. Particular circumstances may allow for an unorthodox application of a skill not specified; this is left to the DM to adjudicate. Also, a DM may allow a particular player character with unique abilities to pitch particular uses of skills outside of their typical context. For example, a dryad Carpenter who can feel and manipulate the ship’s wooden hull might roll Naturecraft for a repair action.

If a PC is not manning a particular station, the Captain may substitute an Influence check for any skill check called for. The Captain may not achieve anything higher than a basic (DC 10) success on this check.

Roll Initiative!

Initiative is rerolled each round of combat. Each ship rolls a d20 and adds its captain’s KEY stat. This roll may alternatively be made by the ship’s declared Lookout using their Perception or Insight skill. Additional Lookouts each grant Advantage 1 to this roll.

Ship Actions

At the beginning of their turn, each ship takes 1 Movement action. They then may take 1 Primary and 1 Auxiliary action in any order.

Movement Actions

Each Movement action is taken at the start of each ship’s turn. Actions with the (Sails) tag may not be taken when the ship is Anchored.

Stuns'l's Out! (Sails) The Rigger rolls a DC 10 Influence, Might, or Finesse check. On a success, the ship moves double its full speed in its current direction. On a 22+/critical result, the ship moves double its full speed plus up to 3 hexes instead. On a failure, the ship moves its full speed and then drifts two hexes with the wind.

The ship may not turn at any point during this movement.

Full Sail! (Sails) The Pilot rolls a DC 10 Might or Finesse check. On a success, the ship may move its full speed in its current direction, and may turn 1 hex face (or 2 if Weatherly) during or after this movement. On a 22+/critical result, the ship may turn 2 hex faces (3 if Weatherly) instead. On a failure, the ship moves half its speed and then drifts one hex with the wind.

Reef the Sails! (Sails) Either the Pilot or the Rigger rolls a DC 10 Might or Finesse check; the Rigger may instead roll Influence. On a success, the ship may move up to half its full speed, and may turn up to 2 hex faces (3 if Weatherly) during or after this movement. On a failure, the ship drifts one hex with the wind instead.

Drift (Sails) If no other Movement or All Hands action is taken on its turn, the ship automatically moves half its speed in its current direction without turning.

Note that if a ship is In Irons, its speed for any (Sails) action it takes is 0. For example, if it Reefs the Sails, it moves 0 hexes and then may turn up to 2 hex faces (3 if Weatherly), removing In Irons and allowing it to move on its next turn.

If the ship is Anchored, the following Move action becomes available:

Cut and Run! The ship loses its anchor, is no longer Anchored, and may immediately take one (Sails) Move action.

Note the Raise the Anchor Full Hands action which also removes the Anchored condition from the ship.

If the ship collides with another ship during its move, it takes its primary attack die as damage, and deals half that damage to the other ship. (See the Ram! All Hands action, which modifies this rule significantly).

Primary Actions

This action may be taken before or after any chosen Auxiliary action, if any.

Fire! (Attack) The Gunner rolls the ship’s primary damage dice. On a Broadside attack, roll the ship’s full primary damage dice. On a Fore-/Sternchaser attack, roll 1 die lower than the ship’s primary damage dice.

The Gunner may choose to Take Aim before rolling damage by making a DC 10 Finesse or Perception check. On a success, grant the ship either Advantage 1 on all attacks, or a damage bonus equal to 1/2 their character level, for this turn. On a 22+/critical result, they instead grant either Advantage 2, or a damage bonus equal to their character level.

Change Ammunition. The hull crew changes the ammunition type currently readied for all weapons.

Each weapon arc (Fore, Aft, Port, Starboard) typically has one ammunition type loaded at a given time. The Change Ammunition action may change the ammo type loaded for all four weapon arcs, and they need not change to the same ammunition for all four. Unless specified by players, the DM may assume all weapons are readied with Round Shot at the beginning of combat.

Combat Repair (Repair) The Carpenter makes a DC 10 Examination or Might check. On a success, they grant the ship temporary HP equal to its maximum primary damage die (1d8 would grant 8, 3d4 would grant 12, etc).

On a 16-21, they add KEY to the temporary HP granted, and on a 22+/critical result, they add twice that amount.

Derelict Repair (Repair) If the ship is Derelict, the Carpenter makes a DC 10 Examination or Might check. On a success, they grant the ship 1 HP on a successful check (thereby removing the Derelict condition). On a 22+/critical result, they grant the ship 1d6+KEY HP instead.

Brace! The Lookout makes a DC 16 Perception or Insight check. On a success, they increase the ship’s armor by 5 until the end of the next round. On a 22+/critical result, they instead increase it by 10.

Auxiliary Actions

This action may be taken before or after a chosen Primary or All Hands action, if any.

Push the Crew. The captain makes a DC 10 Influence check. On a success, the ship gains one extra Primary or Auxiliary action this turn. The ship loses that same action on its next turn unless the captain rolled a 22+/critical result.

Raise Morale. The Bosun makes an Influence skill check. On a success, they grant all of the ship’s attacks and skill check rolls +1 this turn per degree of success (+2 on a 16-21, or +3 on a 22+); or temporarily remove the Stressed condition from the ship for one round per degree of success (two rounds on a 16-21, or three on 22+).

Cast a Spell. A crewmember with access to spellcasting may cast a spell with a casting time of 1 Auxiliary action.

Throw the Grapples! If an enemy ship is in an adjacent hex, the Rigger may make a DC 10 Influence, Might, or Finesse check. On a success, the ship turns parallel and both ships become Anchored, allowing for secure boarding actions (i.e. a transition to 5-foot scale combat).

All Hands Actions

This action takes the place of a Move and Primary action together. The ship may still perform an Auxiliary action before or after this action. If this action is not a Sails action and the ship is not Anchored, the ship moves half its speed in its current direction after this action without turning.

Ram! (Sails) Either the Pilot or the Rigger rolls a DC 10 Might or Finesse check; the Rigger can instead choose to roll Influence. Move the ship up to its full speed. On a success, if the ship’s bow touches another ship at the end of this move, deal the ship’s primary attack damage. Add a damage bonus equal to half the number of hexes moved during this turn, rounded up. (No damage is dealt to the ramming ship).

On a 16-21 result, the ship gains Advantage 1 on the damage roll. On a 22+/critical result, it gains Advantage 2 instead. On a failure, treat this as a normal ship collision instead. 

Double Broadside! (Attack) The ship takes the Fire! action twice. It may not fire from the same side both times (Fore, Aft, Port, Starboard). (The ship then moves half its speed in its current direction without turning).

Drop Anchor! Apply the Anchored condition to the ship.

Weigh Anchor! Remove the Anchored condition from the ship. If the ship is Weatherly, it may immediately turn 1 hex face. (The ship then moves half its speed in its current direction without turning).

Arc of Fire

In the age of gunpowder weapons, most ships carried the majority of their arsenal along the side of the ship, requiring the vessel to maneuver to the sides for most cannons to have a shot.

Broadside refers to this area. A Broadside attack may hit a ship directly in line perpendicular to the ship’s movement at the first range increment, or one adjacent hex fore or aft. If a ship attempts an attack at the second range increment, they may hit an arc from two spaces fore or aft.

Example The Iron Pantaloon, below, has a standard range increment of 6/12. It may fire its Broadside cannons at the Dewey Dumbass, rolling its attack as normal. It may not, however, fire upon the Sly Cooper. It may instead choose to fire upon the Far Fetched, but it will take Disadvantage 1 on its attack.

Other attacks can only fire Fore & Aft. Typically these attacks deal 1 die rank lower than its primary attack (so a ship which deals 1d8 primary damage would deal 1d6 damage with its chase guns; a ship dealing 2d6 damage would deal 2d4).

Fore and Aft attacks have half the range of Broadside attacks—thus, a Fore attack with Round Shot (6/12) has a maximum range of 6 hexes.

Ship Combat Spells

One particularly useful spell a character may cast during combat is included here.

Command the Wind
Wind Cantrip, 3 actions
A character of the specified level who has access to the Wind spell list may spend mana to influence the winds in the following ways on their turn:

• 2 mana (Level 2) Change the wind direction by 1 hex face for their ship only.
• 4 mana (Level 7) Change the wind direction by 1 hex face for an enemy ship within 10 hexes.
• 10 mana (Level 12) Change the wind direction by 1 hex face for the entire battlefield. (Level 17) You may exempt a number of ships on the battlefield from this change equal to your KEY stat.

Wind changed in this way may be further changed and maintained with concentration over multiple turns. If multiple creatures are attempting to influence the wind in the same area, they roll opposed KEY checks on each turn to gain or maintain control of the winds.

Dropping concentration on this spell immediately reverts the wind to its natural direction.

For example, on a naval battlemap with flat-top hexes, the wind is currently blowing due North. If a wind magic-user spends 4 mana to change the wind from North to Southwest on turn 1 for their own ship, they may subsequently concentrate on this ability on turn 2 and choose to: maintain the wind in that direction; change the wind direction back to North; or change the wind direction to the Southeast.

Morale

Note: This is a GM-only mechanic. Players (particularly Captains) should be encouraged to roleplay out a loss of morale among the crew they command and consider a fighting retreat depending on the circumstances of the combat. Players do not track this mechanic.

Each NPC ship is assigned a Morale score between 2 and 12, though most will fall between 4 and 9. This score represents how easily that ship crew’s morale would break during battle, causing its members to flee or surrender. 2 represents being utterly cowardly (or totally uninvested), likely fleeing at the first threat of violence; 12 represents being so hardened (perhaps supernaturally so) that they will fight to the last breath.

At the following three points in the battle, morale will be checked by rolling 2d6:

1. First Sight; that is, the players ship is sighted on the horizon and identified as hostile;
2. First Blood; the first time the ship takes damage;
3. Decimation; when the ship has lost half or more of its HP.

First Sight is rolled with Advantage 1, and Decimation is rolled with Disadvantage 1. If the result exceeds the ship’s morale score, that faction will either seek to retreat or surrender. If the result is higher than the morale score by 4 or more, the crew may devolve into a disorganized panic.

Bonuses or penalties between +2 and -2 can be applied to each morale check depending on the circumstances of the battle at that moment.

Ship Conditions

In Irons

A ship is In Irons if its bow is facing directly against the wind. Its speed is 0.

Anchored

A ship that is Anchored does not move during its turn. It may not take any (Sails) actions.

Stressed

A ship is Stressed when it has less than half of its starting hit points. A ship is also Stressed if it has less than its listed minimum crew. A Stressed ship imposes Disadvantage 1 on all its attacks and skill checks.

The Bosun may attempt the Raise Morale Auxiliary action to temporarily remove this condition in combat.

Derelict

A ship gains the Derelict condition when it has 0 hit points. Its speed is 0, and it may only spend its Action Points in combat on (Repair) actions. A ship loses Derelict when it gains at least 1 hit point (Gaining temporary hit points does not remove this condition).

Drifting. A Derelict ship drifts one hex each turn in the direction of the wind.

Sinking. Every time a Derelict ship takes additional damage, it must make a sinking saving throw. Roll a d20. If the roll is 10 or higher, the ship does not sink. Otherwise it fails and the ship sinks into the water.

If a Derelict ship is hit with a critical hit that would reduce its HP, it immediately fails this saving throw. (If a critical hit would reduce only a ship’s temporary HP, it does not automatically fail).

Ammunition

Ships typically carry round shot (cannon balls) by default, but other types of ammo may be purchased from shipwrights. Additional ammunition ideas: canister shot, heated shot, spider shot, smoke bombs, poisonous canisters, random cargo (fork and knives), cursed bones, and magical ammo.

Round Shot
Round shot, often simply called "cannon balls", are accurate and deadly at long range. They can cause massive damage against their targets and are used in all types of naval warfare, especially when the primary objective is sinking the enemy.

Range. 6/12

Chain Shot
Chain shot is made by attaching two cannonballs—or two halves of a single cannonball—together with a chain. It is designed to attack a ship's masts and rigging and is typically used to slow ships down.

Range. 4/8
Target Masts & Rigging. Attacks made with Chain Shot deal half damage, rounded up. Any ship that has taken damage from Chain Shot moves at half speed (rounded up) until the end of its next turn.

Critical Hit. When a Chain Shot attack scores a critical hit, the target ship may not take any (Sails) actions other than >Drift until the end of its next turn.

Grape Shot
Grapeshot is made by filling a bag or hollow ball with small round metal balls, similar to shotgun shells. It is very effective against creatures but less so against a ship's hull.

Range. 4/8
Target Crew. Attacks made with Grapeshot deal half damage rounded up. Any ship that has taken damage from Grape Shot gains Disadvantage 1 on Skill checks. It may take either a Primary or an Auxiliary action on its turn, until the end of its next turn.

Critical Hit. When a Grapeshot attack scores a critical hit, the target ship may only take 1 action on its next turn, and all skill checks suffer Disadvantage 2 instead.