Ship Combat Rules

Introduction

This supplement is designed to provide an easy to learn, adaptable rules set for ship to ship combat in 5th edition. While these rules and ship stats are designed with gunpowder and cannons in mind, they can easily be adapted to any fantasy setting by rebranding or modifying attacks.

The Basics

• A ship may move up to its full movement each turn
after adjusting for the wind.
• HP and damage are scaled down for speed and simplicity by a factor of 1:5.
• Combat is on a hex grid (1 hex =50ft).
• Wind matters, but it’s simple.
• Ships may turn, and typically they must move at least 1 space.
• Initiative is rolled each round, but only ships and solo creatures roll. Passengers act on their ship's initiative.
• Each ship has a Captain. That captain assigns Action Points for their ship at the top of each round.
• Most actions require the ship to make an ability or skill check; characters can choose Action Stations on their turn to help with these checks.

Ship Statistics

Ship statistics are adapted from 5e monsters, but they have been mutated to be more applicable for inanimate vehicles. Some stats, like Constitution, represent a ship's physical construction, while others represent the crew’s skill

Strength. The potency of a ship’s attacks. This could represent the size of its siege weapons or the precise aim of a well trained crew. Uses: damage roll modifier.
Dexterity How maneuverable a ship is. Smaller ships are more dexterous. Uses: initiative modifier, “Come About” action.
Constitution Construction quality and fortitude of a ship. Uses: hit point calculation.
Skill. Represents the quality of the crew and their leadership. Uses: To Hit, “Full Sail” action, "Repair" action.
AC. Represents the resilience of the ship’s hull or its small size and agility.
Speed. The number of 50ft spaces the ship can move a turn with favorable winds. Also the maximum number of 25 mile spaces a ship can travel a day at a normal travel speed. See the section on “Wind and Movement.”
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”.
Crew. The minimum number of crew needed to operate the ship without being Stressed. Crew numbers are not tracked for the purposes of ship combat but can be used for boarding, Mob Combat, and roleplaying.
Max Crew. The maximum number of crew and passengers this ship can carry comfortably on long voyages. Most ships can carry double this number on short voyages such as raids or refugee operations.
Cargo. The number of cargo "slots" the ship has. Each slot represents 50 tons of product.
Size Ships have their own scale separate from creatures. Uses: hit point calculation, ramming.

Ship Sizes

Size	Space	Hit Die	Hexes	Example Ships
Tiny	<30ft	d4	1	Rowboat, canoe
Small	<50ft	d6	1	Longboat
Medium	<75ft	d8	1	Sloop
Large	<100ft	d10	1x3	Brigantine
Huge	<125ft	d12	1x3	Galley
Gargantuan	>125ft	d20	3x5	Ship of the Line

Dice Scaling

The damages rolls and hit points 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!

Skill and Ability Test Difficulty

The default difficulty for skill and ability checks during ship combat is DC 13. Checks are rolled by the acting Captain unless another character is at a corresponding Action Station. The DM can modify the DC based on conditions like rough seas, weather, surprise, terrain, or a crew that is inexperienced, wounded, or frightened.

Movement and Position

Ship combat is played on a 1” 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) from the center of the ship.

Moving a Ship

• A ship must move its full movement after adjusting for wind (exceptions: In Irons, Anchored).
• A ship must move directly forward to the space in front of its bow.
• A ship may rotate twice (rotate one hex face or 60º) at any point before, during, or after its movement, but no ship may turn more than once per space.
• Ships that are In Irons may not move forward but may still rotate once.
• Ships that are Anchored cannot move or turn.

Wind and Movement

The wind direction is an important part of sailing. It affects a ships ability to move and can give the group a thrill in the extra element of strategy it adds, especially when a spell caster may be able to alter conditions. If the direction of the wind is unknown at the start of naval combat, the DM can roll the following chart to determine its direction.

Wind Direction

d6	Wind Direction
1	North
2	Northeast
3	Southeast
4	South
5	Southwest
6	Northwest

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.

Points of Sail

Point of Sail	Ship Speed
With the wind	Full speed
Close to the wind	Half-speed rounded down (min. 1")
In Irons	Speed 0" (can still turn one)
Anchored	Speed 0" and cannot turn

Example: If the wind is coming from 1 (North), this ship is In Irons and cannot move (but may still turn once). 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.

Anchoring a Ship

A ship that is Anchored cannot move or turn, and has a max speed of 0. In an emergency the crew can Cut and Run.

Drop Anchor. Cost: All of a ship's action points. The crew lowers the anchor(s) and the ship's speed is reduced to 0.
Weighing Anchor. Cost: All of a ship's action points. The crew raises the ship's anchor(s). The ship's max speed is reduced to half for this turn.
Cut and Run. (Cost: 0 Action Points) The ship is no longer anchored, but will drift until new anchors are acquired! The ship's max speed is reduced to half for this turn.

Arc of Fire

In the age of gunpowder weapons, most ships carried the majority of their arsenal along the side of the ship, referred to as Broadside. Vessels needed to maneuver to port or starboard in order for most cannons to have a shot a target they were chasing. Some other attacks, like the 1st Rate’s Chase Guns, can only fire Fore & Aft.

The Order of Combat

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 that are not on a ship roll their own initiative.

In standard combat, a round of fighting represents 6 seconds. That being said, sailing is slow, and cannons take time to reload. Because of this, a round of naval combat represents 30 seconds, instead. It is important to keep this in mind while strategizing, especially for spell casters considering spells with a time duration.

Combat Round Step by Step

1. Captain's Phase. Captains choose their ship’s actions, and they may roll to Push the Crew.
2. Declare Lookout & Bosuns. Any PCs may declare these stations now. Bosuns may try to Raise Morale.
3. Roll Initiative. Lookouts (or Captains) roll initiative, then apply Lookout & Bosun modifiers.
4. Take Turns. Each ship takes a turn in initiative order. On a ship’s turn, characters may take actions in any order they see fit. Each may claim an Action Station based on the Captains chosen action points, and they may choose a different station each turn. They may also choose another action like casting a spell. Ships and characters may Ready actions to trigger anytime before the ship’s next turn.
5. Begin the Next Round. Repeat the steps until the combat is over.

Captain's Phase

During this phase, each ship’s Captain decides what actions the ship will take. Each ship has a set number of Action Points and the Captain can spend any of these to assign actions for the characters and crew on board to carry out later in the turn. Any actions not carried out by the other characters will be rolled by the Captain. The captain may also roll to push the Crew (see the section on the Captain Action Station).

Initiative Phase

Initiative is rerolled each round of combat. After all Captains have decided their ships’ actions for the turn, each ship rolls a d20 and adds its Dexterity modifier. This roll is made by the Captain unless the ship has a Lookout. See the section on “Action Stations”.

Ship's Turn

On a ship’s turn, the Navigator or Captain may move a distance up to the ship’s speed and make two rotations. The characters may take any actions that the Captain spent action points on at the beginning of the round, plus any other actions or bonus actions like the Bosun’s Raise Morale ability or casting a spell. After the characters have gone, the Captain rolls for any actions the characters didn’t complete. These actions may be taken before, after, or at any point along the ship’s movement.

Characters may also Ready actions (i.e. wait for a target to be in range.) If the ship holds any Fire Cannons! actions, it may make all of its attacks when the Ready action is triggered, not just one attack (as you would during character combat).

Action Point actions are optional and the characters and crew do not have to take actions unless they or the captain want to, but the ship make not change what actions it choose until the beginning of the next round.

Ramming and Collisions

Ramming

At the beginning of the turn, a captain may spend all of a ship’s Action Points to declare a ram. On that ship's turn, if it ends its movement with any of its forward three sides touching another ship, it rams. Both ships roll their base hit die and the ship that initiated the ram adds +1 to their roll for each space traveled since the beginning of its turn. Deal that much damage to the other ship. In addition, each ship that was part of a Ram since the start of its last turn is considered to be Anchored (speed 0, can't turn) for 1 turn.

A ship with a naval ram installed takes half damage from the opposing ship.
If for some reason the ramming ship cannot get to a space adjacent to another ship, it does not ram and its Action Points are lost.

Example: A brigantine (7d10+14 hp) rams into a sloop (6d8+6 hp). The brigantine travels 3 spaces before making contact, so it will deal 1d10+3 damage to the sloop. The sloop will deal 1d8 damage to the brigantine. Both ships are considered Anchored for their next turn.

Collision

If a ship collides with something (shoals, a large rock or island, another ship unintentionally) it will take damage equal to one of its hit dice plus the distance it traveled since the start of its last turn. In addition, each ship that was part of a Collision since the start of its last turn is considered to be Anchored for 1 turn. The DM might also deal damage to the object the ship collided with, and might impose other effects like the ship being stuck until a Repair action is taken.

Ship Action Summary

Action	AP Cost	Description	Action Station
Fire Cannons! (Broadside)	1	Launch a volley of cannon fire with primary attack at a target in the ship's Broadside arc. 6"/12" Range	Gunner
Fire Cannons! (Fore/Aft)	1	Launch a volley of cannon fire with secondary attack: roll one die rank lower (ie. d4 instead of d6, d6 instead of d8, etc.). 3"/6" Range	Gunner
Change Ammo Type	1	Switch out the type ammo used during the Fire Cannons! action.	Gunner
Repair	All	Skill Test: Recover hit points equal to primary attack damage or remove the Derelict condition. May only be taken when Stressed.	Carpenter
Full Sail	*	Skill Test: Move one extra space this turn. It costs 1 AP for tiny to large ships and 2 AP for huge and gargantuan ships.	Rigger
Come About	*	DEX Test: One extra rotation this turn. It costs 1 AP for tiny to medium ships, 2 AP for large and huge ships, and 3 AP for gargantuan ships.	Navigator
Ram	All	Ram if touching another ship. Both ships deal damage equal to each other equal to 1 hit die and are considered Anchored. Ramming ship adds distance traveled to damage.	-
Drop Anchor	All	Speed 0 and Anchored.	-
Weigh Anchor	All	Speed 1/2 and no longer Anchored.	-
Cut and Run	0	Speed 1/2, no longer Anchored, but will drift when stopped	-

Character Actions

Each turn, a character may spend their action to claim an Action Station (PCs still get a bonus action, free action, and reaction). Choosing a station is optional and they can be chosen again each round. Any actions that are not covered by a PC are rolled for by the Captain using the ship’s stats (but without any Sailing Dice).

Sailing Dice

Most Action Stations allow each character to add a d4 Sailing Die to one of the ship’s checks.

Action Stations

Captain

Limit: 1/ship, required
Each ship must have an assigned Captain. At the beginning of the round, the Captain chooses actions for each of the ship’s action points. Captains that choose the Fire Cannons! action only need to decide how many points to allocate when choosing the action. The attacks used and their targets may be chosen on the ship's turn.

Push the Crew. During a time of need the Captain may push the crew to their limits. As a bonus action, the Captain may attempt an Intimidation or Persuasion check. On a success, the ship gains one extra action point this turn but loses one action point next turn. A Captain may not attempt to push the crew two turns in a row.

Navigator

Limit: 1/ship
The Navigator moves the ship's token and makes the roll if the ship is attempting to Come About (DC 12), adding the ship’s Dexterity modifier and their Sailing Die (d4) to the total. The Navigator also makes any checks required to navigate terrain or obstacles.

Lookout

Limit: 1/ship
Before initiative is rolled each round, any PC may spend their action to become the Lookout. The Lookouts roll initiative for the ship, and add or subtract their Sailing Die from the result. Ships with Lookouts get +1 AC.

Bosun

Limit: 1/ship
This station may be claimed at any time, including before initiative has been rolled.

Raise Morale. As a bonus action, the bosun may make an Intimidation or Persuasion skill check to choose one of the following: give all of the ship’s cannon attacks and skill check rolls +1 this turn, or temporarily remove the Stressed condition from the ship for one turn (ship can still Repair).

Gunner

Limit: 1 per cannon fire

The gunners choose weapons and targets and roll attacks, adding the ship's Skill modifier and Sailing Die (d4) to their attack roll. A gunner can only take command over one Fire Cannons! action. Therefore, if there is only one gunner, but two attacks, only the first cannon fire made by the gunner would receive the Sailing Die bonus. The other would be made by the Captain.
The gold cost for each cannon volley is determined by the type of ship (i.e. how many cannons it has) and can be found in the ship's stats.
Change Ammo Type. Instead of taking the Fire Cannons! action, a gunner can command the crew to change the cannons' ammo type to either round shot, chain shot, or grape shot (see Appendix B). New types of ammo might become available to you during your adventures.

Carpenter

No limit

The Carpenter rolls to Repair (DC 12) the ship, adding the ship's Skill modifier and Sailing Die (d4) to the total. The captain cannot use this action if there is no carpenter. There may only be a max of 2 carpenter's adding their sailing die to the Skill test.

Rigger

No limit

The Rigger rolls to go Full Sail (DC 12), adding the ship's Skill modifier and Sailing Die (d4) to the total. If there are multiple Riggers, only one makes the Skill roll but each adds their Sailing Die to the total.

Other Actions

Characters may take other actions like casting a spell, attacking another creature, swinging from the rigging, diving from a ship, etc. As you upgrade and modify your ship, other actions might become available to you (ex. installing a mortar or ballista on the ship's deck).

Ship Conditions

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 the required crew. A stressed ship has disadvantage on all attacks and skill checks. Only stressed ships may take the Repair action. The Bosun can take the Raise Morale action to attempt to temporarily remove this condition (the ship make still take the Repair action)

Derelict

A ship is Derelict when it has 0 hit points. Its speed is 0, it cannot rotate, and it may only spend its Action Points on the Repair action.

Drifting. The DM may choose to have a Derelict ship drift one space each turn depending on weather conditions.

Sinking. Every time a Derelict ship takes more than 5 points of 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, it immediately fails its Sinking saving throw.

Repairing. The only action a Derelict ship may take is Repair, which must be made at disadvantage. If the Repair action is successful, the ship loses the Derelict condition and regains 1 hit point (instead of the normal amount recovered by the Repair action).

Boarding. A ship that ends its turn adjacent to a Derelict ship may begin to board it. When this is done, naval combat ends and normal combat between the two ships' crews begins immediately unless some form of truce, negotiation, or surrender is struck.

Appendix A: Ship Stats

There are a large variety of ships that sail the seas of Sebai. As you encounter and learn about them, their stats and abilities will appear here.

Raft

Tiny Vessel

---

AC 16
Hit Points 3 (2d4 - 2)
Speed 2
Initiative +4

---

Strength +2; Dexterity +4; Constitution -1; Skill +0

---

Base Damage -
Abilities -
Crew (Min/Max) 1/2
Cargo 0
Action Points 1

Canoe

Tiny Vessel

---

AC 16
Hit Points 6 (4d4 - 4)
Speed 2
Initiative +5

---

Strength +2; Dexterity +5; Constitution -1; Skill +2

---

Base Damage -
Abilities Oars
Crew (Min/Max) 1/3
Cargo 0
Action Points 1

Rowboat

Tiny Vessel

---

AC 16
Hit Points 6 (4d4 - 4)
Speed 2
Initiative +5

---

Strength +1; Dexterity +5; Constitution -1; Skill +2

---

Base Damage -
Abilities Oars
Crew (Min/Max) 2/6
Cargo 0
Action Points 1

Tartane

Medium Ship

---

AC 11
Hit Points 33 (6d8 + 6)
Speed 6
Initiative +0

---

Strength +2; Dexterity +0; Constitution +1; Skill +3

---

Base Damage 1d8 + 2
Abilities Weatherly
Crew (Min/Max) 4/10
Cargo 1/2
Action Points 2

Ship Abilities

Below are descriptions for the various ship abilities:

Weatherly. This ship does not decrease its max speed when sailing Close to the Wind.

Oars. This ship may spend half of its action points (rounded down to a minimum 1) to travel 2 spaces in any direction. This is in addition to its normal movement and is not affected by wind.

Sluggish. This ship may only rotate once per turn (unless taking the Come About action).

Heavy Armor. This ship has Resistance against attacks that deal 10 damage or less.

Appendix B: 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), bones, and magical ammo.

Round Shot

Round shot, or simply "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. As listed on ship card (typically 6"/12")

Critical Hit. Critical hits function as normal: roll damage dice twice.

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. 3”/6”

Target Masts & Rigging. Attacks made with Chain Shot deal half damage (rounded down). Any ship that has taken damage from Chain Shot moves at half speed (rounded down, minimum of 1) until the end of its next turn.

Critical Hit. When a Chain Shot attack scores a critical hit, the target ship’s speed is 0 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. 3”/6”

Target Crew. Attacks made with Grapeshot deal half damage (rounded down). Any ship that has taken any damage from Grape Shot has disadvantage on Skill checks and has -1 action point (minimum of 1) until the end of its next turn.

Critical Hit. When a Grapeshot attack scores a critical hit, the target ship loses half of its action points (rounded down to a minimum of 1) until the end of its next turn.