Beleriphon
2017-03-24, 04:36 PM
So, I'm working on a naval combat system Fifth Edition D&D. I'm vacillating between how much detail I want, what broad historical time periods to include and whether to actually include airships. So give some ideas about what you think, and in general what isn't clear in the follow. It is very much a work in progress, and doesn't include any actual ship stats just yet since I wanted to hammer down what the system is supposed to do before building stats for ships.
Introduction
Clashes between ships have been a staple of armed combat throughout human history. Although the earliest boats have generally been little more than a way to transport people to another place over water as history progressed vessels have become larger and
Starting Combat
The Line of Battle
A typical ship battle is an encounter between two sides, a series of traded attacks, evasive manoeuvres, ramming, and spellcasting. The game organizes the chaos of a naval battle into a cycle of rounds and turns. A round represents about thirty seconds in the game world. The reason for the lengthier time frame than combat between individual creatures is that coordinating a crew, aim and reload weapons, and bringing spellcasters into range takes much longer on a ship than it does for at individual level. During a round, each participant in a battle takes a turn. The order of turns is determined at the beginning of a naval battle, when each ship rolls initiative. Once everyone has taken a turn, the fight continues to the next round if neither side has defeated the other.
Ship Battles Step by Step
Determine surprise: The GM determines whether anyone involved in the combat encounter is surprised.
Establish positions: The GM decides where all the characters and monsters are located. Given the ships’ stated positions in the an area the GM figures out where the adversaries are how far away and in what direction.
Roll initiative: Each ship involved in the combat encounter rolls initiative, determining the order of combatants’ turns.
Take turns: Each participant in the battle takes a turn in initiative order.
Begin the next round: When everyone involved in the combat has had a turn, the round ends. Repeat step 4 until the fighting stops.
Surprise!
An orcish pirate ship glides out of the fog and attacks a dwarven merchant galley. A dragon turtle swims up beneath a knarr, unnoticed by the crew until the dragon turtle blasts the deck with scalding steam. In these situations, one side of the battle gains surprise over the other.
The GM determines who might be surprised. If neither side tries to be stealthy, they automatically notice each other. Otherwise, the GM compares the Dexterity (Stealth) checks of anyone hiding with the passive Wisdom (Perception) score of each creature or crew rating on the opposing side. Any crew or monster that doesn’t notice a threat is surprised at the start of the encounter.
Special: Creatures and characters proficient with water vehicles can instead make Dexterity checks and add their proficiency bonus rather than making Dexterity (Stealth) checks.
If your ship is surprised, it can’t move or take an action on its first turn of the combat, and you can’t take a reaction until that turn ends. A ship’s crew in a flottila can be can be surprised even if the other crews aren’t.
Initiative
Initiative determines the order of turns during ship battle. When a battle commences the pilot of each ship makes a Dexterity check to determine their ship’s place in the initiative order. A pilot proficient with water vehicles can add their proficiency bonus to the Dexterity check to determine initiative order.
Each member of a ship’s crew takes their turn at the same point in the initiative order. This allows each member to coordinate their actions with each other.
Characters on Ships
Roles
Characters on a ship can fulfill one of several rolls which will determine what they can do on board the ship. A character can fill any number of rolls, so long as they can reach all parts of the ship necessary to fulfill that role, or at least be able to shout orders at the crew who assist with that role’s actions.
For example a knarr typically has a navigator, a pilot, and two dozen rowers. A character could be both navigator and pilot, but would find it impossible to steer a ship while also acting as an oarsman. While a larger vessel such as a caravel has a crew of nearly one hundred but still only has one captain, one pilot, one navigator, and so on.
Captain: The captain of a ship is in charge of the overall operation and function of the ship. This role involves the overall command of a vessel as well as determining the overall tactics in combat. Some navies leave all disciplinary action at discretion of the captain, and and often refer to the captain Master-and-Commander. A ship may only have one captain.
Pilot: The pilot of a ship is directly responsible for steering the vessel both in and out of combat. A ship may only have one pilot at a time.
Navigator: The ship’s navigator plots course when not in combat. While in combat the navigator keeps the crew working the sails, oars or other means of propulsion. A ship may only have one navigator at a time.
Gunner: A ship’s gunner is in charge of a crew of two or three sailors that loads, aims, and fires a particular weapon. A ship may have as many gunners as there are weapons on board.
Carpenter/Enginee]r: The carpenter position onboard a vessel is responsible for repairing damage and maintaining the integrity of the ship and her parts. A ship may only have one carpenter or engineer.
[B]Other crew: Other members of the crew offer supporting roles to the ship’s main roles as well as providing support through their own abilities, skills, or spell casting. These roles can involve healing the injured, fighting boarders, or assisting other roles through the use of the help action.
Passenger: Passengers have no formal role on board a ship. However they are capable of stepping and filling any role, provided the crew is willing to let them.
Actions in Combat
Normal Actions
On a ship’s turn either the pilot or navigator can move the ship a distance up to the ship’s speed. Each crew member can also take one action. The navigator or pilot decides whether to move first or have the crew take their actions action first. The ship’s speed is noted with the ship’s statistics. The only limitation on a ship’s movement is that it cannot move immediately back into a space it just left.
The most common actions you can take are described in the “Actions” section. Many class features and other abilities provide additional options for your action.
You can forgo moving, taking an action, or doing anything at all on your ship’s turn. If you can’t decide what to do on your turn, consider taking the Dodge or Ready action.
Bonus Actions
Various class features, spells, and other abilities let you take an additional action on your turn called a bonus action. The Cunning Action feature, for example, allows a rogue to take a bonus action. You can take a bonus action only when a special ability, spell, or other feature of the game states that you can do something as a bonus action. You otherwise don’t have a bonus action to take.
You can take only one bonus action on your turn, so you must choose which bonus action to use when you have more than one available.
You choose when to take a bonus action during your turn, unless the bonus action’s timing is specified, and anything that deprives you of your ability to take actions also prevents you from taking a bonus action.
Reactions
Certain special abilities, spells, and situations allow you to take a special action called a reaction. A reaction is an instant response to a trigger of some kind, which can occur on your turn or on someone else’s. The opportunity attack is the most common type of reaction.
When you take a reaction, you can’t take another one until the start of your next turn. If the reaction interrupts another creature’s turn, that creature can continue its turn right after the reaction.
Breaking Up Your Move
You can break up a ship’s movement on your turn, using some of its speed before and after other actions. For example, if the ship has a speed of 300 feet, it can move 100 feet, characters can take their actions, and then the ship can move another 200 feet.
Using Different Modes of Travel
If your ship has more than one mode of travel, such as sailing and a flying, you can switch back and forth between your modes of travel during your ship’s move. Whenever you switch, subtract the distance you’ve already moved from the new speed. The result determines how much farther you can move. If the result is 0 or less, you can’t use the new speed during the current move.
For example, if you have a sailing speed of 300 and a flying speed of 600 because the ship is also a blimp, the ship could fly 200 feet, then sail 100 feet, and then take off into the air to fly 300 feet more.
Other Activity on Your Turn
There are a number of actions that a character can take their turn. Some of these actions are restricted to characters fulfilling a specific role onboard a ship. The following list is extensive although not exhaustive, if you wish to attempt something not included ask your GM and determine what checks and type of action might be required.
All out Movement: This requires the navigator’s bonus action. As a bonus action after using the Increase Speed action the ship may move up to its normal speed. However, on the following turn its speed is reduced to half of its normal speed.
Attack with a Ranged Weapon: Any crew member that has not otherwise used their action can attempt this action. You can attack an opposing vessel or her crew with your personal weapons as long as the other ship is in range.
Attack with a Ship Weapon: Requires the gunner’s action. You can attack an opposing ship or creature with one of your ship’s weapons.
Weapon Batteries
At battery is a group of up to six of the same weapon. No Help action is required to receive the benefit of the Help action of another gunner. Additionally each point the attack roll exceeds the target’s Armour Class another weapon strikes the target adding a +1 die to the damage. Add this die before adding any other multipliers. Ships armed with weapon batteries have this information in their statistics already, although each weapon can still be fired independently if need be.
Avoid Collision: As a reaction make a DC 15 Dexterity check with proficiency if you are proficient with water vehicles. On a success your ship takes only half damage from a collision or ramming. Only the pilot can take this action.
Cast a Spell: This requires your action. Cast a spell on a target in range. Any crew member capable of casting spells that has not otherwise used their action can use this action.
Defensive Manoeuvres: This requires your action. Upon initiating defensive manoeuvres you focus entirely upon steering the ship to avoid attacks. Until the start of your next turn, any attack roll made against the ship have Disadvantage. Only the pilot can use this action.
Help Action: You can lend your aid to another creature in the completion of a task. When you take the Help action, the creature you aid gains advantage on the next ability check it makes to perform the task you are helping with, provided that it makes the check before the start of your next turn. Any crew member that has not otherwise used their action can attempt this.
Increase Speed: This requires the pilot’s action. If you are proficient with water vehicles you can temporarily push your vessel beyond its normal limits. This can be either by rapidly changing the rigging on a sail, inspiring your rowers to greater feats of strength, or some other manner of producing greater speed. Make an Intelligence check plus your proficiency bonus against DC 15 to increase the speed of the ship by 50% rounded down, or rounded down to the nearest 100 feet if in combat.
Ram: This requires the pilot to take an action. The ship must move at least half of its speed in a straight line towards the target ship or creature and end its movement in the target’s space. A DC 10 Dexterity check is made with disadvantage, if the character making the check is proficient in water vehicles add their proficiency bonus to this check.
On a success the target is rammed and takes damage, and the ramming vehicle takes half of the listed damage rounded down. If the Dexterity check fails the both the target of the ram, and the ramming ship take normal damage. Damage is calculated by taking the non-combat speed of the ship and rolling that many d6s and multiplying the resulting damage by the Size Multiplier on Table X-X: Vessel Sizes. For example a huge ship with a 12kn (600 ft) speed rams a kraken. 12d6 x 4 is rolled for an average result of 168 points of damage. On a successful Dexterity check the ramming ship only takes half of that damage, on a failed Dexterity check both the kraken and the ramming ship receive the full amount of damage. Ships equipped with naval rams have special rules associated with ramming.
Ship Statistics
Attack
The attack statistic of a ship represents the ability of a the crew to operate the weapons and other attacks of the ship.
The basic attack roll of each ship is determined in the following way:
D20 + proficiency bonus + size modifier + other bonuses
Ship Size
The size of a ship indicates how large it is compared to other vessels. Due to how large even the smallest ships are compared to a typical creature ships a broadly classified into three categories: small ships, large ships, and huge ships.
Table X-X: Vessel Sizes
Vessel Size
Size Modifier
Average Length
Examples
Samll Ship
+0
40 to 100 feet
Knarr, caravel, cog
Large Ship
-2
125 to 200 feet
Brig, corvette, frigate
Huge Ship
-4
200 feet or longer
Galleon, Man o’ War
Tonnage
A vessel's tonnage represents how much cargo it can carry in general. Ships can carry this amount an travel at their normal speed. A vessel can carry double this value but it halves its speed as the much heavier load slows the ship.
Armour Class
All ships have an Armour Class. This value indicates how difficult a ship is to hit and damage with other ship based weapons.
The armour class of a ship is calculated as follows:
10 + size modifier + other armour
New weapon trait: Fixed Mount
Weapons with the fix mount trait deal triple damage against ships, objects, and creatures of huge and gargantuan size. Attacks made against creatures of large size and smaller are made with disadvantage on the attack roll.
Weapons
The weapons on a ship are used to engage in combat against other ships. Many ship based weapons have a new property: fixed mount.
All ship weapons have both a normal and long range value. Like creature scale weapons the normal range represents a weapon’s range in feet. Attacks made at long range have disadvantage on the attack roll and represent the weapon’s maximum range in feet.
Hit Points
Just like creatures ships have hit points. Hit points abstract a variety of the factors in ship to ship combat into one number that represents how close a ship is to being disabled.
When a ship reaches 0 hit points is it considered to be disabled. The crew cannot move the ship, nor can they fire the weapons. Although, it is still possible to repair the ship to working order either through magic, on board supplies, or outside assistance.
When a ship is reduced to its hit point maximum below 0 then it is destroyed and will completely sink within ten rounds of combat, or five minutes. Normally a ship in this condition is unable to be repaired, although the DM may allow extraordinary measures to stave off disaster or avert it completely.
Crew
This indicates the number of crew a ship requires to function in combat, as well the roles typically found on such a ship. Most ships have at least double the minimum crew needed to operate a ship in battle. It also indicates how skilled the crew is by presenting a generic proficiency rating for the crew as a whole. See the Crew Skill sidebar for more information.
Crew Cover
Most ships provide half cover to their crews and other creatures on their main decks. Creatures below deck typically have full cover, although some ships may provide only three-quarters cover to creatures below deck depending on the ship’s particular configuration.
Crew Skill
Rather than provide details for each individual member of a crew the following table provides a general overview of how skilled a particular crew is at operating their vessel. It can generally be assumed that the crew of a ship are proficient in the skills necessary to operate that vessel such as Strength (Athletics), Wisdom (Perception), water vehicles, and Wisdom (Survival)
The Default Ability Score is the score for any given skill check that isn’t otherwise listed for the crew.
Crew Skill Level
Skill Bonus
Default Ability Score
Untrained
+0
8
Green
+1
10
Skilled
+2
12
Veteran
+3
12
Expert
+4
14
Master
+5
16
Speed
Every ship has at least one speed rating. This determines how far a ship can move in each round of combat, much like character’s speed indicates how far a creature can move in each round of combat.
The speed of a ship indicates how fast a ship can travel in knots outside of combat. The second number in brackets is the number of number of feet a ship can move under normal circumstances in combat. Some abilities, spells, or manoeuvres may allow the ship to move faster, or slower than this rate. For example an elven caravel has a speed of Sails 13 knots (600 ft), meaning that in combat it travels at a rate of 13 knots (approximately 17 miles per hour) while it can use its sails, and roughly 700 feet per combat round while under sail.
Some ships may have more than one speed depending on how many means of propulsion they possess. No matter how many means of propulsion are used only the highest speed is counted if several are deployed at once. For example, a dwarven galley with speeds of Sail 8 knots (400 ft) and Rowing 11 knots (600 ft) will only use the rowing speed if both the sails and oars are used at the same time.
Introduction
Clashes between ships have been a staple of armed combat throughout human history. Although the earliest boats have generally been little more than a way to transport people to another place over water as history progressed vessels have become larger and
Starting Combat
The Line of Battle
A typical ship battle is an encounter between two sides, a series of traded attacks, evasive manoeuvres, ramming, and spellcasting. The game organizes the chaos of a naval battle into a cycle of rounds and turns. A round represents about thirty seconds in the game world. The reason for the lengthier time frame than combat between individual creatures is that coordinating a crew, aim and reload weapons, and bringing spellcasters into range takes much longer on a ship than it does for at individual level. During a round, each participant in a battle takes a turn. The order of turns is determined at the beginning of a naval battle, when each ship rolls initiative. Once everyone has taken a turn, the fight continues to the next round if neither side has defeated the other.
Ship Battles Step by Step
Determine surprise: The GM determines whether anyone involved in the combat encounter is surprised.
Establish positions: The GM decides where all the characters and monsters are located. Given the ships’ stated positions in the an area the GM figures out where the adversaries are how far away and in what direction.
Roll initiative: Each ship involved in the combat encounter rolls initiative, determining the order of combatants’ turns.
Take turns: Each participant in the battle takes a turn in initiative order.
Begin the next round: When everyone involved in the combat has had a turn, the round ends. Repeat step 4 until the fighting stops.
Surprise!
An orcish pirate ship glides out of the fog and attacks a dwarven merchant galley. A dragon turtle swims up beneath a knarr, unnoticed by the crew until the dragon turtle blasts the deck with scalding steam. In these situations, one side of the battle gains surprise over the other.
The GM determines who might be surprised. If neither side tries to be stealthy, they automatically notice each other. Otherwise, the GM compares the Dexterity (Stealth) checks of anyone hiding with the passive Wisdom (Perception) score of each creature or crew rating on the opposing side. Any crew or monster that doesn’t notice a threat is surprised at the start of the encounter.
Special: Creatures and characters proficient with water vehicles can instead make Dexterity checks and add their proficiency bonus rather than making Dexterity (Stealth) checks.
If your ship is surprised, it can’t move or take an action on its first turn of the combat, and you can’t take a reaction until that turn ends. A ship’s crew in a flottila can be can be surprised even if the other crews aren’t.
Initiative
Initiative determines the order of turns during ship battle. When a battle commences the pilot of each ship makes a Dexterity check to determine their ship’s place in the initiative order. A pilot proficient with water vehicles can add their proficiency bonus to the Dexterity check to determine initiative order.
Each member of a ship’s crew takes their turn at the same point in the initiative order. This allows each member to coordinate their actions with each other.
Characters on Ships
Roles
Characters on a ship can fulfill one of several rolls which will determine what they can do on board the ship. A character can fill any number of rolls, so long as they can reach all parts of the ship necessary to fulfill that role, or at least be able to shout orders at the crew who assist with that role’s actions.
For example a knarr typically has a navigator, a pilot, and two dozen rowers. A character could be both navigator and pilot, but would find it impossible to steer a ship while also acting as an oarsman. While a larger vessel such as a caravel has a crew of nearly one hundred but still only has one captain, one pilot, one navigator, and so on.
Captain: The captain of a ship is in charge of the overall operation and function of the ship. This role involves the overall command of a vessel as well as determining the overall tactics in combat. Some navies leave all disciplinary action at discretion of the captain, and and often refer to the captain Master-and-Commander. A ship may only have one captain.
Pilot: The pilot of a ship is directly responsible for steering the vessel both in and out of combat. A ship may only have one pilot at a time.
Navigator: The ship’s navigator plots course when not in combat. While in combat the navigator keeps the crew working the sails, oars or other means of propulsion. A ship may only have one navigator at a time.
Gunner: A ship’s gunner is in charge of a crew of two or three sailors that loads, aims, and fires a particular weapon. A ship may have as many gunners as there are weapons on board.
Carpenter/Enginee]r: The carpenter position onboard a vessel is responsible for repairing damage and maintaining the integrity of the ship and her parts. A ship may only have one carpenter or engineer.
[B]Other crew: Other members of the crew offer supporting roles to the ship’s main roles as well as providing support through their own abilities, skills, or spell casting. These roles can involve healing the injured, fighting boarders, or assisting other roles through the use of the help action.
Passenger: Passengers have no formal role on board a ship. However they are capable of stepping and filling any role, provided the crew is willing to let them.
Actions in Combat
Normal Actions
On a ship’s turn either the pilot or navigator can move the ship a distance up to the ship’s speed. Each crew member can also take one action. The navigator or pilot decides whether to move first or have the crew take their actions action first. The ship’s speed is noted with the ship’s statistics. The only limitation on a ship’s movement is that it cannot move immediately back into a space it just left.
The most common actions you can take are described in the “Actions” section. Many class features and other abilities provide additional options for your action.
You can forgo moving, taking an action, or doing anything at all on your ship’s turn. If you can’t decide what to do on your turn, consider taking the Dodge or Ready action.
Bonus Actions
Various class features, spells, and other abilities let you take an additional action on your turn called a bonus action. The Cunning Action feature, for example, allows a rogue to take a bonus action. You can take a bonus action only when a special ability, spell, or other feature of the game states that you can do something as a bonus action. You otherwise don’t have a bonus action to take.
You can take only one bonus action on your turn, so you must choose which bonus action to use when you have more than one available.
You choose when to take a bonus action during your turn, unless the bonus action’s timing is specified, and anything that deprives you of your ability to take actions also prevents you from taking a bonus action.
Reactions
Certain special abilities, spells, and situations allow you to take a special action called a reaction. A reaction is an instant response to a trigger of some kind, which can occur on your turn or on someone else’s. The opportunity attack is the most common type of reaction.
When you take a reaction, you can’t take another one until the start of your next turn. If the reaction interrupts another creature’s turn, that creature can continue its turn right after the reaction.
Breaking Up Your Move
You can break up a ship’s movement on your turn, using some of its speed before and after other actions. For example, if the ship has a speed of 300 feet, it can move 100 feet, characters can take their actions, and then the ship can move another 200 feet.
Using Different Modes of Travel
If your ship has more than one mode of travel, such as sailing and a flying, you can switch back and forth between your modes of travel during your ship’s move. Whenever you switch, subtract the distance you’ve already moved from the new speed. The result determines how much farther you can move. If the result is 0 or less, you can’t use the new speed during the current move.
For example, if you have a sailing speed of 300 and a flying speed of 600 because the ship is also a blimp, the ship could fly 200 feet, then sail 100 feet, and then take off into the air to fly 300 feet more.
Other Activity on Your Turn
There are a number of actions that a character can take their turn. Some of these actions are restricted to characters fulfilling a specific role onboard a ship. The following list is extensive although not exhaustive, if you wish to attempt something not included ask your GM and determine what checks and type of action might be required.
All out Movement: This requires the navigator’s bonus action. As a bonus action after using the Increase Speed action the ship may move up to its normal speed. However, on the following turn its speed is reduced to half of its normal speed.
Attack with a Ranged Weapon: Any crew member that has not otherwise used their action can attempt this action. You can attack an opposing vessel or her crew with your personal weapons as long as the other ship is in range.
Attack with a Ship Weapon: Requires the gunner’s action. You can attack an opposing ship or creature with one of your ship’s weapons.
Weapon Batteries
At battery is a group of up to six of the same weapon. No Help action is required to receive the benefit of the Help action of another gunner. Additionally each point the attack roll exceeds the target’s Armour Class another weapon strikes the target adding a +1 die to the damage. Add this die before adding any other multipliers. Ships armed with weapon batteries have this information in their statistics already, although each weapon can still be fired independently if need be.
Avoid Collision: As a reaction make a DC 15 Dexterity check with proficiency if you are proficient with water vehicles. On a success your ship takes only half damage from a collision or ramming. Only the pilot can take this action.
Cast a Spell: This requires your action. Cast a spell on a target in range. Any crew member capable of casting spells that has not otherwise used their action can use this action.
Defensive Manoeuvres: This requires your action. Upon initiating defensive manoeuvres you focus entirely upon steering the ship to avoid attacks. Until the start of your next turn, any attack roll made against the ship have Disadvantage. Only the pilot can use this action.
Help Action: You can lend your aid to another creature in the completion of a task. When you take the Help action, the creature you aid gains advantage on the next ability check it makes to perform the task you are helping with, provided that it makes the check before the start of your next turn. Any crew member that has not otherwise used their action can attempt this.
Increase Speed: This requires the pilot’s action. If you are proficient with water vehicles you can temporarily push your vessel beyond its normal limits. This can be either by rapidly changing the rigging on a sail, inspiring your rowers to greater feats of strength, or some other manner of producing greater speed. Make an Intelligence check plus your proficiency bonus against DC 15 to increase the speed of the ship by 50% rounded down, or rounded down to the nearest 100 feet if in combat.
Ram: This requires the pilot to take an action. The ship must move at least half of its speed in a straight line towards the target ship or creature and end its movement in the target’s space. A DC 10 Dexterity check is made with disadvantage, if the character making the check is proficient in water vehicles add their proficiency bonus to this check.
On a success the target is rammed and takes damage, and the ramming vehicle takes half of the listed damage rounded down. If the Dexterity check fails the both the target of the ram, and the ramming ship take normal damage. Damage is calculated by taking the non-combat speed of the ship and rolling that many d6s and multiplying the resulting damage by the Size Multiplier on Table X-X: Vessel Sizes. For example a huge ship with a 12kn (600 ft) speed rams a kraken. 12d6 x 4 is rolled for an average result of 168 points of damage. On a successful Dexterity check the ramming ship only takes half of that damage, on a failed Dexterity check both the kraken and the ramming ship receive the full amount of damage. Ships equipped with naval rams have special rules associated with ramming.
Ship Statistics
Attack
The attack statistic of a ship represents the ability of a the crew to operate the weapons and other attacks of the ship.
The basic attack roll of each ship is determined in the following way:
D20 + proficiency bonus + size modifier + other bonuses
Ship Size
The size of a ship indicates how large it is compared to other vessels. Due to how large even the smallest ships are compared to a typical creature ships a broadly classified into three categories: small ships, large ships, and huge ships.
Table X-X: Vessel Sizes
Vessel Size
Size Modifier
Average Length
Examples
Samll Ship
+0
40 to 100 feet
Knarr, caravel, cog
Large Ship
-2
125 to 200 feet
Brig, corvette, frigate
Huge Ship
-4
200 feet or longer
Galleon, Man o’ War
Tonnage
A vessel's tonnage represents how much cargo it can carry in general. Ships can carry this amount an travel at their normal speed. A vessel can carry double this value but it halves its speed as the much heavier load slows the ship.
Armour Class
All ships have an Armour Class. This value indicates how difficult a ship is to hit and damage with other ship based weapons.
The armour class of a ship is calculated as follows:
10 + size modifier + other armour
New weapon trait: Fixed Mount
Weapons with the fix mount trait deal triple damage against ships, objects, and creatures of huge and gargantuan size. Attacks made against creatures of large size and smaller are made with disadvantage on the attack roll.
Weapons
The weapons on a ship are used to engage in combat against other ships. Many ship based weapons have a new property: fixed mount.
All ship weapons have both a normal and long range value. Like creature scale weapons the normal range represents a weapon’s range in feet. Attacks made at long range have disadvantage on the attack roll and represent the weapon’s maximum range in feet.
Hit Points
Just like creatures ships have hit points. Hit points abstract a variety of the factors in ship to ship combat into one number that represents how close a ship is to being disabled.
When a ship reaches 0 hit points is it considered to be disabled. The crew cannot move the ship, nor can they fire the weapons. Although, it is still possible to repair the ship to working order either through magic, on board supplies, or outside assistance.
When a ship is reduced to its hit point maximum below 0 then it is destroyed and will completely sink within ten rounds of combat, or five minutes. Normally a ship in this condition is unable to be repaired, although the DM may allow extraordinary measures to stave off disaster or avert it completely.
Crew
This indicates the number of crew a ship requires to function in combat, as well the roles typically found on such a ship. Most ships have at least double the minimum crew needed to operate a ship in battle. It also indicates how skilled the crew is by presenting a generic proficiency rating for the crew as a whole. See the Crew Skill sidebar for more information.
Crew Cover
Most ships provide half cover to their crews and other creatures on their main decks. Creatures below deck typically have full cover, although some ships may provide only three-quarters cover to creatures below deck depending on the ship’s particular configuration.
Crew Skill
Rather than provide details for each individual member of a crew the following table provides a general overview of how skilled a particular crew is at operating their vessel. It can generally be assumed that the crew of a ship are proficient in the skills necessary to operate that vessel such as Strength (Athletics), Wisdom (Perception), water vehicles, and Wisdom (Survival)
The Default Ability Score is the score for any given skill check that isn’t otherwise listed for the crew.
Crew Skill Level
Skill Bonus
Default Ability Score
Untrained
+0
8
Green
+1
10
Skilled
+2
12
Veteran
+3
12
Expert
+4
14
Master
+5
16
Speed
Every ship has at least one speed rating. This determines how far a ship can move in each round of combat, much like character’s speed indicates how far a creature can move in each round of combat.
The speed of a ship indicates how fast a ship can travel in knots outside of combat. The second number in brackets is the number of number of feet a ship can move under normal circumstances in combat. Some abilities, spells, or manoeuvres may allow the ship to move faster, or slower than this rate. For example an elven caravel has a speed of Sails 13 knots (600 ft), meaning that in combat it travels at a rate of 13 knots (approximately 17 miles per hour) while it can use its sails, and roughly 700 feet per combat round while under sail.
Some ships may have more than one speed depending on how many means of propulsion they possess. No matter how many means of propulsion are used only the highest speed is counted if several are deployed at once. For example, a dwarven galley with speeds of Sail 8 knots (400 ft) and Rowing 11 knots (600 ft) will only use the rowing speed if both the sails and oars are used at the same time.