super-simple naval combat for any edition

bpoatyAs promised, here are my naval combat rules. They’re based on two principles:
1) D&D naval combat should be as D&D as possible, and
b) any rules subsystem should fill a single sheet of paper at most.

My basic rules take up less than half a page and could probably fit on a business card. I’ve filled up the page with optional rules: the nautical complications that Patrick O’Brien buffs will expect, from tacking against the wind to acting as ship’s surgeon.

Download the PDF or read on.


Ships have Armor Class. AC is the same as leather armor for peaceful/clumsy ships and chain mail for warships/maneuverable ships.

Ships have Hit Points. Most ships have 1 HP per minimum crew. Warships typically have 30 HP.

Ships have a speed. 30 feet/round (about 3 mph) is average. Ships have no maneuverability class or facing.

Ships have initiative. Ships have no initiative bonus. All crew and passengers act on the ship’s initiative.

Ships fire ranged weapons. Each round, a ship may fire one weapon per 10 max HP. Ballistae do 1d8 damage and catapults 1d10. Attack rolls are made as a level 1 fighter and have the same range as a shortbow. Every 10 passengers may fire 1 volley of arrows (1d6 ship damage).

Individuals can attack a ship. Divide individual damage by 10, rounding down. Ship weapons do x10 damage to individuals. The DM arbitrates non-damage spells. Ships save as a level 1 fighter.

Ships collide. Boarding follows normal D&D melee rules. A galley with a ram does 2d10 damage and may sail through a destroyed ship or back up from a whole one.

Crew die in battle. The crew takes one casualty for each HP of ship damage (half killed, half unconscious at 1 HP).

SAMPLE SHIPS: HP and speed vary +-50% based on ship quality.
boat: open boat, raft, keelboat. Spd 20. HP 3. AC as leather.
longship: Can land on shore. Spd 35. HP 10. AC as chain.
galley: heavy rowed ship. Spd 30. HP 30. AC as leather.
sailing ship: merchant ship. Spd 30. HP 20. AC as leather.
warship: armed sailing ship. Spd 35. HP 30. AC as chain.
leviathan: Absurdly large ship. Spd 25. HP 50+. AC as chain.
Technologically advanced ship: Stats as previous ship types, but AC as plate mail, d12 weapons, and/or speed +10.

And that’s it for the basic rules! Everything further on this page is optional, to be used by the DM when the players start asking about advanced tactics: can we aim at their sails? Can we fire flaming arrows?


Crit Location: On a critical hit against a ship, the attacker may forego extra damage for one of the following:
1) Sail Damage: The ship’ speed is slowed by 10 until the crew skips a turn for repairs.
2) Called Shot: The attack (non-critically) hits a specific character or object.
3) Weapon Hit: A ship weapon is destroyed.

Fire: If a flaming weapon crits, or an attacker fumbles a flaming weapon, or the ship rolls 1 on a save vs fire, the ship burns. It takes 1d6 damage on the opponent’s turn. On its turn, its crew has a 50% chance to put out the fire.

Wind Direction: Occasionally, strong winds affect navigation. Only rowed ships can go directly into strong wind. For instance, in a strong north wind, you can’t sail north (but you can sail NW and NE).

Officer Actions: This rule is meant to involve multiple players on each turn. On the ship’s initiative, a PC can use his/her turn to take an officer action. If you want important NPC ships to have skilled officers, add +1, +2 or +3 to the ship’s AC, attack rolls, and damage rolls.
Captain: Order broadside: The captain’s player chooses an enemy to attack this turn. Add the captain’s Int or Cha bonus to the ship’s damage rolls against that enemy. (Pre-Third Edition: Int bonus: 1/2 the number of bonus languages. Cha bonus: 1/4 max henchmen.)
Master Gunner: Aim weapons: The Master Gunner’s player rolls the ship’s weapon attacks, adding his or her Dex bonus (pre-3e: reaction bonus) to the attack rolls.
First Officer: Fill in: The first officer may take any officer action that is not being performed this turn.
Helmsman: Con the helm: The helmsman’s player moves the ship. If the ship moves, add the helmsman’s Dex bonus (pre-3e: AC bonus) to the ship’s AC.
Ship Surgeon: Operate: Must have clerical/healing skill. The surgeon’s player tracks damage to the ship. If the ship lost any HP last turn, the surgeon restores 1 ship HP.

Download the PDF

12 Responses to “super-simple naval combat for any edition”

  1. Baron Greystone says:

    Looks great, can’t wait to try this out! I’m a fan of brevity.

  2. 1d30 says:

    Does ballista / catapult damage vs. men line up with giants’ thrown boulders against men? Based on that you might want to reduce the multiplier for ship weapons vs. men.

    I’d also suggest that men can’t damage ships with handheld weapons. Perhaps to compensate give rowboats hitpoints as creatures instead of hull points, meaning a higher number but they take lots of damage.

    Otherwise I don’t see why ships shouldn’t just have say 300 HP instead of 30 hull points.

    One reason why you might want to use 10 men to fire a weapon that only does 3x the damage of 1 man, would be if man-portable weapons can’t damage a ship, and if the range of the ship weapons is quite long and you can get a few shots in before closing to arrow range.

    I’d also make crew casualties as a result of ship damage only occur on perhaps a damage roll of 1 or 2 on d6 (in this case, injuring 1 or 2 men). This way it’s worthwhile to direct the weapons against the men rather than their ship, even if you don’t want to board and seize the ship.

    I’m sure these rules are fine, but I think you could make it a 2-page doc and include maneuverability, facing, a description of what happens when the ship’s HP are gone (does it get a hole and begin to take on water, or does it break up), and some ship modifications like hull plating or extra rigging.

  3. trespassers says:

    I love it! For the first time I want to run a naval battle!

  4. paul paul says:

    1d30: Some interesting points, which I’ll address in reverse order.

    Making a 2-page doc including maneuverability and facing: I’m ok with a 2-page doc (because it can fit on one sheet double-sided), but I specifically want to exclude maneuverability and facing for the same reason they’re often excluded from D&D melee combat. For ease of play, that’s elided under Armor Class. Even though Maneuverability has been in D&D since OD&D, I suggest that it is less D&D in spirit than Fight In The Skies.

    Crew Casualties: I can definitely see the case for separating crew and hull damage – but D&D would be more realistic with a Wounds/Vitality separation too but it plays best without it. I think naval combat plays best with as few damage tracks as possible, especially with 3+ ships.

    Why not have ships have 300 HP? The /10 damage, round down, means that most people cannot harm a ship in any way. You need a magic weapon or a spell to do any damage at all.

    Does damage line up with giants’ thrown boulders? This is an extremely good point/question. Giants do an average of 9 through 25 damage with thrown rocks. This suggests that 10-80 damage for ballistae may be too high. One possible tweak is to use the Basic D&D damage expression instead: personal attacks do 1/5 damage to ships and ships do 5x damage to individuals, instead of my x10. This might be a superior model. I’m sad to do this because, while “divide by 5” is quick math, “divide by 10” is instantaneous non-math. Also, “divide by 5, round down” means a weapon user has a small chance of doing damage to a ship with bow or axe.

  5. John McCollum says:

    Really like the brevity and simple execution of mechanics. Downloaded the PDF for use in my Pirate scenarios!

  6. 1d30 says:

    Those are some good points, and for some reason I was misreading the personal / 10 for hull damage. I think I read it as “30 archers did 30d6 total, divide by 10 and round down” rather than “30 archers each did 1d6, divide each by 10 and round down”.

    You don’t need to meet halfway with personal damage 1/5 vs ships and ship weapons x5 vs people. You could have ship weapons x5 vs. people and multiply hull value numbers by 5. You’re trading undesirably large numbers for retaining “arrows can’t pierce a hull”.

    I believe Spelljammer had a roughly 1d6 = 1 hull point for spells like Lightning Bolt and Fireball, except perhaps Fireball wasn’t as effective against non-wooden ships or something. The DMG 1E has a siege engine table for spells vs. fortifications, and I believe those two spells deal something like 1 or 0.5 siege point per caster level (equivalent to 1 per 3.5 damage or 1 per 7 damage depending). You could say the ship can take X dice of damage before sinking – don’t even roll damage – but all attacks are at -1 die (so a giant with a 2d6 attack would be downgraded to 1d6, or 1 hull point per hit). That cuts out all of the math, but also cuts out some unpredictability. And it deviates from the typical D&D combat rules – although all of these deviate some.

    I personally use d6 damage and HP dice, varying only for extremely large/strong creatures (ogres are d6+2, giants 2d6 to 3d6, sea monsters 2d6 or higher, etc.) or for especially strong magic items (a Vorpal Sword does 2d6, so it can slice through doors for example). This suggestion of counting dice of damage ignores damage bonuses such as from a +5 axe, and ignores damage die size (meaning a 2-handed axe of 1d12 damage still can’t hurt a ship). I think both of those are valuable outcomes in my game, but maybe not in most.

    As for the two damage tracks, that brings up the whole point of ship vs. personal damage – you might want to capture the ship “alive” and steal it, much like you might want to capture a creature alive for interrogation or ransom. Maybe use whatever rule for subdual damage, and if the target would fall unconscious or be subdued that means the crew is blasted and the rigging is down. Synergy with whatever existing combat system and only one damage track.

  7. Paul says:

    Specifying that you can do subdual/nonlethal damage to a ship is a really good idea.

  8. Michael (Gronan) Mornard says:

    You need to play “Don’t Give Up The Ship” by Dave, Mike Carr, and Gary.

    Played it last weekend at Garycon VI for the first time in about 35 years. I’d forgotten how ____ing much fun that game is!

  9. paul paul says:

    I need to even find a copy to read.

    I should try to make it to garycon next year – I still haven’t played chainmail.

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  11. JML says:

    Do you have an updated version of these rules to work with D&D 5e? Maybe something using the Advantage/Disadvantage rules, etc?

  12. ThomasLee says:

    Is this copyrighted? More, could I have permission to use this in my campaign? Preferably, it would be better if this isn’t copyrighted as the administrator wishes resources to be open source used on his site.

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