How many rounds should ship combat last?

[Amnestic]

"Captain, ship sighted!"
The call goes out and all crew members rush to get into position. Raising his spyglass, the captain confirms the sight: A sailing ship bearing the colours of vile slavers. Piracy is one thing - that's just making a dishonest coin - but slavery was something no one on board could abide. The orders followed swiftly.
"We'll sink them to the bottom of the Locker. No mercy!" Cheers met the Captain's declaration. Only the First Mate stayed quiet, standing at the side of the ship's master.
"Pardon, Captain, but with our weaponry and their hull, it will take at an average of fourteen rounds to sink them. Likely more, if we have low rolls for the ballista's damage dice."
"Eh? Fourteen? That can't be right."
"I'm afraid it is. Between disadvantage as we get closer and the hull's damage threshold and high hit points, it'll take likely this entire gameplay session of back and forth just to sink them."
The Captain huffed.
"Well, what if we boarded them instead?"
"Probably half-as-many rounds to take the ship, and then we can just say we sunk it in non-tracked time. Of course, we'd need to make successful boarding checks too, and only two of the Officers have any decent dexterity."
"I knew we should have played that martial arts tournament campaign instead."

I understand that this question is kinda like "how long should a piece of string be" but it's one I'm having a bit of trouble with. I'm looking at revising the Saltmarsh ship combat stuff, initially just to give other players than the Captain something to do during it, but as I'm coming to the end I'm looking at ship health numbers and finding them...possibly 'accurate' but also not 'fun', potentially.

This is being done in preparation for an eventual pirate campaign, and since it's ship combat it's primarily going to focus on Sailing Ships, Warships, and Galleys, since that's what they're most likely to hit upon on the open seas.

Sailing Ships have 300 HP hulls and damage threshold 15. They have one Ballista (+6, 3d10) and one Mangonel (+5, 5d10)
Warships have 500 HP hulls and damage threshold 20. Two ballista, two mangonels.
Galleys are the same as warships, but with an extra two ballista.
All of them have 15 AC.

My little fake example above was me extremely roughly guesstimating a battle between two sailing ships - the ballista deals zero damage half the time it hits, and the Mangonel is better, but still hardly guaranteed. It gets worse between two warships, where the hull gains an extra 200 hit points and 5DT, but only one extra ballista and mangonel. Even if you scrapped the damage threshold for the sailing ship battle, it's 14 rounds of back and forth (~44 damage per turn, missing half the time) when you ignore ranged disadvantage entirely.

What this means is that, realistically, a straight ship battle with the aim of sinking is going to last a long time of back and forth, probably with a fair amount of missing or zero damage dealt. Not super fun! Probably. Especially not if it's done regularly as a central feature of the campaign. It could really start to drag.

This does, in a way, encourage 'realism' in that ships are less likely to be sunk, but instead softened up a bit before you board and take them yourself, which I get, that's kinda neat especially for piracy, but if there's no real danger of sinking either side from the ship combat...should we not just skip it to get to the actual dangerous part? Ideally I'd like to strike a balance.

So I guess my question is twofold, really.
1) For those who have experience directly with these rules having played them, did you find this a drag? Did the above hypothetical duration match your experience? Or was it fine and I'm making a mountain out of a molehill?
2) On the scale of how to adjust, would people generally prefer to see hit points/DT adjusted or damage numbers adjusted? Eg. Is it more fun to have the above damage numbers vs. 150HP, or double the damage so you're rolling 10d10 mangonel stones? Or both? Is seven rounds to sink a ship instead of damaging+boarding it 'appropriate'? It'd mean that if you were going to board, chances are it'd be ~3 rounds of closing+weakening the vessel, then ~3-4 to kill the defenders and make them surrender.

[JackPhoenix]

There's a reason why, historically, boarding and/or ramming was the way to go in naval combat. Sinking ships isn't easy until you have cannons. The 16d10 damage from ramming is much more impressive, though you still 5 ramming attempts to sunk a warship (and your own ram will likely break after two). Or set them on fire. It'll take a while for the entire ship to burn down, but you can just let it run its course.

Also, those fourteen rounds may be a lot in a real world, but it translate to a minute and a half in the game. That's insanely fast. Naval battles often took hours.

[Amnestic]

There's a reason why, historically, boarding and/or ramming was the way to go in naval combat. Sinking ships isn't easy until you have cannons. The 16d10 damage from ramming is much more impressive, though you still 5 ramming attempts to sunk a warship (and your own ram will likely break after two). Or set them on fire. It'll take a while for the entire ship to burn down, but you can just let it run its course.

Cannons are definitely a big upgrade over ballista, though at 8d10 they're not doing that much more over mangonels. A sailing ship with two cannons is sinking a fellow sailor in ~7 rounds instead of ~14, so that's not so bad, all things considered. Maybe? I dunno, again, it's just numbers to me rather than any actual playtest experience.

Also, those fourteen rounds may be a lot in a real world, but it translate to a minute and a half in the game. That's insanely fast. Naval battles often took hours.

Oh aye, I fully recognise that. One of my unrelated changes is changing "ship combat" rounds to 30 seconds instead of 6 seconds with adjusted movement speeds to match. That still only makes the hypothetical 14 round combat into a seven minute engagement rather than hours, but it's a slightly less fast conclusion.

[Khosan]

You might want to take a look at Star Wars 5e's starship rules and use that as a basis for changes. Link to the SRD's section on ships here where you can find all the rules. There's a lot of stuff to dig into there and see what strikes you as interesting and fun.

Quick version is ship's have their own ability scores with a number of hull points roughly comparable to how many hit points a player character has and ship weapons deal hull damage. You can convert between regular hit point damage and hull damage, but it's heavily in favor of using ship weapons for ship stuff:

SPACE VERSUS GROUND
The most important distinction here is the scaling down of the dice. An X-wing’s laser cannon deals 1d6 to an enemy X-wing. The perspective for damage here is space. If you need to scale ships to the perspective of players, you want to scale the damage, hit/hull points, shield points, damage reduction, and shield regeneration rate of ships by 10, and vice versa. For Instance, an X-wing’s primary weapon may deal 1d6 to ships, but would deal (1d6)x10 to a player, while a player’s explosion power would instead deal (8d6)/10 damage (round down) to the X-wing.
Because of their size and durability, some GMs may rule that Large and larger ships are simply immune to damage from small arms fire.
Additionally, a Tiny starship is Tiny on the space scale, but Huge on the ground scale. Consequently, a Small ship is Gargantuan on the ground scale. Medium and larger ships would be considered colossal.
Because starships are not primarily designed to fight individual creatures, Tiny-Large Starships have disadvantage on attacks versus Large and smaller creatures (and such creatures have advantage on saves caused by these ships’ weapons).

I think base 5e is getting bogged down in trying to make sure players feel the effect of that, between the huge health pool and the damage threshold, but hasn't scaled up the ships' weapon damage to compensate.

[Unoriginal]

[I]"Captain, ship sighted!"
The call goes out and all crew members rush to get into position. Raising his spyglass, the captain confirms the sight: A sailing ship bearing the colours of vile slavers. Piracy is one thing - that's just making a dishonest coin - but slavery was something no one on board could abide. The orders followed swiftly.
"We'll sink them to the bottom of the Locker. No mercy!"

"And if any slaves are on this ship, stick them in your prayers I guess, 'cause I already ordered to sink that ship and kill everyone and I for one am not one to make exceptions."

2) On the scale of how to adjust, would people generally prefer to see hit points/DT adjusted or damage numbers adjusted? Eg. Is it more fun to have the above damage numbers vs. 150HP, or double the damage so you're rolling 10d10 mangonel stones? Or both? Is seven rounds to sink a ship instead of damaging+boarding it 'appropriate'? It'd mean that if you were going to board, chances are it'd be ~3 rounds of closing+weakening the vessel, then ~3-4 to kill the defenders and make them surrender.

Could try keeping the DT and damage the same, but give the ships 1/4 of the HPs.

[Sorinth]

Well if the players are doing nothing beyond using the ship to attack then 14 rounds isn't actually going to take that long in real time so each round will go by quickly. If the players are doing stuff then that will cut down on the number of rounds.

But also you don't have to target the Hull, the other ship component's don't have the same HP or damage thresholds. So for example your Ballistas should go after a hull where you'll mostly end up not getting the damage threshold, instead target the ships weapons, helm, or sails which have no damage thresholds.

And of course there's also surrender which probably should happen in most cases long before the hull is reduced to 0 HP. Which incidentally means you killed all the slaves. Take out most of the weapons, damage the sails/oars and surrender should pretty much be guaranteed.

[MarkVIIIMarc]

Combat should last as long as it is interesting.

Feel free to condense ships closong range until soneone on either ship casts fireball or shoots a flaming arrow at the other.

[NichG]

I find ship/vehicular combat systems in general really hard to get right. I'm convinced the issue is largely that combat in general has a lot of time spent on resolution and normally each player could spend that thinking about their own situation and what they're going to do, but when you unify everyone onto a single ship then, even if players are handling different duty stations, that time stretches out much worse than an equivalent amount of time in a combat between individual characters. Sure maybe one guy is in charge of the port cannons and one guy is in charge of the starboard cannons and one guy is charting a course, but like 'I fire at the enemy' doesn't require much thought.

So I guess my ideas would be:

1. Don't treat the conflict between ships like a combat at all. It's a situation where player actions can influence the situation, but focus the resolution on things like 'there's a fire and its spreading towards the ammo', 'the last salvo injured 15 crewmen, they need to be healed or replaced within the next few minutes to do necessary combat maneuvers', 'over the next few hours of this pursuit, do we hide in the fog or seek out a storm or try to find some shoals?'. You'd need an alternate way of basically tallying up the consequences of these individual scenes, and enough of a logic that players can make informed decisions (which might mean broadcasting consequences like 'if you find a storm, both you and the enemy will risk significant damage or even sinking outright based on crew and pilot skills; if you hide in fog, no direct risk but instead you have a chance between losing them entirely or being ambushed'

Ship weapons could be pure environmental effects in this case - if the individual scene involves doing things 'while under fire', there are occasional AoEs dropped on the field, etc that you have to take into consideration. They could have a rhythm to them like 'AoEs drop one round, one round spent reloading' or 'alternating fire hits fore then aft then fore then aft' that would just be part of the field.

2. If you are going to run it as combat, have a setting conceit that gives each PC their own independent craft to control. Easier in a sci-fi game (scramble fighters!) but high level fantasy where everyone has a source of flight could do it too. I'd probably want ship integrity to be such that it would actually take a character a really long time to make a significant go at sinking/breaching the ship on foot. Maybe a ship combat round is a full minute, but ships have sections rather than a total HP score, and you need to destroy a significant number of sections in order to actually scuttle a ship. Like, an individual fightercraft might have 8 sections and could stay intact as long as half haven't been destroyed (but risk losing weapons/engines/whatnot as sections are individually destroyed). A big ship could have hundreds of sections. Ship-based weapons don't just do more damage than individual-level abilities, but they also can hit multiple sections at once; set them to be super-lethal if they actually hit an unprotected individual, but they only fire once a minute and (depending on tech level) might even telegraph where they're going to hit a few rounds in advance. Or they have really easy saving throws if you're fighting at character-scale.

3. Heavily abstract ship weapons and speeds into a 'percentage hitpoint damage applied to each side's characters prior to boarding' and skip right to boarding in every case.

[JackPhoenix]

Cannons are definitely a big upgrade over ballista, though at 8d10 they're not doing that much more over mangonels. A sailing ship with two cannons is sinking a fellow sailor in ~7 rounds instead of ~14, so that's not so bad, all things considered. Maybe? I dunno, again, it's just numbers to me rather than any actual playtest experience.

A ship with two cannons is not designed to sink other ships, but maybe make any opportunist rethink their actions. Try dozen or more... Blackbeard (which is long after the time period with any resemblance to typical D&D setting) had 40.

Oh aye, I fully recognise that. One of my unrelated changes is changing "ship combat" rounds to 30 seconds instead of 6 seconds with adjusted movement speeds to match. That still only makes the hypothetical 14 round combat into a seven minute engagement rather than hours, but it's a slightly less fast conclusion.

I'd suggest a minute. Shooting a torsion-based siege weapon (or even a cannon) every 6 seconds is crazy. A good gunnery crew could make about 3 shots in 5 minutes.

The biggest issue is that there simply isn't any good system (that I know of) for handling a multi-crew vehicle (whether it's a wet navy ship, starship or a tank) on a tabletop. Unless every player gets one of their own, the available posts will never be anywhere near equal.

Well if the players are doing nothing beyond using the ship to attack then 14 rounds isn't actually going to take that long in real time so each round will go by quickly. If the players are doing stuff then that will cut down on the number of rounds.

But also you don't have to target the Hull, the other ship component's don't have the same HP or damage thresholds. So for example your Ballistas should go after a hull where you'll mostly end up not getting the damage threshold, instead target the ships weapons, helm, or sails which have no damage thresholds.

And of course there's also surrender which probably should happen in most cases long before the hull is reduced to 0 HP. Which incidentally means you killed all the slaves. Take out most of the weapons, damage the sails/oars and surrender should pretty much be guaranteed.

True. Simply destroying the opponent's propulsion means you've won. They are a sitting duck now, and even if they still have weapons, they will fixed arcs of fire, and you can just position yourself in their dead angle and sink them at your leisure. In WW2, it took about 2 hours of continual artillery bombardments to sink Bismarck, even though the battle was basically over the moment its rudder was destroyed by aircraft-dropped torpedo and it was immobilized.

[Amnestic]

1. Don't treat the conflict between ships like a combat at all. It's a situation where player actions can influence the situation, but focus the resolution on things like 'there's a fire and its spreading towards the ammo', 'the last salvo injured 15 crewmen, they need to be healed or replaced within the next few minutes to do necessary combat maneuvers', 'over the next few hours of this pursuit, do we hide in the fog or seek out a storm or try to find some shoals?'. You'd need an alternate way of basically tallying up the consequences of these individual scenes, and enough of a logic that players can make informed decisions (which might mean broadcasting consequences like 'if you find a storm, both you and the enemy will risk significant damage or even sinking outright based on crew and pilot skills; if you hide in fog, no direct risk but instead you have a chance between losing them entirely or being ambushed'

I've definitely considered extrapolating it into a series of skill challenges - the main thing that held me off from doing so was the worry that it'd all seem very DM arbitrary rather than something the players could plan for and contribute to beyond rolling whatever dice crop up.

A ship with two cannons is not designed to sink other ships, but maybe make any opportunist rethink their actions. Try dozen or more... Blackbeard (which is long after the time period with any resemblance to typical D&D setting) had 40.

Perhaps the simple answer for me is to just drop more weapons onto ships then as standard. As a bonus, I guess, it'd give the party more dice to roll to spread around.

The biggest issue is that there simply isn't any good system (that I know of) for handling a multi-crew vehicle (whether it's a wet navy ship, starship or a tank) on a tabletop. Unless every player gets one of their own, the available posts will never be anywhere near equal.

I may as well post it since it's mostly feature complete.

Expanded Ship Combat
Currently missing the purchasable upgrades section at the end, plus any adjustments to ship stats I end up making based off of thoughts here/in my own head.

The short version is that there's two phases to each ship turn - the Officer phase, where players can do different skill-based actions based on their role to improve the ship/heal crew/buff weapons, etc. - and the Ship phase, where ships do the whole sailing and shooting thing. While one person will end up rolling the dice, ship actions will generally be decided on by the party as a whole, rather than just the Captain.

Mileage may vary but generally I think they're mostly equal to each other.

[Damon_Tor]

I've always assumed that the bulk of damage dealt to ships in D&D naval combat would come from spellcasters.

[Deepbluediver]

When you say "14 rounds", then yes it does sound like a lot compared to the typical small-group style gameplay where a combat encounter is usually 4-6 rounds, but what actually is going on during those rounds?

Is every party member acting individually? What about other sailors on the ships? Or what about the enemy or other NPCs taking actions? And what kinds of choices are there, exactly, to make. If all your party can do is fire siege weaponry, then even 3 rounds is going to feel pretty boring. Can the party attack the enemy ship (either with spells) or crew (ranged attacks) directly? And how might this help in the combat?
Even if you just lined up a lot more siege-weapons on the deck, as the number of rolls increase your overall values get closer and closer to the average, so it becomes less a contest of interesting tactics, luck, and resource usage, and more just about math-values.

I feel like your question is saying something like "a large-scale battle between 2 armies takes to many rounds". To which the answer is "yes, because the system isn't designed for that". I would suggest not trying to run ship-to-ship combat directly with D&D style rules, and instead go back to the drawing board and try to figure out a way to make it more interesting or more like a typical encounter, or just have your party do something else entirely while the ship-to-ship stuff is background.
Like maybe a Kraken attacks and the party has to fend off THAT while the ongoing ballista attacks are kind of background hazards.

[Kane0]

Oh, I hacked together some naval combat rules for a seafaring campaign some time ago. Feel free to copy anything you like

Spoiler: Rules

Show

Ships have AC, three pools of HP, a top speed, a handling score and suites of directional weapons.

Hull HP measures the structural integrity of a ship. Run out and you start to sink (death saves)
Rigging HP measures the sails, masts, oars, etc. Run out and you are immobilized (can't move or take the Evade action)
Crew HP measures the manpower required for the ship to function. Run out and you suffer disadvantage on all your ship-based rolls.

Size of vessel determined how many dice you roll for Crew HP, and the quality of that crew determines the size of the dice. For example a small sloop with a veteran crew has 3d10 Crew HP, where a galleon that is filled with raw recruits would roll 12d4. The quality of the crew also determines the bonuses of any attacks, checks and saves the ship makes (generally +2 up to +10)

Combat structure

Roll initiative, with ships taking turns like characters. This is best done when only ships are taking turns, or things like ships because their turn is more like a minute than 6 seconds.

Movement is best done on a hex grid, where the handling of a ship is best represented. For example a maneuverable vessel might be able to turn 1 face for every space it moves forward, where a more hulking craft might only be able to turn 1 per 3 spaces moved. You can treat a hex as about 25' big.

A ship has three actions it can choose from: Attack, Evade or Board.
Attack: Make attacks with one direction's worth of weapons
Board: Attempt an opposed check against another adjacent ship, locking them together. Each turn you spend this action to attempt another check, with three successes before three failures claiming the opposing vessel.
Evade: Gain a bonus +2 movement and enemy ranged attacks against you are made at disadvantage until the start of your next turn

On each ship turn a notable character (like a PC) can take a turn (keep in mind one ship turn is a minute, if you're going to cast a duration spell or something). It's largely up to the DM how this turn may affect the ship if you're trying to do things like make repairs, bolster the crew, adjust the winds, etc. It's entirely possible for three characters to spend their actions in order to reload, aim and fire an additional cannon on that turn.

[NichG]

I've definitely considered extrapolating it into a series of skill challenges - the main thing that held me off from doing so was the worry that it'd all seem very DM arbitrary rather than something the players could plan for and contribute to beyond rolling whatever dice crop up.

Not exactly skill challenges, but just a scenario with decisions that have consequences, which may or may not involve skill rolls at all. E.g. it could be more about choosing the risks that even when things go poorly, it hurts you less than it hurts your enemy. I'd want some kind of way of telegraphing the consequences of those choices to the players, as well as suggesting things which could change consequences or odds.

Like, you could make a subsystem for it in advance, but I'd imagine running it to be more of a conversation/planning session kind of dynamic at the table.

GM: "There's a vessel ahead, you identify it as a fast slaver attack ship."
Player: "Could we cripple or sink it before it gets away if we just rushed it and opened fire?"
GM: "Well you've got a significant weapon advantage. Each full salvo you can fire at it would give you a 50% chance of crippling it and a 15% chance of sinking it outright, and failing that you can expect to do damage that increases both of those odds by 15% on successive salvos. The problem is, its faster than you - you're not going to be able to catch up and fire salvos in a contest of speed. If you can get close or get them to close with you, you might be able to get a surprise salvo on them; or if you have some way to hide your approach, but you'll have to figure that out. Also, they're configured for tacking while you're configured for running - if you can maneuver them so you have a strong tailwind, you can negate some of their speed advantage - even then though its probably a coin flip. Because they're a smaller ship, they're going to have a harder time with severe weather than you - if you got them in a storm or extreme waves, you could use that to close."
Player: "Can we have our casters summon a fog and use that to approach?"
GM: "There's a risk that the fog comes off as obviously unnatural to them, especially if they have a caster on board who might recognize the spell. You don't know the odds, but if your gambit pays off that would get you close and get you a salvo."
Player: "What if we have the fighter swim over and sabotage their rudder?"
GM: "That's a DC 10 skill check for the fighter to deal with the waves and open ocean conditions while staying underwater enough of the time to not be spotted. You'll also need some kind of solution to damaging the rudder - you don't have much leverage for weapon swinging if you're doing this while swimming, but pitch or something to tangle the rudder in could do the trick, or if you have some other way of destroying or damaging it. The risk here is that they spot the fighter and start to fire arrows, spells, or ship weapons at him - want to give it a shot?"
Player: "How about if we tail them at a distance, then try to spook them into a storm?"
GM: "Someone give me a DC 10 Survival check to read the weather. Okay, yeah, there's signs of a storm - probably around 150 miles to the southwest and moving eastwards. You'd need to get them to run at the right time. If they think you're hunting them, they might get nervous and run on their own terms - you're going to need to control that somehow."
Player: "Alright, lets go with that idea. Can we stay just beyond the horizon and extrapolate their course, then aim to become visible and have a direct course towards them and the storm at the right time?"
GM: "Sounds reasonable, let me just check to see if they've spotted you or have any of their own plans... okay, I have in mind what they know and what they intend to do, lets run it."

[da newt]

As others have said, large ship combat (like large scale army combat / sieges) is not well suited to D&D which is designed around small squad combat. It's hard to make things realistic-ish, and keep all the Players involved and engaged enough for it to be enjoyable.

My best advice is to scrap vessel to vessel combat entirely, and only play out the crew to crew combat (boarding or at range). It's an unsatisfying answer, but the best one for actual game play I've come across.

[Slipjig]

The ballista in particular just seems like it should be basically useless in terms of sinking an enemy ship. I'm pretty sure I could spend all day firing crossbow bolts at a rowboat, and it's not likely to suffer serious structural damage, let alone sink.

A ballista could certainly kill enemy crew or damage smaller components like a rudder. It might even punch a hole through the hull. But unless that hole is below the waterline, it's not really relevant to the ship continuing to float.

[Sigreid]

The last ship to ship combat we had lasted until the Cleric realized her Tidlewave spell could sweep the deck pretty quickly.

[Doug Lampert]

The ballista in particular just seems like it should be basically useless in terms of sinking an enemy ship. I'm pretty sure I could spend all day firing crossbow bolts at a rowboat, and it's not likely to suffer serious structural damage, let alone sink.

A ballista could certainly kill enemy crew or damage smaller components like a rudder. It might even punch a hole through the hull. But unless that hole is below the waterline, it's not really relevant to the ship continuing to float.

True:
A ballista to the rowers on a galley could potentially be devastating, one man out means his oar fouls a lot of other rowers. But you're not sinking anyone, because the ballista bolt basically stops if it hits water, so you're not putting holes noticably below the waterline.

It's rams, greek fire, or boarding actions to settle a naval action. Even with early cannon, ships simply rarely went down in combat.

Which is ALL GOOD! D&D is best at small unit skirmishing combat, like, say, a boarding action. It's worst at big unit battles where people fight as a cooperating unit, like a naval battle once broadside cannon armament made sinkings a plausible thing to try for.

And boarding being the decisive arm means that you have something to loot after the battle.

I'll note that right up till ironclads and steam came in, boarding was still the most popular way to actually settle a naval engagement, because wooden ships are HARD to sink, most ships were taken rather than sunk even in significant naval victories up to the middle of the 19th century).

[Xihirli]

Hmm.
I would probably break it into two or three "phases" of battle, broken up by skill challenges. This might better show a longer, drawn-out combat. Like first a long-distance round where ranged stuff happens. Then one ship or the other takes evasive action and your need to make skill checks to close or create distance. Assuming distance is closed, move onto a boarding phase with close-quarters combat.

[JonBeowulf]

For stuff like this, I run three complete combats by myself, record the results, and use them as necessary during the game -- as long as the players aren't directly involved. Heck, even if they are I can just narrate everything around them based on what I've already rolled.

I seriously doubt your players will be disappointed that they don't get to sit there while you exercise the game mechanics in real time.