Ship-to-Ship combat

[Yakk]

Ships can support a certain number of Officers. PCs make excellent officers, because you add your level to a number of checks (!).

Ship ranges are as follows:

Contact
Along side
Bow-shot
Cannon-shot
Horizon


Contact means rammed or grappled.

Clumps of ships can be along side each other, and be bow/cannon from other clumps of ships. If a group of ships tries to stay together, it uses the worst maneuver check of the group.

Basic ship stats are:
Crew: (# of squads)/(size of squad)
Crews have a proficiency bonus (+2 to +6).

Warships are often over-crewed; more squads than they need. This makes up for lost crew and helps with boarding.

Hull: HP per Station
Officers: # of officers
Stations: A table of stations. Bigger ships have more stations. Also used as random to-hit table; so 4, 6, 8, 10 or 12 stations.

Stations have actions.

When you resolve a Station, the first thing that happens is an Officer check. They make an attribute check based on what they are doing (with advantage/disadvantage depending on DM's decision) with a bonus equal to the officers level or CR (ie, a level 20 officer has a +20 bonus on top of everything else). Divide the check by 5 and round down; every 5 points they grant the Squad of Crew there a +1 bonus.

However, if your Command check bonus doesn't match the Crew's proficiency bonus, you get in the way; the Squad's station check is at disadvantage.

The entire Crew has a proficiency bonus (+2 to +6). When a station makes a check (cannons attack, etc), it uses the Crew proficiency bonus.

If a Squad is under 1/2, their proficiency bonus is halved. If a Squad is under 1/4 of a squad, they are ineffective and the station is uncrewed.

If a Station is under 1/2, all checks are at disadvantage. If a Station is destroyed, it cannot function.

On some ships officers can do more than one thing at a station. They can only do one of them per turn.

Turn phases:
Command: The captain makes an officer check (attribute check, appropriate skill, +1 per level of the captain): every 10 points on the check get to give 1 order. In addition, 1/turn they can expend their reaction to give an immediate order so long as the Command Station is fully crewed with a squad.

Any station or officer following such an order gets advantage. The immediate order allows both a reroll and advantage.

The commander has disadvantage on this check to give orders if they don't have a First Officer.

Crew: Crew and Officers attempt to change jobs or replace wounded crew; if they make a DC 20 check, they avoid spending their turn in transit, rending the station they are moving to unmanned for the turn.

Repair: A station can choose to repair rather than function. If the ship has a Damage Control station, it can also repair a different station. Make a check; the station gets (check/10)d4 temporary HP, but no more than its current damage. These temporary HP count to get it over the 1/2 way point to prevent disadvantage.

Maneuver: Opposed checks between competing ships. Winner gets to change range by up to 1 unit, and can grant a reroll to 1 check this turn (either of this ship, or enemy attacks on the ship).

If you win the check and don't change range, you can instead switch to broadside. Being broadside gives disadvantage on your future maneuver checks, but means more cannons can be in play.

Whichever ship has the wind-gage gets advantage on their check.

Fire!: Each Cannon Station pointing in the correct direction fires. (aft if you are fleeing, fore if you are closing, a broadside if you have maneuvered so your broadside is pointing at the foe).

DC is 20 at Cannon-shot, 15 at Bow-shot and 10 at Along-side. Cannons cannot fire if you are in Contact.

Roll to hit a random station on the enemy ship. If the station is on the wrong side of the enemy ship, reroll location once.

Damage is applied to the Squad at that Station as well as Hull. Some weapons do more Crew or Hull damage.

Any Officer at the station must make a dexterity saving throw against the attack roll. On success, they take the full Cannon Damage. On failure, they take 5x that damage; that will kill most non-heroic officers.

Sinking!:
The Bilge is a station that cannot (usually) be attacked directly. (unless ramming)

At the end of each turn, if any Station is damaged (half HP) or destroyed (0 HP), the ship must make a Bilge check using the crew's proficiency bonus. The DC is 10 plus the number of Damaged and twice the number of Destroyed stations.

If it fails the Bilge station takes 1d4 damage on the first failure, 1d6 on the next, etc (until it takes 1d20 damage per failure). If your Bilge is reduced to 0 HP, the ship sinks.

If you succeed 3 times in a row without taking further damage, you stop sinking on a per-turn basis and don't have to make further checks. If you do make further checks, each success reduces the Bilge die by 1 step (down to 1d4), but failure starts the sinking process again.

----

Bow-shot:
While at Bow-shot or closer range, Squads can be assigned to fire on the enemy ship. Make an attack roll using their proficiency bonus against AC 10+Enemy Proficiency*2; the Squad at that station and any officers takes 1d8 damage if hit. (reroll below-deck stations; they can't be hit with ranged weapon fire).

Officers can also fire at Bow-shot range if they aren't busy commanding, or if the Squad they are commanding is doing bow-shot. Roll a random station (reroll below-decks stations). They can either hit crew (AC 15, killing 1 crew per hit) or attack an officer at the station (dealing damage to the officer). If they want to pick a specific target, roll the attack at disadvantage.

Short-range weapons (hand crossbows, thrown weapons, etc) can only be used at Alongside range or closer.

An officer can use their turn to cast a spell in order to kill crew or damage the ship if appropriate. They'll generally do 1d6 damage for Cantrips, +1d6 damage per level of the spell expended, at ship-scales (assuming they are effective); spells that are specialized to damage only crew or hull deal d8s instead. The defender can make a saving throw (using the crew's proficiency bonus). Spells targeting officers use standard mechanics; area effect spells on a crew at a station will also hit the officer.

This occurs during the Fire! phase.

Ramming and Boarding:
If you win Maneuver at Alongside range, you can choose to Ram (if ram-equipped) or Grapple and become in Contact.

While in Contact, Cannons cannot be fired.

Ships Ram has a damage rating; attack a station as if it was a cannon shot, but during the Maneuver. The damage is also applied directly to the Bilge.

Once in Contact with the enemy ship, boarding can occur during the Fire! phase.

Each Squad attempting boarding (or retreating) must make a DC 20 check to cross to the other ship. (On a 10 or under, 1d10 crew die from a failed crossing). Then roll a random station (as if it was a cannon attack) to find out where they are attacking.

At an unmanned station, they can deal 1d12 hull damage until it is destroyed, or move to a station of their choice.

If there are defending squads, both sides deal 1d12 crew damage to the other. If one side is has twice the crew at the station of the other, they roll twice and take the better result. If one side has higher proficiency it takes half damage.

Squads repelling boarders move to stations and only act to defend the crew there. When a station is under attack or has extra squads ready to repel boarders, its checks are at disadvantage.

Commanders of squads can grant their bonus to the crew damage (the d12s) instead of the usual d20s. In addition, they can use attacks to kill enemy crew (because fun). AC is (10+2*Proficiency). Each hit kills a single crew (don't bother with damage). They can instead attempt to attack an officer; use usual game mechanics in that case.

...

Sample ships:

Doomsday - 4 master warship
Crew: 20/20 (400) (note: warship, overcrewed by 7.) +3 proficiency
Officers: 8 (undermanned by 3)
Hull Points: 40 per station (520 total)
Stations:
1-4 Masts x4 (+4 maneuver each if crewed)
5-6 Port cannons x2 (2d12 damage)
7-8 Starboard cannons x2 (2d12 damage)
9 Fore cannons (2d12 damage)
10 Aft cannons (2d12 damage)
11 Damage control
12 Command Deck (Command and Maneuver)
Bilge
Ram: 4d12
Broadside Damage: 4d12

Bloody Raven - Fast 2 Master ship
Officers: 5 (undermanned by 2)
Crew: 5/10 (50) +4 proficiency (undermanned by 2)
Hull Points: 20 per station (140 total)
Stations:
1-2: Masts x2 (+6 maneuver each if crewed)
3: Port cannons (1d8 damage)
4: Starboard cannons (1d8 damage)
5: Fore Turret cannon (1d6 damage; 2x damage against crew) (cannot fire aft)
6: Command deck
Bilge
Ram: 2d12
Broadside Damage: 1d8+1d6C

Dung Beatle - 2 Master merchant ship
Officers: 2 (undermanned by 3)
Crew: 3/12 (36) +2 proficiency (undermanned by 2)
Hull Points: 20 per station (100 total)
Stations:
1-2: Masts x2 (+4 maneuver each if crewed)
3: Turret cannon (1d6)
4: Command Deck
Bilge
Broadside Damage: 1d6

Thunder Phoenix - Enchanted 3 master "hero" ship
Officers: 8 (fully staffed)
Crew: 10/5 (50) +5 proficiency (overcrewed by 1; magic makes the ship easier to control)
Special: Warded: The crew has a 50% chance of being protected from any attack or other off-ship hostile effect. Crew also take 1/2 damage from all such effects and attacks and have advantage on saving throws against such effects.
Hull Points: 30 per station (270 total)
Stations:
1-3: Masts x3 (+7 maneuver each if crewed)
4: Port cannons (2d12 damage)
5: Starboard cannons (2d12 damage)
6: Turret (2d10 damage) (special: can pick between 2x damage against crew, or 2x damage against hull)
7: Damage Control
8: Command deck
Bilge
Ram: 3d12
Broadside Damage: 2d12+2d10[C|H]

---

The goal is, as much as possible, to have everything tell a story. So damage applies to stations, not to generic hull points. Crew die and get depleted. Ships parts stop functioning.

It is way way way too detailed for fleet to fleet combat.

PCs as officers are effective, as I made level important. They also make the decision of what their station does. Direct PC action is allowed, especially against officers.

I might have made it too fiddly still. Probably need:

Simplified Officer:
PROF*10 HP
10+PROF AC
+PROF command (no check)
+PROF saves
1d8+PROF damage (melee)
(PROF/2) rounded up attacks
+PROF attack modifier

PROF 2 officer is 20 HP/12 AC/+2 command/+2 saves/+2@1d8+2 damage/1 attack
PROF 3 officer is 30 HP/13 AC/+3 command/+3 saves/+3@1d8+3 damage/2 attacks
PROF 4 officer is 40 HP/14 AC/+4 command/+4 saves/+4@1d8+4 damage/2 attacks
PROF 5 officer is 50 HP/15 AC/+5 command/+5 saves/+5@1d8+5 damage/3 attacks
PROF 6 officer is 60 HP/16 AC/+6 command/+6 saves/+6@1d8+6 damage/3 attacks

This means a simplified officer assigned to a station doubles the proficiency bonus of the crew there.

...

A level 20 barbarian with 24 strength using athletics to help aim and reload the cannons has a +33 modifier to their command check, average 43, so averages +8.5 command. So a +6 prof "generic officer" is not as good as a L 20 barbarian. That is what I was aiming for.

A dX ship with Y masts needs X+1 crew squads and X-Y+3 officers to be fully manned.

Command Decks have the Pilot (maneuver) officer, the Captain and the First Mate officer positions.
Masts don't have an officer position (nor do they make checks), as that is folded into the Maneuver check.