Naval battles

Bannerlord v1.5.7 · checked 2026-11-12 · updated 2026-11-13

Every skill, perk, figurehead, feat, policy and fixed term that changes ship siege weapons, ship morale events, ship damage, simulated ship combat, naval battle rewards, ship costs, ship deployment, ship movement and ship collisions in naval missions in game v1.5.7. All of it is NavalDLC.

Module overrides:

• NavalMissionSiegeEngineCalculationModel (NavalDLC) extends CalculateReloadSpeed and CalculateDamage of DefaultSiegeEngineCalculationModel (the base result first, then naval terms) and replaces CalculateShipSiegeWeaponAmmoCount.
• NavalBattleMoraleModel extends CalculateMoraleOnRamming, CalculateMoraleChangeOnShipSunk and GetEffectiveInitialMorale of SandboxBattleMoraleModel (SandBox).
• NavalDLCCampaignShipDamageModel replaces DefaultCampaignShipDamageModel::GetShipDamage.
• NavalDLCCombatSimulationModel replaces the ship overload of SimulateHit and extends the troop overload.
• NavalDLCBattleRewardModel extends GetCaptureMemberChancesForWinnerParties and replaces DistributeDefeatedPartyShipsAmongWinners, in both the sandbox and the StoryMode campaign (StoryMode's own DistributeDefeatedPartyShipsAmongWinners is replaced too).
• NavalDLCShipCostModel replaces GetShipRepairCost and GetShipUpgradePieceCost of DefaultShipCostModel.
• NavalDLCCombatXpModel extends GetXpFromHit.
• NavalMissionShipParametersModel (campaign) and NavalCustomBattleMissionShipParametersModel (custom battles), and NavalDLCShipDeploymentModel, are NavalDLC models; no other module overrides them.
• ShipCollisionOutcomeLogic is a NavalDLC mission logic, not a model.

Land and agent counterparts: Battles (initial morale, morale loss on a kill, per-hit XP, loot, simulated troop hits), Combat agent stats (agent reload speed, naval agent penalties, the other figureheads), Combat damage (melee damage on ships, sail fire damage), Sieges (siege bombardment).

Skill guides with these perks: Boatswain, Shipmaster, Mariner, Crossbow.

Verdicts: works = does what the tooltip says, or more — broader effects are noted; differs = narrower, different or extra conditions/values than the tooltip; unused = never read by the game; ui_only = only shown in the interface. "Captain" halves come from a formation captain; "FirstMate" halves from the party's First Mate role holder; "PartyLeader" halves from the party's leader hero; "ArmyCommander" halves from the army leader.

Ship siege weapons

Reload speed

ship_siege_engine_reload_speed: the reload speed of a siege weapon operated on a ship. Consumer NavalMissionSiegeEngineCalculationModel::CalculateReloadSpeed (NavalDLC, extends). Base base_reload_speed, explained number, no clamp. This is a different number from the agent's own reload speed.

ship_siege_engine_reload_speed = base_reload_speed · (1 + Σ factors)

• base_reload_speed: the base model's result. DefaultSiegeEngineCalculationModel returns its reload speed argument unchanged.
• Terms apply only while the mission is a naval battle.
• The captain is the operator's formation captain, nulled when the captain is the operator itself.

• Streamlined Operations: its tooltip reads "+10% ballista reload time"; the factor raises the reload speed.
• Viper: its text says ballista reload speed, but it applies to any siege weapon the operator reloads while standing on that ship.

Worked example.

A troop reloads a ballista on a ship with a Viper figurehead in a naval battle. The operator's formation captain (another hero) has Streamlined Operations. Base reload speed from the base model is 1. Inputs: base reload speed 1.

With these inputs, siege weapon reload speed in naval battles is 1.3500.

Streamlined Operations adds its +10% factor next to the Viper figurehead, so the result is 1.3500.

Hull damage

ship_siege_engine_hull_damage: damage a ship siege weapon missile deals to a ship hull. Consumer NavalMissionSiegeEngineCalculationModel::CalculateDamage (NavalDLC, extends). Base floor(base_damage), custom, clamp 0 to 2000.

ship_siege_engine_hull_damage = clamp(ceil(floor(base_damage) · (1 + Σ factors)), 0, 2000)

• base_damage: the damage argument; the base model truncates it to an integer (a floor for non-negative damage).
• No naval-battle test in the method; its only caller is the ship hit handler, and only for missiles from a ship siege engine.

• Shipwright's Insight: only hero shooters are tested.

Starting ammo

ship_siege_weapon_ammo: a ship siege weapon's starting ammo. Consumer NavalMissionSiegeEngineCalculationModel::CalculateShipSiegeWeaponAmmoCount (NavalDLC, replaces the base). Base ammo_count, custom, no clamp.

ship_siege_weapon_ammo = ceil(ammo_count + Σ adds)

• ammo_count: the ammo amount defined on the weapon.
• Called when the ship's siege weapons get their initial ammo after deployment.

Morale events on ships

Ramming

ramming_morale_change: the morale change of the ramming ship's team when it rams an enemy ship. Consumer NavalBattleMoraleModel::CalculateMoraleOnRamming (NavalDLC, extends). Base agent_morale, explained number, no clamp.

ramming_morale_change = agent_morale · (1 + Σ factors)
morale after the ram  = agent_morale + ramming_morale_change = agent_morale · (2 + Σ factors)

• agent_morale: the agent's current morale (−1 for an agent without the AI morale component). The SandBox base model returns it unchanged.
• When two ships of enemy teams collide, the change is computed for every AI-controlled active agent of the first ship's whole team (not only that ship's crew) and added to its morale. The morale setter's own limits then apply.
• The captain is the agent's formation captain, nulled when it is the agent's own character.

• Even with no factor, a ram doubles the morale of the ramming side's AI agents, because the full morale value is added.

Worked example.

An AI troop with morale 50 is on the team of the ramming ship. Its formation captain (another hero) has Shock and Awe, and the ramming ship has a Ram figurehead. Inputs: agent morale 50.

With these inputs, morale change of the ramming ship's team on a ram is 75.0000.

The 75.0000 is added to the agent's current morale of 50.

Ship sunk

morale_change_on_ship_sunk: the morale change of a sunk ship's team. Consumer NavalBattleMoraleModel::CalculateMoraleChangeOnShipSunk (NavalDLC, extends). Base 0, sequential, no clamp.

morale_change_on_ship_sunk = 0 + Enemy of the Wood bonus

• The base model returns 0. The value is added to the morale of every AI-controlled active agent of the sunk ship's team.

• The enemy army leader is the army leader of the first active agent's party of the first team hostile to the sunk ship's formation, read with a fixed naval environment. In mixed teams another army's leader can be checked.

Naval terms on battle morale

The formulas are on Battles and Battles: morale change when an agent falls.

• Lion figurehead: every ship carrying the agent with a Lion figurehead adds 10, for any agent (no party or character test). The agent's own party flagship is skipped when Commodore already applied its figurehead.
• Auxiliaries to the Fleet: the agent needs a party leader hero other than itself. The naval terms join the SandBox sums, so the factor also scales the SandBox adds and the Lion add. It is not gated on a naval battle, so it also applies in land battles (broader than the policy text, naval combat morale of lord parties +20%).
• Terror of the Seas differs: the captain lookup applies the half whose role is Captain, so the secondary half (−10%) lowers the victim side's loss; the +20% primary is never read. The killer's formation captain is checked (including the killer itself).

Ship damage

Campaign ship damage

ship_damage_received: damage dealt to a ship on the campaign side. Consumer NavalDLCCampaignShipDamageModel::GetShipDamage (NavalDLC, replaces the default). Base raw_damage, explained number, clamp min 0.

ship_damage_received = max(0, raw_damage · (1 + Σ factors))

• raw_damage: the damage argument.

• The Ram figurehead factor is read on the attacker ship and raises the damage the other ship takes.

Worked example.

A ship takes 100 raw damage from an attacker ship with a Ram figurehead. The damaged ship's party First Mate has Boatswain 100. Inputs: raw damage 100.

With these inputs, campaign damage dealt to a ship is 95.0000.

Simulated ship-weapon hits

The ship overload of NavalDLCCombatSimulationModel::SimulateHit (NavalDLC, replaces the default) returns two numbers for one simulated ship-weapon hit. The troop overload is on Battles.

ship_simulation_damage: hull damage. Base engine_damage (ranged engine) or engine_damage · hull_size_factor (non-ranged engine), explained number, no clamp.

ship_simulation_damage = engine_damage                                     ranged engine
                       | (engine_damage · hull_size_factor) · (1 + Σ factors)  non-ranged engine (crew strike)

• engine_damage: the siege engine type's damage value.
• hull_size_factor: the striker ship's hull type 0 / 1 / 2 gives 1 / 2 / 3; other types keep 1. Ranged engines use 1.

• Ranged engines skip every term.

Worked example.

In a simulated naval battle a ship with hull size factor 3 sends its crew to strike with a non-ranged engine of damage 10. The struck party's leader has Seaborne Fortress. Inputs: engine damage 10, hull size factor 3.

With these inputs, hull damage of one simulated ship-weapon hit is 27.0000.

ship_simulation_casualties: crew casualties of the same hit. Base ranged_engine, sequential, no clamp.

ship_simulation_casualties = ranged_engine + (1 if Terror holder wins its roll)

• ranged_engine: 1 when the siege engine is ranged, else 0.

• Terror differs: its tooltip speaks of siege bombardment casualties, but this site applies it to ship-weapon hits in simulated naval combat. The perk check takes the striker party's environment, so the land-only half gives nothing while that party is at sea; the ships of a party that joined the naval battle while not at sea still get it. The roll is seeded by the map event's update count; below 0.2 gives +1 casualty. The land site is Sieges: collateral casualties.

Weighted ship combat factor: in naval map events the troop overload of SimulateHit also adds the striker side's weighted ship combat factor as a factor on simulation_damage (works; see Battles).

Combat XP in naval map events

troop_hit_xp: the formula is on Battles. NavalDLC adds its factors on the same explained number after the base model.

• The +0.5 and Naval Fighting Training are two branches of one test: a non-hero attacker gets +0.5; a hero attacker gets Naval Fighting Training only if it is a companion. Non-companion heroes get neither.
• Naval Fighting Training differs: per-hit combat XP, not "after each naval battle".
• Auxiliaries to the Fleet: any map event, land or naval, hero attackers included. Policy text: troop XP gain −15%.

Battle rewards

Prisoner capture share

prisoner_capture_share: each winner party's chance weight to capture defeated members. Consumer NavalDLCBattleRewardModel::GetCaptureMemberChancesForWinnerParties (NavalDLC, extends the default). Base contribution / total_contribution · capture_factor, custom, no clamp. The method fills two lists per winner party.

share_i  = contribution_i · trait_i / total_contribution
w_i      = share_i · 1.0 · (1 + Σ factors_i)
list 1_i = w_i / Σ w                                              (when Σ w > 0)
h_i      = share_i · capture_factor · (1 + Σ factors_i)
list 2_i = h_i / Σ h                                              (when Σ h > 0)

• contribution_i: the winner party's contribution to the battle. total_contribution: the sum over eligible winners. Eligible: contribution above 0, has members, not a villager, caravan or patrol party, nor a garrison or militia in a village.
• trait_i: 1 plus the party leader's merciful/cruel prisoner-capture trait effects.
• capture_factor: 0.25, or 1.0 when the defeated side surrendered (second list only; the first list uses 1.0). The NavalDLC renormalisation divides it out again.

• Both lists are renormalised by their own sums, so River Raider only shifts captures between winning parties; a sole winner gains nothing.

Ship loot score

ship_loot_score: each winner party's score for receiving defeated ships. Consumer NavalDLCBattleRewardModel::PartyLootShipScore, read by DistributeDefeatedPartyShipsAmongWinners (NavalDLC, replaces the default) to split defeated ships among the winner parties. Base contribution, explained number, no clamp, rounded.

ship_loot_score = round((contribution + men + leader_bonus + leader_clan_tier_term + party_clan_tier_term) · (1 + Σ factors))

• contribution: the party's contribution to the battle. men: the party's total man count.
• leader_bonus: 50000 for a kingdom leader, else 20000 for a clan leader, else 0.
• leader_clan_tier_term: when the leader has a clan, 5000 at the lowest clan tier up to 10000 at the highest, linear in the tier. party_clan_tier_term: the same for the party's actual clan. A lord party usually gets both.

• Gilded Purse differs: it raises the share score used to split defeated ships among winners; no capture-chance roll changes, so a sole winner gains nothing.

Loot share

battle_loot_share naval terms (formula on Battles):

Ship costs

Upgrade piece cost

ship_upgrade_cost: the cost of a ship upgrade piece. GetShipUpgradePieceCost (NavalDLC, replaces the default) returns 0 when the piece is already unlocked or installed in a slot, else the piece value from NavalDLCShipCostModel::GetShipUpgradePieceValueInternal. Base piece_value, sequential, no clamp, rounded.

v1 = piece_value                          light / medium / heavy value by hull type 0 / 1 / 2
v2 = v1 · (1 + Σ factors)                 party is mobile
v3 = v2 · 0.9                             Royal Navy Prerogative
v4 = v3 · 0.01                            neither party argument is in the player clan
ship_upgrade_cost = round(v4)

• Master Shipwright: the same piece value also feeds the ship base value, so it also lowers ship trade value and repair cost (broader than the tooltip).

Worked example.

The player's party buys an upgrade piece whose hull-class value is 1000. The party's First Mate has Master Shipwright, and the player clan is the ruling clan of a kingdom with Royal Navy Prerogative. Inputs: piece value 1000.

With these inputs, ship upgrade piece cost is 630.0000.

Repair cost

ship_repair_cost: the cost to repair a ship. Consumer NavalDLCShipCostModel::GetShipRepairCost (NavalDLC, replaces the default). Base ship_base_value · missing_hp_ratio · 0.25, explained number, no clamp, not rounded.

missing_hp_ratio = (max_hit_points − hit_points) / max_hit_points
ship_base_value  = hull_value · (0.01 if the party is not in the player clan) + 0.3 · Σ slots best piece value
ship_repair_cost = ship_base_value · missing_hp_ratio · 0.25 · (1 + Σ factors)

• best piece value: per hull slot, the value of the installed piece or a larger unlocked matching piece, from the upgrade piece value above. Master Shipwright, Royal Navy Prerogative and the 0.01 non-player factor therefore also act on this part.
• The perk factor needs the party to have a mobile party.

Ship deployment and handling

Deployment limit

ship_deployment_limit: ships a party can deploy in a naval battle. Consumer NavalDLCShipDeploymentModel::GetShipDeploymentLimit (NavalDLC). Base 3, explained number, no clamp, truncated to an integer.

ship_deployment_limit = trunc(base + Σ adds)        base = 3, or 8 with the ignore-deployment-limits setting on

• This is the per-battle deployment limit. No party ship-count cap reads these perks.

Sail force, oar force, main deck crew

NavalMissionShipParametersModel (campaign missions). NavalCustomBattleMissionShipParametersModel (custom battles) has identical sail and oar methods; its main deck method has no terms. Only NavalCustomGame::InitializeGameModels (0xfe) creates it, so its Windborne, Chain to Oars and wind bonus sites are dead in the campaign.

ship_sail_force     = base_sail_force · (1 + Σ factors)
ship_oar_force      = max(0, base_oar_force_multiplier · (1 + Σ factors))
main_deck_crew_size = min(ceil(main_deck_crew_capacity · (1 + Σ factors)), total_crew_capacity)

• base_sail_force: the base sail force magnitude argument. Terms only when the ship's captain agent has a campaign character.
• base_oar_force_multiplier: the base multiplier argument; floored at 0.
• main_deck_crew_capacity, total_crew_capacity: the ship's main deck and total crew capacity. Custom battles: min(ceil(main_deck_crew_capacity), total_crew_capacity).

• Shipmaster skill: wind bonus differs: the ship captain agent's own Shipmaster skill is used, not the party Navigator's.
• Popular Captain: every ship whose first unit is from the leader's party gets it, not only the leader's own ship (broader than the tooltip).

Ship collisions

ship_collision_stagger (ShipCollisionOutcomeLogic::HandleAgentActions): when ships collide, every agent on the hit ship within 30 m of the impact point gets a stagger strength

s = impact · 0.15 · 30 / (distance + 0.1) · (0.5 + 0.5 · random) · 100 / (mariner + 100)

• impact: the collision strength passed by the logic; distance: metres from the impact point; random: uniform 0..1; mariner: the agent's effective Mariner.
• s ≤ 1: nothing. The ship's pilot is capped at 2. Otherwise a stagger animation, light below 2, medium below 3, heavy from 3, in the impact's direction relative to the agent's movement.

Game code

• NavalDLC.GameComponents.NavalMissionSiegeEngineCalculationModel.il: CalculateReloadSpeed, CalculateDamage, CalculateShipSiegeWeaponAmmoCount.
• TaleWorlds.MountAndBlade.ComponentInterfaces.DefaultSiegeEngineCalculationModel.il: base CalculateReloadSpeed, CalculateDamage.
• Helpers.PerkHelper.il: the captain perk helper (Captain-role halves only).
• TaleWorlds.CampaignSystem.Party.MobileParty.il: HasPerk (Captain role always false).
• NavalDLC.GameComponents.NavalBattleMoraleModel.il: CalculateMoraleOnRamming, CalculateMoraleChangeOnShipSunk, GetEffectiveInitialMorale, CalculateMaxMoraleChangeDueToAgentIncapacitated.
• NavalDLC.Missions.MissionLogics.NavalAgentMoraleInteractionLogic.il: OnShipRammed, OnShipSunk.
• TaleWorlds.MountAndBlade.AgentComponentExtensions.il: GetMorale, ChangeMorale.
• TaleWorlds.CampaignSystem.Naval.DefaultFigureheads.il: figurehead effect amounts (Lion, Ram, Viper).
• NavalDLC.GameComponents.NavalDLCCampaignShipDamageModel.il: GetShipDamage.
• NavalDLC.GameComponents.NavalDLCCombatSimulationModel.il: SimulateHit (ship and troop overloads).
• NavalDLC.GameComponents.NavalDLCCombatXpModel.il: GetXpFromHit.
• NavalDLC.NavalPolicies.il: policy texts.
• NavalDLC.GameComponents.NavalDLCBattleRewardModel.il: GetCaptureMemberChancesForWinnerParties, PartyLootShipScore, GetLootItemChancesForWinnerParties.
• TaleWorlds.CampaignSystem.GameComponents.DefaultBattleRewardModel.il: base GetCaptureMemberChancesForWinnerParties.
• NavalDLC.CharacterDevelopment.NavalCulturalFeats.il: Nord loot feat.
• NavalDLC.GameComponents.NavalDLCShipCostModel.il: GetShipRepairCost, GetShipBaseValue, GetShipUpgradePieceCost, GetShipUpgradePieceValueInternal.
• NavalDLC.Missions.MissionLogics.ShipCollisionOutcomeLogic.il: HandleAgentActions, OnMissionTick.
• NavalDLC.GameComponents.NavalDLCShipDeploymentModel.il: GetShipDeploymentLimit.
• NavalDLC.GameComponents.NavalMissionShipParametersModel.il, NavalDLC.GameComponents.NavalCustomBattleMissionShipParametersModel.il: CalculateWindBonus, CalculateOarForceMultiplier, CalculateMainDeckCrewSize.

Changelog

• v1.5.7 (2026-11-12): Combat sections re-verified against v1.5.7 IL: Streamlined Operations, Smooth Operator and Rallying Cry primary now apply; Shipwright's Insight primary is the shooter's own perk; Terror of the Seas applies its secondary half to morale; the second capture list is renormalised by its own sum; Terror (Crossbow) no longer skips parties at sea.
• v1.4.8 (2026-11-11): Ship collision stagger and its Mariner reduction added.
• v1.4.8 (2026-11-11): Custom-battle ship parameter sites marked dead; hull size factor folded into the simulated-hit base.
• v1.4.8 (2026-11-11): First version from IL.