Bannerlord mechanics

Mariner guide

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

This guide explains what the Mariner skill and every Mariner perk really do in game v1.5.7: how you and your crew fight on ships, how the skill strips away the penalties of fighting on a rolling deck, what the party-leader and governor halves do on the campaign map, and which perks behave differently from their tooltips. Mariner needs the NavalDLC module: the skill, its perks and its skill effects all come from NavalDLC and do not exist without it. NavalDLC extends the agent damage, agent stats, battle morale, hit experience, military power, troop training, prisoner recruitment, raid, militia and armor and strike magnitude models, and extends and replaces parts of the battle reward, combat simulation and encounter models. StoryMode extends the hit experience and prisoner recruitment models, and extends and replaces parts of the battle reward models in the story campaign.

For exact formulas, edge cases and links to the game code, see the deep dives: Naval battles (ship-sunk morale, morale terms on ships, XP per hit at sea, convoy loot), Naval campaign (raids, bribes and forcing bandits to join, battle XP, prisoner conformity, militia), Combat damage (damage perks, armor, cleave, missiles and shields, sail fire), Combat agent stats (naval penalties, handling, breath hold) and Battles (starting morale, kill morale, simulated battles, hero strength). The other two naval skills have their own guides: Boatswain and Shipmaster.

Each perk has two halves. The primary half usually helps you personally; the secondary half helps others when you hold a role: captain (the troops in the formation you lead in battle), party leader (your whole party), army commander (the army you lead) or governor (the settlement you govern). The verdict after each half says how the code compares with the tooltip:

Two Mariner perk halves are unused (Terror of the Seas primary, Brute Force secondary); none is ui_only. One skill effect is unused.

What unlocks what

Every 25 points of Mariner opens a new pair. You pick one perk of each pair; the other is locked for that hero.

Mariner Perk A Perk B
25 Pirate's Prowess: melee handling at sea; loot from merchant convoys Rolling Thunder: steadier aim on ships; pirate prisoners turn faster
50 Brute Force: kick and bash damage; naval raid loot (never read) Shield Breaker: crew shield damage at sea; raid speed from the sea
75 Axe of the North Wind: axe damage at sea; starting morale of mariner troops Sunny Disposition: sword damage at sea; starting morale of other troops
100 Enemy of the Wood: enemy morale loss per sunk ship; crew fire damage to sails Naval Fighting Training: companion XP at sea; veteran militia in port settlements
125 Rallying Cry: party starting morale in naval battles; less melee damage on own ships Terror of the Seas: enemy morale loss per kill (never applies); less melee damage on enemy ships
150 Shattering Blow: melee armor penetration, you and crew Shattering Volley: ranged armor penetration, you and crew
175 Arr!: force pirates to join at sea; mariner troop XP after battles at sea Pirate Hunter: send-troops edge against pirates; regular troop XP after battles at sea
200 Boarding Master: melee damage on enemy ships, you and crew Home Turf Advantage: melee damage on your own ships, you and crew
225 Crew of Spears: javelins and throwing axes through shields; crew throwing damage Mighty Blows: better two-handed cleave; crew two-handed damage
250 The Sky's Fury: your ranged damage at sea; crew bow and crossbow damage Warrior's Might: your melee damage at sea; crew throwing damage

How the damage perks add up

Most Mariner perks are damage percentages on one blow. The game first applies the land perks (One Handed, Two Handed, Bow and the other weapon skills, banners) as one sum, then the naval perks (Mariner, Shipmaster, Boatswain) as a second sum on that result.

Damage = inflicted damage × (1 + sum of land percentage bonuses) × (1 + sum of naval percentage bonuses)

Crew damage reductions (Rallying Cry, Terror of the Seas) work the same way on the damage taken. The "crew" halves read the captain of the attacking troop's formation; the captain's own blows use the personal halves instead. The damage formulas and all other sources are in Amplifications.

Mariner 25: Pirate's Prowess or Rolling Thunder

Pirate's Prowess

Rolling Thunder

Worked example. Your party is at sea with a pirate prisoner. You lead it with Leadership 100 and Rolling Thunder. Conformity starts at 10 per hour, your Leadership adds 0.05 per point (+5.0000 here), then Rolling Thunder adds 50% of the total:

A party at sea holding a pirate prisoner, led by a hero with Leadership 100 and Rolling Thunder.

Step Source Stage Change Running value
Base Prisoner conformity gained per hour base 10.0000
1 Party leader Leadership (conformity) add +5.0000 15.0000
2 Rolling Thunder factor +50% +7.5000 22.5000
Result Prisoner conformity gained per hour 22.5000

With these inputs, prisoner conformity gained per hour is 22.5000.

The prisoner gains 22.5000 conformity per hour instead of 15.0000.

Which one? Pirate's Prowess acts on melee weapons in naval battles and on loot from merchant convoys. Rolling Thunder acts on ranged weapons in naval battles and on pirate prisoners held at sea.

Mariner 50: Brute Force or Shield Breaker

Brute Force

Worked example. Your party raids a village from the sea, with or without Brute Force:

A party at sea raiding a village, led by a hero with no Mercy trait. Brute Force is not needed; every raiding party at sea gets the same bonus.

Step Source Stage Change Running value
Base Raid loot multiplier base 1.0000
1 Raiding party at sea add +0.5000 1.5000
Result Raid loot multiplier 1.5000

With these inputs, raid loot multiplier is 1.5000.

With the multiplier at 1.5000, each looted item reaches your party with a chance of 0.5 × 1.5000 instead of 0.5 × 1.0000.

Shield Breaker

Worked example. Your party of 100 troops raids a village alone from the sea for one hour:

A party of 100 troops raids a village alone from the sea for one hour, led by a hero with Shield Breaker. Inputs: troops 100, hours 1.

Step Source Stage Change Running value
Base Hourly raid damage to a village base 0.0167
1 Shield Breaker factor +25% +0.0041 0.0208
Result Hourly raid damage to a village 0.0208

With these inputs, hourly raid damage to a village is 0.0208.

Which one? Brute Force's kick bonus is a sea-only perk like the rest, and its raid half does nothing: the sea raid loot bonus comes without the perk. Shield Breaker adds crew shield damage in naval battles and +25% raid speed from the sea.

Mariner 75: Axe of the North Wind or Sunny Disposition

Axe of the North Wind

Sunny Disposition

The two secondary halves split your party by one test: is the troop a mariner or not. Together they would cover everyone, but you can hold only one. Starting morale and the other sources are in Initial battle morale.

Which one? The primaries differ by weapon (melee axes or swords); the secondaries differ by troop group (mariner troops or everyone else).

Mariner 100: Enemy of the Wood or Naval Fighting Training

Enemy of the Wood

Worked example. A port town whose governor, present in the town, has Citizen Militia and Naval Fighting Training:

A town with a port whose governor, present in the town, has Citizen Militia and Naval Fighting Training. The chance is a 0-1 probability.

Step Source Stage Change Running value
Base Chance that a spawned militia troop is a veteran base 0.0000
1 Citizen Militia add +0.2000 0.2000
2 Naval Fighting Training factor +10% +0.0200 0.2200
Result Chance that a spawned militia troop is a veteran 0.2200

With these inputs, chance that a spawned militia troop is a veteran is 0.2200.

The +10% scales whatever chance the other sources give: here 0.2000 becomes 0.2200.

Mariner 125: Rallying Cry or Terror of the Seas

Rallying Cry

Terror of the Seas

Which one? Both secondaries give −10% melee damage taken; Rallying Cry covers defending your own decks, Terror of the Seas covers boarding and also cuts enemy morale loss. Only Rallying Cry has a working primary.

Mariner 150: Shattering Blow or Shattering Volley

Armor penetration here removes part of the armor of the body part that is hit before damage is computed. Each perk removes its own percentage of the armor, and the percentages add together (Vandal from Two Handed and the other weapon-skill penetration perks included). See Adjusted armor.

Shattering Blow

Shattering Volley

Which one? Shattering Blow for melee, Shattering Volley for ranged; the numbers are the same, and both are sea only.

Mariner 175: Arr! or Pirate Hunter

Arr!

Pirate Hunter

Which one? Arr! decides whether you can recruit bandits at sea and trains mariner troops; Pirate Hunter helps simulated naval battles you start against bandits and trains every regular troop.

Mariner 200: Boarding Master or Home Turf Advantage

The game sorts every melee fighter in a naval battle by the ship under their feet: an enemy ship, or a ship of their own side (allied ships included).

Boarding Master

Home Turf Advantage

Which one? Boarding Master if you board enemy ships; Home Turf Advantage (+20% instead of +15%) if you fight off boarders on your own decks.

Mariner 225: Crew of Spears or Mighty Blows

Crew of Spears

Mighty Blows

Mariner 250: The Sky's Fury or Warrior's Might

The Sky's Fury

Warrior's Might

Skill effects

The Mariner skill itself has four effects.

What the skill level itself does

The game also reads your Mariner level directly, without any perk. Effects that depend on any skill level are listed once in the skills guide.

What it affects What the level does Level needed Conditions Verdict
Ship collision stagger strength on agents Ship collision stagger on a soldier is multiplied by 100 ÷ (Mariner + 100): half at Mariner 100. — Mission: naval battle works

Who the perks work for

Who counts as you, a relative or a wanderer, and why some halves skip one of them, is explained in the Skills guide.

Every other Mariner perk half and skill effect works for every hero: you, relatives and wanderers.

Perk Half Works for Where the hero has to be
Brute Force secondary nobody: never read in play, or only shown in the interface —
Naval Fighting Training secondary relatives and wanderers, not you governor
Terror of the Seas primary nobody: never read in play, or only shown in the interface —
Naval Auto Battle Combat Penalty Negation Effect — nobody: never read in play, or only shown in the interface —

All effects at a glance

Every effect site of the Mariner perks, skill effects and skill level. Values are what each site applies; a value that grows with skill is shown at the perk's required skill (skill effects and skill levels: per skill point). ×N marks N identical sites.

Perk Half Game number Stage Value Conditions Verdict
Pirate's Prowess primary Melee weapon handling multiplier factor +25% Item: melee weapon; mission: naval battle; role: personal works
Pirate's Prowess secondary Winner party's share of the defeated party's loot factor +30% Role: party leader; victim: naval caravan works
Rolling Thunder primary Naval AI shooter error addend factor -30% Item: ranged weapon; mission: naval battle; role: personal works
Rolling Thunder primary Naval ranged movement accuracy penalty factor -30% Item: ranged weapon; mission: naval battle; role: personal works
Rolling Thunder secondary Prisoner conformity gained per hour factor +50% Role: party leader; victim: pirate works
Brute Force primary Blow damage after attacker amplifications factor +50% Attack: kick or bash; role: personal works
Brute Force secondary Raid loot multiplier factor +20% — unused
Shield Breaker primary Blow damage after attacker amplifications factor +30% Attack: shield hit; mission: naval battle; role: captain works
Shield Breaker primary Hero power modifier in simulation add +0.01 Mission: simulation differs
Shield Breaker secondary Hourly raid damage to a village factor +25% × party share Party: at sea; role: party leader differs
Axe of the North Wind primary Blow damage after attacker amplifications factor +20% Item: axe, melee weapon; mission: naval battle; role: personal differs
Axe of the North Wind secondary Agent initial battle morale add +20 Mission: naval battle; role: party leader; troops: mariner works
Sunny Disposition primary Blow damage after attacker amplifications factor +20% Item: melee weapon, sword; mission: naval battle; role: personal works
Sunny Disposition secondary Agent initial battle morale add +20 Mission: naval battle; role: party leader; troops: not mariner works
Enemy of the Wood primary Morale change of a sunk ship's team add -10 Mission: naval battle; party: in army; role: army commander works
Enemy of the Wood secondary Fire damage to a ship sail factor +25% Mission: naval battle; role: captain; victim: sail works
Naval Fighting Training primary Combat XP from one hit factor +10% Hero: companion; mission: naval battle; role: party leader differs
Naval Fighting Training secondary Chance that a spawned militia troop is a veteran factor +10% Role: governor; settlement: port works
Rallying Cry primary Hero power modifier in simulation add +0.02 Mission: simulation differs
Rallying Cry primary Agent initial battle morale factor +20% Mission: naval battle; role: party leader works
Rallying Cry secondary Blow damage after victim reductions factor -10% Item: melee weapon; mission: naval battle; role: captain; victim: on own ship works
Terror of the Seas primary Morale loss of the casualty's side when an agent falls factor +20% — unused
Terror of the Seas secondary Blow damage after victim reductions factor -10% Item: melee weapon; mission: naval battle; role: captain; victim: on enemy ship works
Terror of the Seas secondary Morale loss of the casualty's side when an agent falls factor -10% Mission: naval battle; role: captain differs
Shattering Blow primary Victim armor after attacker penetration effects factor +50% Item: melee weapon; role: personal works
Shattering Blow secondary Victim armor after attacker penetration effects factor +50% Item: melee weapon; role: captain works
Shattering Volley primary Victim armor after attacker penetration effects factor +50% Item: consumable weapon; role: personal works
Shattering Volley secondary Victim armor after attacker penetration effects factor +50% Item: consumable weapon; role: captain works
Arr! primary Chance a weaker party accepts a bribe add +0 Role: personal; victim: pirate differs
Arr! primary Player can force bandits to join override on Hero: main hero; party: at sea, main party; role: personal works
Arr! secondary Troop experience gained from a battle factor +15% Role: party leader; troops: mariner works
Pirate Hunter primary Side advantage in simulated battles factor +20% Mission: simulation; party: attacker; role: party leader; victim: bandit party differs
Pirate Hunter secondary Troop experience gained from a battle factor +10% Role: party leader; troops: regular works
Boarding Master primary Blow damage after attacker amplifications factor +15% Item: melee weapon; mission: naval battle; role: personal; ship: enemy ship works
Boarding Master secondary Blow damage after attacker amplifications factor +15% Item: melee weapon; mission: naval battle; role: captain; ship: enemy ship works
Home Turf Advantage primary Blow damage after attacker amplifications factor +20% Item: melee weapon; mission: naval battle; role: personal; ship: own ship works
Home Turf Advantage secondary Blow damage after attacker amplifications factor +20% Item: melee weapon; mission: naval battle; role: captain; ship: own ship works
Crew of Spears primary Missile continues after breaking a shield override on Item: throwing axe; mission: naval battle; role: personal works
Crew of Spears primary Missile weapon flags on launch override set to 1 Item: javelin; mission: naval battle; role: personal works
Crew of Spears secondary Blow damage after attacker amplifications factor +15% Item: throwing weapon; mission: naval battle; role: captain works
Mighty Blows primary Two-handed cleave momentum loss factor -50% Attack: swing; item: two handed weapon; role: personal works
Mighty Blows secondary Blow damage after attacker amplifications factor +15% Item: two handed weapon; mission: naval battle; role: captain works
The Sky's Fury primary Blow damage after attacker amplifications factor +15% Item: consumable weapon; mission: naval battle; role: personal works
The Sky's Fury secondary Blow damage after attacker amplifications factor +15% Item: bow, crossbow; mission: naval battle; role: captain works
Warrior's Might primary Blow damage after attacker amplifications factor +20% Item: melee weapon; mission: naval battle; role: personal works
Warrior's Might secondary Blow damage after attacker amplifications factor +20% Item: throwing weapon; mission: naval battle; role: captain works
Naval Auto Battle Combat Penalty Negation Effect — Damage of one simulated troop hit base +0.5 per point Mission: simulation; role: party leader unused
Naval simulation advantage — Side advantage in simulated battles factor +0.1% per point Mission: simulation; role: party leader differs
Naval Battle Combat Penalty Negation Effect — Naval AI shooter error addend factor -0.5% per point Item: ranged weapon; mission: naval battle; role: personal works
Naval Battle Combat Penalty Negation Effect — Naval damage penalty factor -0.5% per point Mission: naval battle; role: personal works
Naval Battle Combat Penalty Negation Effect — Naval external acceleration accuracy penalty factor -0.5% per point Item: ranged weapon; mission: naval battle; role: personal works
Naval Battle Combat Penalty Negation Effect — Naval ranged inaccuracy penalty factor -0.5% per point Item: ranged weapon; mission: naval battle; role: personal works
Naval Battle Combat Penalty Negation Effect — Naval ranged movement accuracy penalty factor -0.5% per point Item: ranged weapon; mission: naval battle; role: personal works
Naval Battle Combat Penalty Negation Effect — Naval ranged rotational accuracy penalty factor -0.5% per point Item: ranged weapon; mission: naval battle; role: personal works
Naval Battle Combat Penalty Negation Effect — Naval deck movement speed penalty factor -0.5% per point Mission: naval battle; role: personal works
Naval battle underwater breathing duration — Underwater breath-hold max duration factor +0% Role: personal differs
Skill level (any skill) — Agent effective skill in battle base skill value — works
Skill level (any skill) — Skill a hero inherits on coming of age base +1 per point — works
Skill level (any skill) — Heir selection points of a clan member add +5 — works
Skill level (any skill) — Maximum troops lost on an issue's alternative solution multiply ×max(0.2, min(0.8, trunc(issue required skill / skill) × 0.1)) Hero: player clan works
Skill level (any skill) — Days an issue's alternative solution takes add +2 × min(10, trunc(issue required skill / skill)) Hero: player clan works
Skill level (any skill) — Failure risk of an issue's alternative solution add -0.005 per point Hero: player clan works
Skill level (any skill) — Troops required for an issue's alternative solution multiply ×max(0.2, min(1.2, issue required skill / skill)) Hero: player clan works
Skill level — Ship collision stagger strength on agents multiply ×100 / (skill + 100) Mission: naval battle works
Skill level (any skill) — Skill is high enough for a perk reset override on Hero: player clan works
Skill level (any skill) — Gold cost to reset the perks of a skill add +40 per point Hero: player clan works
Skill level (any skill) — Persuasion success multiplier factor min(0.2, floor(skill / 250) × 0.2) Hero: main hero works

Practical tips