Summary at a glance
Goal: Achieve naval supremacy and use blockades to devastate enemy economies and control.
Do this first:
- Blockade enemy trade hubs immediately at war start
- Build balanced fleets (50-60% heavy, 25-30% light, 15-20% transport)
- Rotate fleets back to ports every 6-12 months for repairs
Pitfall to avoid: Neglecting navy even as a land nation. Basic naval capacity is essential for coastal defense and trade protection.
Naval warfare in EU5 is completely redesigned from EU4, with blockades playing a devastating strategic role. This guide covers naval combat, fleet composition, and the powerful blockade mechanics.
Naval Combat Basics
Ship Types
Heavy Ships
Capital ships with high combat power and blockade capacity
- High cannons, hull, and crew
- Expensive but dominant in battle
- Best blockade capacity
- Examples: Carracks, Galleons, Ships of the Line
Light Ships
Fast, cheap ships for trade protection and patrol
- Moderate combat power
- Good blockade capacity
- Best for trade route protection
- Examples: Sloops, Frigates, Corvettes
Galleys
Coastal warfare specialists
- Strong in inland seas (Mediterranean, Baltic)
- Weak in oceans
- Moderate blockade capacity
- Cheap maintenance
Transports
Non-combat ships for troop movement
- No combat ability
- Essential for overseas wars
- Very low blockade capacity
- Vulnerable to enemy fleets
Naval Combat Mechanics
Naval battles use similar mechanics to land battles:
- Flanking System: Ships on flanks can envelope enemy center
- Morale: Ships retreat when morale reaches zero
- Reserve System: Reinforcements join from reserves
- Casualties: Ships can be damaged, captured, or sunk
Combat Width: Determined by admiral skill and technology
- Higher tech = wider combat width = more ships engaged simultaneously
Terrain: Sea zones have different characteristics
- Inland Seas: Favor galleys
- Open Ocean: Favor heavy ships
- Coastal: Balanced
Fleet Composition
Early Game (Age of Traditions - Renaissance)
Balanced Fleet:
- 40% Heavy Ships (Carracks)
- 30% Light Ships (Sloops)
- 20% Galleys (if Mediterranean/Baltic)
- 10% Transports
Total Size: 20-40 ships for regional power
Mid Game (Age of Discovery - Reformation)
Dominant Fleet:
- 50% Heavy Ships (Galleons)
- 30% Light Ships (Frigates)
- 20% Transports (for global wars)
Total Size: 50-80 ships for global power
Late Game (Age of Absolutism - Revolutions)
Global Fleet:
- 60% Heavy Ships (Ships of the Line)
- 25% Light Ships (Corvettes)
- 15% Transports
Total Size: 100+ ships for naval dominance
Blockades: The Devastating Mechanic
How Blockades Work
When your fleet blockades an enemy port, it:
- Reduces Control: -10% to -50% control in blockaded location
- Cuts Supply: Blocks food and resource imports
- Stops Trade: Eliminates trade income from location
- Reduces Maritime Presence: Lowers enemy naval influence
- Spreads Internally: Control loss radiates to inland provinces connected through that port
Blockade Efficiency: Based on your blockade capacity vs. location's blockade requirement
Blockade Capacity
Each ship has a blockade capacity value:
- Heavy Ships: 8-12 capacity
- Light Ships: 4-6 capacity
- Galleys: 3-5 capacity
- Transports: 1 capacity
Blockade Requirements
Locations have varying blockade requirements based on:
- Population: Higher population = higher requirement
- Development: Higher development = higher requirement
- Port Infrastructure: Better ports = higher requirement
- Location Rank: Cities > Towns > Rural
Examples:
- Small coastal village: 5 capacity required
- Medium port town: 20 capacity required
- Major trade hub (Constantinople, Venice, London): 100+ capacity required
Effective Blockading Strategy
Target Selection:
- Enemy Trade Hubs: Maximum economic damage
- Supply Ports: Cut off army supplies
- Capital Regions: Reduce administrative efficiency
- Coastal Fortifications: Prevent supply during sieges
Fleet Assignment:
- Assign 20-40 ships per major port
- Use automated "Blockade" mission for convenience
- Rotate fleets to avoid attrition
Maritime Presence
Maritime Presence is a new EU5 mechanic representing naval dominance in sea zones.
How It Works
Effects of High Maritime Presence:
- +10% to +30% trade income in connected regions
- +5% to +15% control in coastal provinces
- Faster naval movement in the region
- Improved blockade efficiency
Building Maritime Presence:
- Patrol Fleet Mission: Assign fleets to "Patrol Seas" mission
- Trade Posts: Build trade posts in coastal cities
- Light Ships: More effective per ship than heavy ships for presence
- Naval Traditions: Certain ideas and reforms boost presence
Strategic Use: Maintain maritime presence in your core trade regions and blockade zones
Patrol Seas Mission
Purpose: Increase maritime presence during peacetime
How to Use:
- Select fleet
- Assign mission: "Patrol Seas"
- Select sea zone to patrol
- Fleet will patrol automatically, increasing presence
Naval Range & Attrition
Naval Range
Naval range limits how far your fleets can operate from your ports.
Factors:
- Base range: 400-600 (varies by nation)
- Technology: +50 to +200 range per age
- Naval ideas: +100 to +300 range
- Exploration advances: +200 to +500 range
Strategy: Establish naval bases in strategic locations to extend range
Naval Attrition
Fleets take attrition when:
- Outside friendly port range: 5% attrition per month
- In enemy sea zones: 10% attrition per month
- Blockading hostile coasts: 3% attrition per month
- Storms: Random 5-15% attrition
Repair Options:
- In friendly port: 10% repairs per month (free)
- Adjacent to friendly port: 5% repairs per month (small cost)
- Advanced tech: Repair at sea up to 50% (Age of Revolutions)
Naval Warfare Strategy
Offensive Naval Strategy
Goal: Achieve naval supremacy, then leverage it
Steps:
- Build Superior Fleet: Outnumber enemy by 1.5:1 ratio
- Destroy Enemy Navy: Hunt and destroy enemy fleets
- Establish Blockades: Blockade all major enemy ports
- Maintain Presence: Patrol sea zones to prevent rebuilding
- Support Land Wars: Transport troops, cut enemy supply
Best For: Maritime nations (England, Venice, Portugal, Ottomans)
Defensive Naval Strategy
Goal: Protect trade and prevent invasions
Steps:
- Build Balanced Fleet: Match 70% of enemy fleet size
- Protect Home Waters: Focus on coastal defense
- Convoy Raiding: Use light ships to disrupt enemy trade
- Strategic Retreats: Avoid decisive battles, preserve fleet
- Port Defense: Keep fleet in port to prevent blockades
Best For: Land-focused nations with some coastline
Trade Protection Strategy
Goal: Maximize trade income through naval dominance
Steps:
- Build Light Ship Fleet: 60% light ships, 40% heavy
- Patrol Trade Routes: Assign fleets to patrol trade nodes
- Increase Maritime Presence: Build trade posts
- Convoy Protection: Protect own merchants
- Convoy Raiding: Raid enemy trade when at war
Best For: Trade-focused nations (Venice, Holland, Genoa)
Combined Arms: Navy + Army
Amphibious Operations
Landing Troops: Use transports to land armies on enemy coasts
Requirements: Naval supremacy in landing zone
Strategy: Land behind enemy armies, capture undefended provinces
Siege Support
Naval Bombardment: Fleets adjacent to coastal sieges provide +1 to +3 siege bonus
Blockade: Cutting supply to coastal forts speeds surrender
Strategy: Always bring navy to coastal sieges
Supply Lines
Sea Supply: Armies can be supplied through friendly coastal provinces
Blockade Impact: Enemy blockades cut your army supply
Strategy: Maintain naval superiority in supply-critical sea zones
Common Mistakes
- Neglecting Navy: Even land nations need basic naval capacity for coastal defense and trade protection.
- Wrong Fleet Composition: Don't build all heavy ships. Light ships are cost-effective for blockades and trade.
- Ignoring Blockades: Blockading enemy trade hubs can end wars faster than land battles.
- Poor Fleet Positioning: Keep fleets near friendly ports to minimize attrition.
- Not Repairing: Damaged fleets are weak fleets. Rotate home for repairs regularly.
- Forgetting Naval Range: Don't send fleets beyond your naval range without forward naval bases.
Quick Reference
- Optimal Fleet Size: 20-40 ships (small nation), 50-80 (regional power), 100+ (global power)
- Blockade Priority: Trade hubs > Capital ports > Supply ports > Minor harbors
- Ship Ratio: 50-60% Heavy, 25-30% Light, 15-20% Transport (general purpose)
- Patrol Mission: Use during peacetime to build maritime presence
- Repair Frequency: Every 6-12 months, rotate fleets
- Attrition Threshold: Retreat when fleet reaches 50% strength
- Blockade Efficiency: Need 100% of location's blockade requirement for full effect