Naval units are military units, with the exception of Great Admirals, which have water as their native element: they can never move onto a land tile, unless that tile is a City Center, a Canal or submerged due to the rising sea levels. Unlike in Civilization V, no naval units (including Submarines) can move through Ice tiles. Here can be found a list of naval units in Civilization VI.
Moving at sea is significantly easier than moving on land - all tiles here take only 1 Movement to go to, except when the tile is improved by a Polder or contains the Hạ Long Bay. However, as usual, certain technologies are generally required to be able to move at sea at all (notably the Māori have those techs by default). Furthermore, the seas are divided in two types of tiles: Coast tiles, where the waters are close to land and more calm; and the Ocean tiles, which cover most of the map. The Sailing tech allows you to build the first ship in the game, the Galley, but this ship may only move on Coast tiles. The same is valid for the more advanced Quadrireme.
At the same time, most land units may not move on sea at all, until the Shipbuilding tech is developed. Before that, only Builders may Embark with Sailing, and Traders may embark with Celestial Navigation.
No units may enter Ocean tiles until the development of Cartography in the Renaissance Era. At this point even Galleys and Quadriremes are able to enter Ocean tiles. This represents a stark difference with Civilization V, where early game units could never enter Ocean tiles, even when your civilization had progressed enough.
Military naval units, like their land based counterparts, can be organized into powerful permanent unit formations (not to be confused with creating ad hoc temporary escort formations of military and civilian units by stacking). There are currently two types of such formations available in the game:
- Fleet, created by combining two units of a kind. Normally requires the Nationalism Civic. The effect is to increase the Combat Strength by +10 (both Combat and Ranged Strength) above a single unit of the same type. Note that secondary statistics (such as Movement or Range, as well as Anti-Air strength) remain unchanged!
- Armada, created by combining three units of a kind. Normally requires the Mobilization Civic. The effect is to increase the Combat Strength by +17 (both Combat and Ranged Strength) above a single unit of the same type.
Maintenance for the combined units is less than the combined value of the two or three units. The exact values involved seem to depend on the Era of the combined units. Also, it appears that units trained as Fleets, etc. in a city with a Seaport will have their maintenance reduced even more.
Another advantage to Fleets and Armadas is that their maintenance cost is not much higher than for normal units of the same type. This makes it worthwhile forming these advanced formations from a purely economical standpoint: you spend less Gold for maintaining a formation which consists of less units of greater individual strength.
You have two main ways of forming these formations. The first one is to combine existing units: whenever you have two or more identical units in adjacent tiles, a special action will appear in their Action tab, after which you will be prompted to choose which units you want to combine with. The new combined unit inherits the promotions of its most experienced unit (i.e. the one with the highest promotion level at the time you create or expand the formation), and its XP earning rate and unique name (if it has one). Any other promotions which lower-ranking units had before being added to the formation are lost. That means it is a good strategy to combine new, inexperienced units with your veteran ones. If the two units you're combining are the same level but have different promotions, the resultant Fleet or Armada inherits all promotions from both units.
The second way is to train a new unit directly into the higher formation from the start, in a city with a Harbor and a Seaport. This will take more Production, proportional to the increase in Combat Strength a formation provides over a normal unit of this kind. However, it is still faster than creating two or three separate units, then combining them (unless of course you create them in two or three different cities).
Please note that certain Great Admirals can create Fleets or Armadas using their retirement ability.
In Gathering Storm most late-game units also 'consume' strategic resources each turn ( Coal, Oil, Aluminum or Uranium), which amounts to a specific type of maintenance. Fleets and Armadas however still consume the same amount of resources as an individual unit of the type, which makes it even more advantageous to maintain a lesser number of these more advanced formations, instead greater number of simple units of the same type.
|I||Embolon||+7 Combat Strength vs. naval units.||-|
|II||Rutter||+1 sight range.||Helmsman|
|II||Reinforced Hull||+10 Combat Strength when defending vs. ranged attacks.||Embolon|
|III||Convoy||+10 Combat Strength when in a formation.||Rutter or Reinforced Hull|
|III||Auxiliary Ships||Heal outside of friendly territory.||Rutter or Reinforced Hull|
|IV||Creeping Attack||+14 Combat Strength vs. naval raider units.||Convoy or Auxiliary Ships|
|I||Line of Battle||+7 Combat Strength vs. naval units.||-|
|I||Bombardment||+7 Combat Strength vs. district defenses.||-|
|II||Preparatory Fire||+7 Combat Strength vs. land units.||Line of Battle|
|II||Rolling Barrage||+10 Combat Strength vs. district defenses.||Bombardment|
|III||Supply Fleet||Heal outside of friendly territory.||Preparatory Fire or Rolling Barrage|
|III||Proximity Fuses||+7 Combat Strength when defending vs. air attacks.||Preparatory Fire or Rolling Barrage|
|IV||Coincidence Rangefinding||+1 Range.||Supply Fleet or Proximity Fuses|
|I||Loot||+50 Gold from coastal raids (on Standard speed).||-|
|I||Boarding||Obtain Gold from naval victories.||-|
|II||Swift Keel||+1 Movement.||Loot or Homing Torpedoes|
|II||Homing Torpedoes||+10 Combat Strength vs. naval units.||Boarding or Swift Keel|
|III||Observation||+1 sight range.||Swift Keel|
|III||Silent Running||Can move after attacking.||Homing Torpedoes|
|IV||Wolfpack||+1 additional attack per turn.||Observation or Silent Running|
|I||Flight Deck||+1 additional aircraft slot.||-|
|I||Scout Planes||+1 sight range.||-|
|II||Hangar Deck||+1 additional aircraft slot.||Flight Deck or Advanced Engines|
|II||Advanced Engines||+1 Movement.||Scout Planes or Hangar Deck|
|III||Folding Wings||+1 additional aircraft slot.||Hangar Deck or Deck Crews|
|III||Deck Crews||Can heal after attacking.||Advanced Engines or Folding Wings|
|IV||Supercarrier||Heal outside of friendly territory.||Deck Crews or Folding Wings|