On Towards the Stars: Boats and Coasts

[This post is part of a larger strategy guide for Civilization 6]

I generally play Pangaea games, in large part because it decreases the impact of a good random start and allows other players to actually interact. But even on Pangaea, there are times when you're going to need boats, and a lot of them. Playing coastal and island games are different enough that I felt it called for it's own subsection, so here we are.

Navy power scaling

Unlike most of the rest of the military tech tree, boats/navy units have massive power disparities that make timing pushes really devastating. For example, the earliest boat, the Galley, has a military strength of 30 at a time when an undefended coastal city generally has strength 10. 

Similarly, the first navy upgrade available (Caravels) have a whopping 55 melee strength — a difference of 25 strength against the galley. By comparison, upgrading warriors to swordsmen is a difference of 15 (20 melee strength to 35 melee strength), while swordsmen to man-at-arms is only a difference of 10 (35 melee strength to 45 melee strength).

Every era has a policy card that gives you a whopping 100% production boost to building ships. In the early game, it is shockingly easy to rush a few galleys and take out at least one coastal city or city state. That said, the same power imbalances that make a navy strong also make it surprisingly difficult to retain broad control of the oceans. An opponent who rushes a few Caravels can quickly decimate a fleet of galleys. In my opinion, to really control oceans, you need to be willing to wage a very aggressive war by preventing opponents from ever even getting on the water. 

Coastal cities

Coastal cities kinda suck compared to inland ones. They generally don't have access to rivers, so they start very housing capped. And ocean tiles generally are lower resource value than land tiles, and on average half of a coastal city's tiles will be on the water. All of this together means it takes a longer amount of time for a coastal city to come online. 

If you have a coastal city — a city with any significant amount of ocean tiles — you should basically immediately build a harbor and a lighthouse. The lighthouse

• Gives you extra housing

• Gives all ocean tiles +1 food

• Gives you an extra trade route capacity

And a few other things. This is generally enough to get your coastal city going, especially if you don't have fresh water. Depending on your available tiles, I also recommend getting a builder to improve coastal amenities and bonus resources as soon as possible. They will have an outsized impact on the coast compared to the rest of your cities. 

One risk of settling coastal is that you may end up with barbarian boats fucking with your tiles. Because galleys are so strong, barbarian navies can pretty easily take and raze unprotected cities. Tldr: build a galley, at least one. You'll get era score and enough protection to make it worthwhile. 

Coastal cities really come alive when you research Shipyards and Cartography. The former, when built, gives all ocean tiles +1 production. The latter in BBG unlocks the fishery improvement, which essentially acts as a stronger farm. Together these let your coastal cities explode in housing, pop, and production. If I have a lot of coastal cities, I try to time getting to Cartography with getting feudalism on the civics tree, so that I can take advantage of the Serfdom policy card (+2 builder charges) and carpet my oceans with fisheries.

Late game navy should basically be all ranged

Once you unlock frigates, you basically don't need to build naval melee units (caravels, ironclads, destroyers). Naval melee is not that strong against naval ranged, and their upgrade tree leaves much to be desired. By contrast, naval units from the frigate up tend to be very powerful siege units for their era, and because they are ranged they can lend critical support to conflict on land without as much risk of counter fire. Note that later naval units — like the battleship or missile cruiser — get 3 range instead of the usual 2, making it even easier to take out walled cities without risking counter attack. 

Misc other notes

• I didn’t really discuss raiders (privateers, submarines, nuclear subs) mostly because I don’t think they are that good. Their unique gimmick is that they are invisible unless right next to an enemy tile. That’s great and all, but if you ever try and use them — say, by attacking — they lose their movement! I think that you should definitely build nuclear subs if you need to position nukes over water, but otherwise I basically never build these¹.

• Get Venetian Arsenal (+100% production to all boats) if you can. This wonder is just absolutely busted in the base game. With BBG it's a bit more balanced, but still very strong — with this wonder and the right cards, you can effectively produce at 200% speed.

  

• Try to get a Mausoleum too. I've already mentioned that this is a very strong wonder due to it's +1 Great Engineer charge bonus. On a city with a ton of coast, Mausoleum acts like Petra and can turn a regular city into a super city.

1. Victoria is the one exception. Her unique unit, the Sea Dog, has a unique boat capture mechanic that is absolutely deadly and can help your navy double in size during any war.