Mixing and Matching Land, Sea, and Air Unit Abilities

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By experimenting with unit roles and abilities, a scenario designer can conjure up some fascinating gameplay effects.

by Kobayashi (January 2001)

Opportunity for Innovation

An interesting and enjoyable scenario is more than giving units progressively more attack and defence points. It is more than changing the look of units and it is more than providing a super powerful hero unit that will go round pulverizing the bad guys. One of the more important aspects of a scenario that differentiates the average from the superb is the use of innovative, complimentary but unfamiliar combinations of abilities in unit design. This will allow a player to relive the experience of encountering the unfamiliar and the experience of his first Civ2 game.

Many a time I thought that I had come up with a fantastic unit with new characteristics only to find out later that it didn’t work out as I planned. This has led me to develop the Land, Sea and Air Matrices of Abilities and Domains. In each matrix, the diagonal represents a single ability while the remaining squares represent various combinations of two abilities, coded by color:

  • Grey – combinations that are not available
  • Red – impractical combinations or combinations which have no additional impact.
  • Yellow – workable combinations
  • Pink – combinations applicable under very specific situations
  • Light Blue – standard Civ2 combinations
  • Dark Blue – workable and interesting combinations

Sl landseaair land.png

Sl landseaair sea.png

Sl landseaair air.png


The Land Matrix shows the most number of usable combinations as land is Civ2’s primary domain. Thus a relatively greater amount of flexibility is given to the scenario designer. The few red areas in the matrix are related to the diplomat, trireme and submarine abilities. The grey areas reflect the fact that land units cannot have holds and also show that the settler, diplomacy and trade roles are mutually exclusive. In the case of the latter, this also holds true for sea and air domains.

The Sea Matrix is has many more red areas because sea units are automatically granted many of the abilities of land units like Ignoring Zone of Control, Ignoring City Walls (but not coastal battery) and Amphibious Assault. Other land-based abilities like Alpine are not relevant to sea units. Sea based trade and diplomacy units are also not viable.

There is very little room for manoeuvring when it comes to the Air Matrix. More than half the available slots are not working combinations. You can treat helicopters as if they belong to this matrix as they behave like other air units as far as the effect of abilities is concerned.

The Three Special Roles

This section is broken down into the Settler, Diplomat and Trade roles. One other role, Sea Transport is dealt with in the miscellaneous section but the remaining four roles like Attack and Defend do not entail special traits and have been left out. In general, I will deal with the land, sea and then air domains in that order.

Settler Role (including Engineer)

All settlers, whether land, sea or air, are compatible with most abilities and they can attack like normal units when given attack points. This possibility is often ignored. I seldom come across a fighting settler, let alone an all-powerful hero settler, even in cases where the human player can only play a certain tribe and AI is not a problem.

First, I will deal with land-settlers. An interesting point about land-settlers is that they can be given the power to change land into sea by fiddling with the terrain editor. The strange thing about doing this is that the settler falls asleep immediately after the land below it is changed to sea. Fortunately, you can awake it and move it back to the adjoining land at anytime. The process cannot take more than one turn or the settler wall fall asleep before the job is done. This means you must use the mine (or irrigation) order and not the terraform (engineer) order.

Irrigation and farmland will be lost but roads and railways remain when the land below is changed to sea. Although roads and railways cannot be used for moving purposes, they will still give the normal trade bonuses to nearby cities. In certain cases, like a no road/rail underwater scenario, you can change the look of roads and rail to reflect sea bonuses.

Returning to land to sea conversion. How would any of this be of any use? Well, there could be a scenario where the player needs to dig a canal across a narrow isthmus to allow his armada to move to a different part of the map. Or maybe you can use this to simulate a special starship used to break through an energy barrier in a space scenario. The land beneath cities can also be changed to sea but all units in the city will sleep in perpetuity although they may be awakened each turn.

You can also arrange it such that settlers can change ocean to land. Finding a use for this quaint option is much harder but after much pondering, I have come up with this: You could have a city in the ocean (graphics changed to something appropriate) where everyone has been asleep for a hundred years. You will need to use settlers to do this manually as the change terrain function under the cheat menu does not allow you to change terrain under a city and changing terrain in the events.txt will wipe out all cities and units in the affected areas. When you finally gain an advance that allows you to build a settler unit that can change the ocean back to land, the city can be awakened.

Sea-settlers are more versatile than land-settlers when it comes to changing the domain of terrain. That is because they don’t fall asleep on land and are therefore not limited to single turn transformations. If a sea-settler changes the sea to land, they can move back into the sea on the next turn. Giving them the ability to change land to sea would only have an effect inside cities (unless used in conjunction with para-drop) and as much as I try, I cannot think of any circumstances where this might be useful other than the sleeping beauty scenario outlined earlier.

Air-settlers are even more versatile than land or even sea-settlers when it comes to changing the domain of terrain. After all they may freely move over both land and sea and that makes it logistically easier to change land to sea or vice versa. However, there is a strange side effect of using air-settlers. Even if an air-settler has a certain range (i.e. how many turns in the air), it can complete settler type orders that take much longer that that. Also, after it completes any settler type order, its range counter is reset to zero.

Diplomat Role (including Spies)

Diplomats cannot attack as they will automatically bribe/sabotage instead. Consequently any attack related abilities like fighter, howitzer and missile will have no effect. One interesting ability to add to a diplomat is the para-drop ability. This will allow SAS or SEAL type infiltration teams.

Sea and Air units that are given the diplomacy role cannot function as diplomats and also cannot attack. This means that the idea of a non-land diplomats is a non-starter. Think of this as a fancy way of making barricade units, those with an attack of zero. This is one way to get around the AI auto redundancy algorithm as the barricade would use the diplomacy role.

Trade Role

Unlike diplomats, land trade units can attack and still perform their trade function. If they attack units outside a city, they behave like normal ground units while if they attack a city, they automatically behave as a trade unit. This means that all attack related abilities are compatible with land trade units except the howitzer ability. A useful unit that could be made is an armored car (for banks, not the type used by infantry).

Sea and Air units which are given the trade role function as completely normal units and cannot make trade routes. They also cannot help build wonders. So there is no reason to have non-land trade units.


I will only deal with abilities in the domains where they are not used in a standard game. I assume that things like how a submarine behaves in the sea are common knowledge.

Two Space Visibility

Nothing special to mention here, all units can have this ability without causing problems.

Ignore Zone of Control

Air and Sea units already have this ability built in so it only applies to Land units.

Amphibious Assault (Marine)

Air and Sea units already have this ability built in so it only applies to Land units.


Ground units with the submarine ability cannot attack other ground units and also cannot attack sea units by the shore. In other words, they are no different from a regular ground unit with an attack of zero except for the fact that you will not get the “units with zero attack cannot roles functions. Conceivably, if your settlers are not meant to attack, they could be submarines as well.

Air units with the submarine ability cannot attack any targets over land, even if the target is an air unit and even if you have given the submarine unit fighter ability. This distinction may be useful if you wish to split your air units into trireme type ground based aircraft and long range naval/carrier based aircraft.

Another thing to note about land and air-submarines is that air missiles can rest on them without running out of fuel. But unlike sea based submarines, missiles cannot sleep on a non-sea submarine and when the non-sea submarine moves away, the missile cannot follow automatically.

Attack Air (Fighter)

Nothing special to mention here, except limitations mentioned in other areas. For instance, you can’t give attack air with diplomats as they don’t attack and they can bribe or sabotage units of all domains anyway. Also remember that fighters of any domain in a city scramble against any air attacks so the corresponding message in game.txt needs adjustment if you are using this for land or sea units.


Ground units, even when they are on transports are not affected by the trireme effect. Therefore, it is irrelevant whether you impose the trireme disadvantage or not in ground units.

Note: Strangely enough, the trireme effect works on air units. This combination is effective in keeping aircraft over land as in the early days of flight. You will also need to alter the message in game.txt that appears when a trireme sinks for optimal effect.

Ignore City Walls (Howitzer)

Air and Sea units already have this ability built in so it only applies to Land units.


The concept of a land-based carrier may sound strange at first. But on reflection, it is actually a very versatile combination that can be used in many different settings. It can be used to simulate lots of things in conjunction with missile or air units like a mage who can fire bolts of lightning or a scud launcher.

Sea-carriers need to be mentioned here because there is a special case for the sea-carrier. There are regular sea-carriers and then there are sea-carriers with holds. Generally, the carrier ability takes precedence. A ground unit can move onto a carrier-transport by the shore but when the carrier-transport moves off, the ground unit is left sleeping the sea. The only limited way this quirk might be useful is perhaps as a mine-layer. The mines would be submarine land units with a big defense value and no attack. Moving the mines further away from the home port would require a step by step process. The mine is automatically dropped as the mine-layer moves off. Then the mine can be moved back onto the mine-layer under its own power. When the mine-layer moves off again, the mine would be two spaces away from the home city and so on.

Air Units which are carriers are also unique. They move only one space in a turn irrespective of their movement and range settings. They also never run out of fuel.

As in the case of the non-sea submarines, land-carriers and air-carriers also do not allow missile and air units to sleep on them. As long as the carrier does not move away, the units on top of it will not run out of fuel. This limitation necessitates the creative use of non-sea-carriers. If missiles or aircraft in your scenario have a very short movement value, say 4, it is conceivable that you might need a mobile land based waypoint between cities so that you can move the air units from city to city. Otherwise, your air units would be stuck in the cities which built them. The ability to perpetually refuel air and missile units without the ability of dragging them along when the air-carrier moves would make air-carriers seem more like inexhaustible mid-air refueling tankers.

Para-drop Ability

This is a unique ability that warrants some attention for non-land units. A ship with para-drop ability can only be dropped onto land. Once they are dropped, they cannot move but they can attack adjacent land units. This is roughly equivalent to making bunkers or gun emplacements that are immobile once they are positioned. When used in this manner, certain other abilities have relevance, like the pikeman ability. A variation of this idea is to para-drop zero movement land-carriers or land-submarines. This would solve the problem of left behind air units.

Another way to use the para-drop ability for sea units is to take advantage of the fact that ships can be para-dropped on the shore and thereafter move into the sea on their own power. This could be used to simulate a shipyard city (a city that is set slightly inland and has a pool next to it) that is impregnable from the sea.

An air unit with para-drop ability must also be dropped onto land. Once they are dropped, they can move and attack as per regular air units. The para-dropped distance is not taken into account when determining the movement allowance. Think of this as an afterburner takeoff which takes an air unit beyond its point of no-return (for units with range of 2).

Ignore Terrain (Alpine)

Air units ignore terrain anyway while sea units cannot move on land so this ability only applies to land units.

Double Defence verse Mobile (Pikeman)

The double defence (actually it is only 1.5x defence) only applies to units attacked by land units with movement of 2 or more. There is limited use in the case of air units attacked by fighter ability ground units while sea units have no need of this ability. I have read somewhere that the effect is lessened for units with more than one hit point but I haven’t verified this.

Fundamentalism (Fanatic)

This ability applies equally to units of all domains. Preconditions for building a fanatic do not apply to fanatic type units that do not occupy the fanatic slots.

Destroyed after Attack (Missile)

The missile ability is great to use with land units and when it is combined with the fundamentalist ability, it is ideal for simulating suicide squads. This ability is also great for simulating torpedoes or storms using sea missile units.

Double Defence verse Air (AEGIS)

Nothing special to mention here, all units can have this ability without causing problems.

See Invisible

Nothing special to mention here, all units can have this ability without causing problems.



Only sea units are allowed to have holds and there are no conflicts except in the case of the carrier (as mentioned above). Even a sea-settler can carry troops while it is busy terra-forming the sea.

Units with Zero Movement

Strictly speaking, this is not a combination, but its just too unique an idea to leave out. One way to use these units is as a trigger for an event. Make a sea unit look exactly like the terrain below it and give it zero defence. When the player moves his unit into the square, it will destroy the camouflaged unit and trigger whatever event that is planned. This unit can be placed on land or in the ocean. Why not use a land unit? Because land units generate ZOC.

A second way to use this is as a weak section in a wall. If water is used as impassable terrain as in many dungeon type scenarios, one part of the ocean wall could actually be land with a zero movement sea unit camouflaged to look like the wall on it. Careful management of the coast images is needed in this case. This is a viable alternative to simply changing the terrain via an event as the player has to discover the weak section in the wall.

A third use of zero movement units involves revealing a specific location. You will need to use an air unit with double visibility. There is no need to make the unit appear like the terrain below it, you can just make it blank or invisible. An event will create the unit and reveal its surroundings. Thereafter, the invisible unit will crash. The story line has to be made consistent with an adjusted “plane ran out of fuel message” that will follow.

SAM Sites and SDI

Another thing to note is that the SAM battery doubles defense against all non-nuclear air attacks but not against sea or ground missiles and SDI doubles defense only against air missiles (and nukes of course).

AI Limitations

In all the instances above, I have assumed that there was a human brain behind any clever use of the combinations of abilities presented. It is usually advisable to give fancy units only to the human player while keeping the AI units pretty standard. While a human might figure out how to take advantage of non-conventional combinations of abilities, the AI will usually be confused by anything out of the ordinary. Sometime, like in the case of air-settlers, the AI works fine.

As a rule of thumb, what the stated role of the unit is, like naval superiority or diplomacy, will decide what the AI does. But that is not always true. For example, AI cruise missiles have a propensity for attacking ships (especially those with 4 hit points like battleships) and not land units even though its role is attack and not naval superiority. So I am quite that sure things like para-dropping ships onto land is AI unfriendly.

Studying how the AI “cheats” is important too. For example, an AI air unit doesn’t run out of fuel when you create them over a land-carrier using the cheat menu. I am told that AI triremes don’t sink or at least don’t sink as often as they are supposed to. When in doubt, AI testing (set human player to no human) and more testing is essential. I would really like to try the AI’s reaction to every possible combination but that would take a lifetime so the responsibility of ensuring AI compatibility of any units you create falls on you, the designer.


Any unit which has unusual features or which is meant to be used in a particular way requires extensive in-game documentation. A casual mention in the readme.txt might easily go unnoticed and many players might just brand the special unit as useless without a second thought. Ideally there should be a message via the events editor explaining the nuances of a new unit when the advance it requires is discovered. In any case, the civil-pedia should be updated at the least.