Port blockading - is it possible?

[Martinus]

I seem to remember reading somewhere about it, but cannot find it in the manual - is it possible to effectively blockade another civilization's port?

What I mean by that is this: assume for simplicity that a civilization which I'm at war with has only one port on a given continent - is it possible to place my ships around the port (e.g. on all sea squares surrounding the city) that will effectively cut off any trade network it may have with other continents?

[johnmcd]

Maybe, and I don't think it would need to be all squares. I think ships interdict all squares around them too so a one tile island would only need four boats around it to prevent it working all squares. I don't know if trade works differently though.

It's about the only example of a zone of control in the game that I can think of. Again, it may not work quite as I've described it, but it's certainly in there.

[Strategist83]

I highly doubt blockading is possible but I wish it were. Expansion/patch material.

[MattPilot]

In Civ3 ya could - haven't really tested it in Civ4, but i'm thinking, why not?

Doubt the trade commerce is affected though.

[Hotnails]

I tried a blockade recently, lost several ships in my effort.

[Blake]

I THINK ships have an all-adjacant tiles zone of control, preventing all tile working and possible trade routes in that water. I know for sure it works at stoping workers but only speculate that it stops trade. The tricky part is there is so much damn ocean that trade routes would usually find another way around.

Take the example of a civ on a continent with only one port city, it could possibly have the following ways out:
Via river, either a city founded on the river or a road connecting to the river.
Via road to an ally on the continent, the allys port cities and rivers can be used.

I'd say that the chacne of being able to cheaply blockade is 1 in a million - I mean, cheaper to blockade them than just conquer them. Assuming blockading even works.

[MattPilot]

I guess worldbuilder could be used to make a test.

Set up enemy ships all around your island and see what effect it has on trade etc...

[Fried-Psitalon]

Yes, it's possible.

[MattPilot]

does one ship have to be on each square, or do the adjacent squares also get blocked.

I know it applies to city workers, but i'm more wondering about blockading trade.

[Martinus]

Also, does it work only for blockading cities, or can you blockade anywhere along the coast if the geography allows you to do that?

For example, on a map of Europe, could you put a ship or ships on the Gibraltar straits and effectively cut off any trade network between the Mediterranean and the North of Europe (assuming there is no land network)?

[johnmcd]

Anywhere along the coast I believe. I've had early trade routes cut by a barbarian town popping up and claiming the coast, ie, you couldn't sail a galley past the town without going through 'its' waters.

[Vynd]

I've had cities blockaded by AI ships. One instance that I recall well was where I had a coastal city that had water to its west, SW, and south and land everywhere else around it. The enemy ship sat directly to my city's SW and I wasn't able to work any water tiles. This resulted in massive starvation since the surrouding land was mostly desert. That would fit with the 1 space zone of control theory. The enemy controled the space it was on and the space north and east of it, leaving me with no exit from ym city. I can't recall if the blockade affected my trade routes. The city was connected to the rest of my empire via road so it probably didn't do anything.

I could be wrong, but I think the AI ship sat next to my city for awhile even after it had finished bombarding my defenses to zero. Meaning that the AI was deliberately and knowledgably blockading me, which is pretty cool.

There are other examples of zones of control. Some units can intercept enemy aircraft if they fly next to them, for example. Siege units can tell when they're next to a city and offer the bombard command as a result, which is kind of like a zone of control.