The "blockade" mission?

[onomastikon]

I'm at work with no access to the CivPed, and cannot find the info on this site, hence my question here, about which I am confused:
- I think it is called the "blockade" mission: the little icon that looks like a cannon which ships can perform in foreign waters. If it is called differently, please let me know.
- Do I understand correctly that this mission has two components? One of which I find is well documented (or I remember it being so), and one of which *really* confuses me.
1. Component 1 seems to be blocking trade routes to the city within the boundaries of the blockade mission. Here, my confusion results merely in (a) the scope and (b) exactly what "trade" is meant here.
1a. Do all ships have the same "block" radius within which trade is blocked? Some seem to be long and thin, some wider. How much area near a coastal city needs to be within this scope for trade to be blocked? Must sometimes 2 or more ships use the mission to fully block a city? How can I tell when a city is blocked?
1b. What exactly is blocked? Does "trade" mean foreign trade routes (those little +x coins you see in the top left of your city screen) via water? Or all trade? If it means foreign trade via water, it seems that this mission isn't exceptionally harmful, but perhaps I am missing something.
Does it also exclude a city from trading resources if that city has no other trade route available (e.g. an island)?

2. Component 2 I have seen only once, yesterday, and it puzzles me. In a war with Asoka, who was getting his tuchus handed to him on land but who had outteched me vastly and hence had destroyers when my strongest ship was still a frigate, did little but have his destroyers lower the defenses of my cities (which he was never able to reach with land units, ever) to 0% while I decimated his cities with rifles, cannons and cavalry. While he was doing this, I noticed what I normally notice: one square in my coastal waters has a little red circle in it representing an enemy unit, and this square cannot be worked. No surprises there. But at one point, I think he must have chosen the "blockade" mission, but I am unsure (I believe I had mercantilism on, as I almost always do the entire game, so am unsure how this affected trade routes, if at all). What made me go "hey!?!?" was that I believe I could see a grayed-out area in front of my coast (which I believe I can see in front of foreign coasts when I use the mission, which is rarely) and -- this is the key -- when I clicked on my city, *ALL of the squares* of its coast were unworked and I had a bunch of specialists when before I had only 1 (from mercantilism).
In other words, does component 2 mean that a city cannot work coastal or ocean squares being blockaded by a blockade mission? If so, I didnt know that, and this seems like a reason to actually use the mission. Up till now, I had positioned my boats on enemy coastal resources and fortified, and had backups on other squares to place those "red circles" in their BFC. But if this is actually a component of the "blockade" mission, then I could use those extra transports I always seem to have to spam these missions and starve the snot out of my enemy?

Follow up question would be: If this is the case, why doesnt the AI use it? So far, I have seen it used it ONCE. I just finished a game as the Dutch (way overpowered -- it's like a free Maori Statues in nearly every I had city!), and using the blockade would have crippled me vastly!

 

[RIcs]

I notice the blockade also means the city can't work on the blockaded tile.
Blockaded tile always just 3 square from the unit. (even on the other side of the coast... but doesn't work on in-land sea or lake.) same for frigate, destroyer, cruisers...

Trade routes, i think you need to block every port it has.. otherwise it can detour !?!

 

[GIO888]

Blockade blocks every square that vessel influences - soz, don't know the differences between vessels however.

Blockade an Isthmus or other choke point, trade has to go around it, so if the AI don't have open borders with each other you can really put their $ a Barrel prices up!

I routinely use several Privateers to blockade my closest rivals - really affects the Fin Civ's too.

 

[Bushface]

The blockade range is a 7x7 tile square with the blockading ship (any warship) in the centre. This area shows up (if you select a blockading ship) with a border in your civ's colour and some fainter diagonal lines. If you're American, these markings are extremely difficult to see ! Blockading affects only sea tiles, which the blockaded civ then cannot work. A blockading ship gives you gold every turn, usually 2 or 3; I once managed 62 blockading privateers, which boosted income very usefully until my foes began to make frigates: also, a blockading privateer sends the enemy AI into a frenzy of building triremes and/or caravels, wasting production and giving you lots of near-free GG points.

 

[PieceOfMind]

Well the only time you get gold per turn for blockading is if you're using a privateer. In all other cases you must be at war with the civ and inside their borders and the blockade works like the OP described.

I find that blockading is mainly useful to hurt the coastal cities, making them starve. Sometimes if I plan to invade soon anyway I won't bother pillaging their fishing boats but I do like to prevent them from using them!

It's pretty hard to know the exact details about how trade routes are affected but I think this is how it works (this should be checked with someone else though)...
Basically if the area you are blockading (and non-blockading ships count as blockading the single tile they're on AFAIK) includes all the water tiles adjacent to a city then that city will not have any coastal trade routes. It's probably also possible to blockade a city's coastal trade routes without getting every adjacent square but this would be pretty uncommon. See trade routes are calculated every turn and they must have an actual path. If there is no path (which is very obvious if all the surrounding water tiles are blocked) then there are no (coastal) trade routes.

If you manage to blockade all the coastal cities on a landmass I'd imagine you exclude every city (including inland cities) on that landmass from having trade routes across water.

I just had an idea too (probably not new to anyone here) but if you bring a few privateers along with your normal fleet when you are attacking an enemy, not only could you blockade their trade routes but you could also plunder them. You could protect your privateers with your own ships, but you'd have to be careful that there are no rival ships hanging around that are at peace since they could attack your privateers.

 

[frekk]

I just had an idea too (probably not new to anyone here) but if you bring a few privateers along with your normal fleet when you are attacking an enemy, not only could you blockade their trade routes but you could also plunder them. You could protect your privateers with your own ships, but you'd have to be careful that there are no rival ships hanging around that are at peace since they could attack your privateers.

Theres no point in blockading an enemy with privateers when you're at war (unless privateers are your best fighting ship). They do not generate gold per turn unless you're blockading someone you're at peace with. So you might as well use frigates or excess galleons you have no use for; save your privateers for blockading people you're not at war with.

 

[PieceOfMind]

Theres no point in blockading an enemy with privateers when you're at war (unless privateers are your best fighting ship). They do not generate gold per turn unless you're blockading someone you're at peace with. So you might as well use frigates or excess galleons you have no use for; save your privateers for blockading people you're not at war with.

Oh ok. Come to think of it I'm sure I've tried it before a long time ago and realised it didn't work. I'd just forgotten.
Ignore that idea then.