Pics of Pacifica, New Pacifica City and Deep Trench Outpost: http://tinyurl.com/pw68b59

With the advent of SMP I've played many different servers, all with factions mod and in them all I experimented with different designs for underwater living structures. What is the smallest, most utilitarian structure that is nonetheless self sufficient? How big does it need to be in order to not feel cramped to people accustomed to life on land? What's the most efficient order of module construction? What's the best design for the initial workshop module that you expand from? My first experience with a large crew living full time underwater was back on my Deep Trench Outpost, but that used mcedited seafloor ore deposits so it could be built from iron. It was also an extravagant design only possible because of the abundance of resources.

More recent experiments, Pacifica City and New Pacifica City, were my second experience in having large numbers of people accustomed to living on land living instead fulltime in a manmade underwater structure. It was interesting to see how they used it, how they expanded on it and furnished their dwellings. I learned things like the need for larger apartments (as people expanded their own otherwise) and that sand can easily be sourced from the seafloor using respiration 3 helmets. This eliminates the last resource it was necessary to continually get from land, making it possible to endlessly expand colonies without ever surfacing. It was also built 100% legit, on a server where you're under constant threat of attack by other factions.

After gathering about 4 stacks of 64 stone brick, glass, seeds of every type you can get ahold of, tree saplings, bread, tools, wood, a chest, bed, furnace, workbench and doors (for breathing) you can go into the ocean, scout a nice deep flat spot for your colony, and build the following:

1. Initial 5x5 work shelter (octagon shaped, with two 3 block farms, a bed, a chest, three stacked ovens and a workbench. 1x1 hole in the floor allows entry and exit. You can now grow food and smelt minerals on site as well as sleep. Basic livability, ability to skip nights, storage and crafting/smelting capability. As a note going forward, all structures should be up off of the seafloor on 'stilts'. This prevents people from burrowing down to expand underground because they don't like underwater construction, and it prevents a method of blasting upward to gain unathorized entrance into the colony. It also avoids issues with uneven terrain that would normally require you to go outside and level the terrain or build awkward tunnels that go up or down a level to follow the terrain's contours. If the structure is elevated two or three blocks, there's space for moon pools underneath (only advisable in singleplayer) and everything can be built on the same level.

2. Mining module (Second 5x5 standard module connected to the first by short tunnel, with a mineshaft going down into the sea bed. You can now source minerals locally, making it possible to begin expanding using in situ materials instead of the finite supply you brought from land.

3. Agricultural dome. 5 frequency (longest sides are 5 units long) dome tall enough to grow trees, with dirt blocks around the interior rim for growing edible crops. If you brought enough materials from land, you can optionally skip step 2. and after the agricultural dome is done, just repurpose the work shelter into a mining module.

4. Livestock module. You want them to have their own space so you're not tripping over animals while trying to chop down trees or having them trample your crops. This should be very big. Mine are usually pill shaped. Only legit way I know of to get cows, sheep, pigs etc. inside is to build a 3x3 glass tube from the roof of the module all the way up to the surface, then lure cows from the nearest landmass using wheat so that they fall down the tube. Seal the roof, flood the tube using a bucket, then destroy the tube. This is after you have two of every type of animal you want inside. To get grass down there you'll need to enchant a silk touch pick so you can gather grassy dirt blocks. You might consider a second livestock module exclusively for sheep: If you can mass produce wool, it makes the process of purging water from a newly constructed module much, much easier as you can fill it with wool, then burn it away. You can do this with wood but wood doesn't burn completely and leaves behind a mess of unburnt blocks. Wool is ideal and once you have enough sheep to produce wool at a rapid enough rate you'll feel a lot less reluctant to start work on big new modules as you'll have eliminated one of the most work-intensive parts of the process.

5. Living quarters. This is #5 and not #1 or #2 because there's no point to bringing in more mouths to feed, so to speak, until you have the four modules listed above completed. They'll need those self sufficient resources in order to accomplish anything productive, and to meet their own needs. I recommend three story structures, each floor 3-4 units tall inside, with the apartments around the outer edge so every one can have a window. This makes more efficient use of materials since they share a lot of walls/ceilings/floors.

6. Warehouse module. You will accumulate loads of resources of all kinds. Make sure all chests are labelled by content and that people are disciplined in sorting items into the correct chests. It's important to be able to find the materials and items you need when you need them.

Laboratory. Small module, just needs an enchanting table and potion brewing setup plus chests for ingredients and finished potions.

7. Automation. Mob grinders, autofarms, that sort of thing. Most people are too lazy to manually farm and will just consume prepared foods until it's empty, then complain or make themselves bread or kill a livestock animal. To keep everyone happy with a minimum of labor on your part or theirs you will eventually want to automate the production of food and of as many types of loot drops as possible. This also provides a free source of goods you can trade for other goods or money (for claiming more land) in factions servers.

As exhausting as all of this sounds, if you've done all of it, you've completed the barebones comfortable living provisions for an underwater population. All of this stuff is required to provide the same amenities they're used to on land, which is necessary to persuade the average person to live full time in an enclosed structure deep underwater. Some will come just to gawk, then leave. Some will live there for a while but then leave. The ones who remain behind are your core crew. Labor should be divided accordingly:

1. Sand miner. Full time job, you'll need lots of glass. They will need an aqua affinity diamond shovel and a Respiration III helmet, as well as a bucket (for emergency breathing) and doors (as temporary air shelters). Their job entails walking along the bottom, placing doors near large seafloor sand deposits, then gathering all of the sand in that patch. Then picking up the door, moving on to the next patch and repeating, till their inventory is filled with stacks of sand. A compass is highly recommended so that they can find their way back to the colony.

2. Farmer. Neither breeding livestock nor harvesting/planting crops is a fulltime job by itself. But if you combine the two and add in chopping down and replanting trees it's enough to keep one person fairly busy. A lot of their duties will eventually be automated. If on a factions server, you can also assign farmers to dig squid traps outside and use a respiration III helmet to occasionally go out and slaughter the squids trapped in them. This provides loads of ink sacs for dye, something people who live on land don't normally have the occasion to gather themselves. If you scale up this operation, ink sacs can become your primary export. If you go this route you might consider building a mini-colony elsewhere surrounded by squid traps, as a dedicated squid farming operation.

3. Miner. Loads of people will want to do this, which is fine. The important thing is to provide them a large, well equipped mining module with many banks of ovens and storage chests. If you don't provide this, they will begin to expand underground even if told not to; This is an underwater colony, not underground.

4. Construction. Quickly discover who is skilled at building underwater and make them the only crew members authorized to build new modules. It is an exhausting job and only a certain type of person has the patience for it. If you let just anyone do it, your colony will become an ugly cluster­, with some well designed nice looking parts and others that are clumsy dirt and glass boxes. People should carefully plan what gets built where so there's no overlap or claiming space other people planned to use. In New Pacifica City I built a central corridor with offshoot corridors, to guide people as to where to expand. This type of shared corridor space is a good idea as it creates more of a sense of open space than lots of clustered buildings with only short tunnels between them. Main corridors should be 5x5 wide/tall. Offshoot corridors that connect the main corridor to modules should be 3x3. This turned out to be what was required so people didn't get claustrophobic.

5. Redstone engineer. You will need at least one. Doing redstone machinery underwater is a huge pain in the ass as redstone machines are very large and accordingly need some of the largest modules. Have them plan it out first and come up with a design that is as compact as possible, so you know exactly what dimensions the module will need to be.

6. Soldier. If you intend to raid other factions you'll want to leave that to those who are best and most experienced at combat. They will typically not want to help with anything else and that's fine, they more than pull their weight as a deterrent to anyone who would raid you and by bringing back loot. Keep them well supplied with splash damage, invisibility, speed and other combat relevant potions using the lab module.

7. Alchemist. Possible side-job. His role is to go around gathering the necessary ingredients for potions and to use a spider grinder or end grinder to gain the levels needed to enchant books, which can then be used by others to enchant items as needed. This is a fairly tedious, thankless job except for the "adventuring through the nether to find ingredients" part so generally out of a large crew only one guy will be eager to do it.

To clarify, jobs are not forcibly assigned, but chosen. I found that certain people have obsessive interest in performing specific tasks and it's best to have clear, delineated roles so everybody knows what they're supposed to be doing without anybody presuming to be the leader. Basically "Do what you want, but when you have time to kill and feel like helping out, do this since it's something you enjoy anyway." This makes sure that everything that needs doing gets done instead of 75% of people choosing to mine all the time with one or zero farmers/construction guys, or any similar situation with an unbalanced division of labor.

So, why build underwater in the first place? Why do I always do that? In Factions servers I've discovered it's the best of a limited set of options if you want to be safe from raids/griefing. Most will not have enough need for a respiration helmet to use up 30 levels enchanting one, so putting your colony as far underwater as possible makes it a danger and a hassle for them to swim down to it. TNT does not damage blocks when it's in water (building an underwater tnt cannon is a nightmare anyway) and there are no creepers to herd near your structure, another popular method for damaging claimed land. You can cover your land base in water but this looks ugly and stupid, whereas an underwater city is cool to look at and makes sense. You can live deep underground far from spawn, but you're permanently cooped up and surrounded by dirt, rock and darkness. Underwater there's a great view. The sun and moon are visible. You can tell when it's day or night. You can exit your colony and walk around freely outside on the bottom in relative safety; Whereas exiting your base on land means you're vulnerable to enemy faction members laying in wait, deep underwater you can look up to see anyone lingering on the surface, and they are not likely to risk drowning to swim down and try to engage you on the ocean floor.

I do not recommend using moon pools for entry on a factions server. If they can get into a dry space and are using exploits that let them place and detonate TNT, in a dry space it will cause damage. Instead use a redstone airlock; Other exploits or server settings might let them open doors/hatches, but a redstone airlock will be impassable to them. Iron doors with buttons only on the inside are another option. If you go either route, you'll want to equip seafloor sand miners with the resources needed to build their own little 5x5 work shelters on site so that if nobody's online to let them in they have someplace dry to sleep, store their gathered sand, smelt it and grow food.

Above all else, expand on a regular schedule. There should be a new module every week. This gives the colonists a consistent, exciting sense of growth. If you don't do this their urge to explore new places will drive many to leave the colony and return to land. Regular, rapid expansion satiates that need, keeping them logging in and working to see the next expansion and how big the city will ultimately get. To this end you should also encourage the construction guys to go build their own mini colonies nearby, far enough away that the two won't compete for land but close enough that it's a tolerable distance to walk along the bottom using a resp. III helmet, as boat travel between them is unsafe on a factions server. Creating multiple destinations to visit, especially if made from different materials (Pacifica was made from sandstone and featured very different architecture from New Pacifica City) will give people variety, and places to travel to and from, which also gets them outside so they don't feel cooped up. This will also make noobs more comfortable with EVAs (activity outside the colony in the open ocean) which will help them learn to safely build their own expansion modules or mini-colonies elsewhere.