Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Ter13]

My current fortress is on a volcano jutting out of the ocean. I would like to make a glass dome under the water at some point, but have no idea how to go about it.

Currently, I think the only problem I'm having is how to safely remove the obsidian dam this project will require

I plan on casting the edge of the ocean with lava hauled up from !!CANDYLAND!!. But there are two problems here, first, I can't remove the walls safely because pressure will cause the water to rise faster than I can work, and second, it will leave a metric fuckton of obsidian to be stuck at the bottom of the ocean.

Perhaps a more novel approach of mining out a cavern underground at the edge of the map, with the ceiling of the cavern hollow. then I line the bottom with dwarven atom smashers. Set on a repeating sequence using water/pump alternation on pressure plates. The next step is to make a suspended ring of constructions to drop into the chasm. This will begin filling with water rapidly, and the atom smashers should begin their work.

I had thought of another method involving 3x3 spires of cast obsidian hollowed out with bridges, then using lignite in bins to evaporate the ocean, but I am not so sure this method would work at all.

Does anybody have any suggestions for draining an ocean temporarily with minimal wasted material left at the bottom, and acceptable unskilled labor losses?

[Corai]

Dig to all caverns, let the circus go, break the top caver. Flood everything (and your miner)

[malroth]

vampire miner doesn't care if he accidently covers himself with 20z levels of water

[Girlinhat]

Check my sig and look for Sphalerite's sea serpent and/or mermaid farming.  There's some very good ocean-draining methods already documented.

Essentially you need a drainage tunnel, and punch a hole in the roof of the tunnel.  An ocean is just a large river.

[Sphalerite]

Dig a large, wide tunnel directly under the ocean.  Dig it all the way to the edge of the map.  You won't be able to dig out the last line of tiles at the map edge.  Instead, smooth them, and then carve fortifications.

Build a raising drawbridge one tile deep, and as wide as your drainage tunnel, right next to the fortifications.  Link it to a lever somewhere safe.  The bridge should completely seal off the fortifications when raised.

Now build a platform above the ocean, over the drainage tunnel.  Collapse it, either using a remote-activated support, or a sacrificial deconstruction dwarf.

If you have done it right, this will punch through the ocean floor into your drainage tunnel.  The ocean will then begin drain through the tunnel out into the map-edge fortifications.

Now build your dome.  Watch your dwarves build in slow-motion, as all the moving water kills your FPS.

Once you are done with construction, pull the lever to raise the bridge and seal the drain.  The ocean will now refill.

[Astramancer]

I've also seen a massive, massive sequential pump ring doing the moses effect to build on the bottom of the ocean.  That's far more dwarfly.

[Ter13]

Okay, I think I just figured out what I'm going to do. I am going with a combination of edge-draining and obsidian damming. First, I cast the edges in obsidian, and carve a drain under the retaining wall, punching it open with a collapsing construction. This drains the inside of the cast. Then, when I am done with the construction, I channel a hole beneath the retaining wall and collapse it out of the way using supports. I can do this one layer at a time, or I can do it all at once.

Either way, this method will generate no excess materials on the sea floor after I am done, will only drop my fps while draining the ocean, but make building be regular speed, and nobody HAS to die to make it work.

[zilpin]

Okay, I think I just figured out what I'm going to do. I am going with a combination of edge-draining and obsidian damming. First, I cast the edges in obsidian, and carve a drain under the retaining wall, punching it open with a collapsing construction. This drains the inside of the cast. Then, when I am done with the construction, I channel a hole beneath the retaining wall and collapse it out of the way using supports. I can do this one layer at a time, or I can do it all at once.

Either way, this method will generate no excess materials on the sea floor after I am done, will only drop my fps while draining the ocean, but make building be regular speed, and nobody HAS to die to make it work.

Brilliant!
Report back on progress.
Fun shall ensue.

Zero-deaths is the ultimate DF challenge.

[Sphalerite]

Take screenshots and post them.  Especially ifwhen it goes horribly wrong.

[Urist Da Vinci]

1. Build a magmaduct and platform above the ocean.
2. Cast hollow rectangular walls of obsidian and drop them to the (flat) ocean floor.
3. Once hollow space reaches surface, drain the interior.
3b. Deconstruct most of the sky platform if desired (see step 7).
4. Build arbitrary watertight structure on ocean floor inside the caisson wall.
4b. Build an ocean-floor city with glass windows that could be broken during tantrum spirals.
5. Dig under your obsidian caisson wall so it is only supported by floor tiles on the outside.
6. Channel under your obsidian caisson wall to an equal depth of the height of the wall.
7. Drop a constructed ring from the sky platform to pierce the ocean floor on the outside of the obsidian caisson wall.
8. The obsidian caisson wall is now unsupported and caves in to become flush with the ocean floor.
8b. "Hide" any annoying boulders which may be sitting on the ocean floor.
9. A massive wall of water pours in and covers the hollow space, restoring the original ocean.

10. Turn on the fortress economy in your ocean-floor fort, give the fortress guard/hammerer bronze helmets and spears, and don't meet any of your mayor's demands.


FYI I did this in 40d.

http://en.wikipedia.org/wiki/Caisson_(engineering)

[Ter13]

1. Build a magmaduct and platform above the ocean.
2. Cast hollow rectangular walls of obsidian and drop them to the (flat) ocean floor.
3. Once hollow space reaches surface, drain the interior.
3b. Deconstruct most of the sky platform if desired (see step 7).
4. Build arbitrary watertight structure on ocean floor inside the caisson wall.
4b. Build an ocean-floor city with glass windows that could be broken during tantrum spirals.
5. Dig under your obsidian caisson wall so it is only supported by floor tiles on the outside.
6. Channel under your obsidian caisson wall to an equal depth of the height of the wall.
7. Drop a constructed ring from the sky platform to pierce the ocean floor on the outside of the obsidian caisson wall.
8. The obsidian caisson wall is now unsupported and caves in to become flush with the ocean floor.
8b. "Hide" any annoying boulders which may be sitting on the ocean floor.
9. A massive wall of water pours in and covers the hollow space, restoring the original ocean.

10. Turn on the fortress economy in your ocean-floor fort, give the fortress guard/hammerer bronze helmets and spears, and don't meet any of your mayor's demands.


FYI I did this in 40d.

http://en.wikipedia.org/wiki/Caisson_(engineering)

Yeah, had just figured this out prior to your post. I'm trying to do it without generating ANY excess materials on the sea floor, though. We'll see how that works out. I am going to have to use pumps to generate the caisson, that way the excess stuff from collapsing it won't go past the edges of the caisson. It won't be easy, but it should work.

[Ter13]

First simulation blueprint ended in utter failure. Second blueprint is on the way. I am attempting to use magma to encase and eliminate the excess materials generated at the sea floor. I drop the constructions into a layer of 7/7 magma beneath the surface of the ocean. It punches through and the water should flood down to fill the hole, which will cause the magma to turn into obsidian, resealing the hole and also encasing and destroying the excess materials.

If dwarf physics operate accordingly, this should be the ultimate way to drain an ocean, and efficiently manage the excess materials.

[Andrakon]

Well I just drained the ocean on two different maps and casted the base of a structure with magma in one of them so I can contribute my findings.

The easiest way to drain the ocean is to channel a 1 or 2 wide strip as long as you want, one layer below the ocean. Cover the channel in a retracting bridge or bridges and link them to a lever. Seal off that top level entirely. The next zlevel below either connect it to a strip of aquifers or tunnel it to the map edge, make it as wide as your strip is long. At the map edge you will have to smooth the last square and turn it into a fortification so water can flow through it. The last step is to designate ramps to be built along one or both sides of your bridge. If the zlevel the bridge is on is sealed, there are ramps directly under the bridge, and if there is a wall 1 zlevel below the ramps you are designating, your miners will stand under the bridge and dig all the ramps. This will create a hole in the bottom of the ocean onto the top of your bridges and your miners will mine out all of these ramps even if they are underwater now. So all you have to do next is clear the area, seal it off and pull the lever.

Now the problem I have had is I can drain all the layers of ocean except the bottom one usually. It will often stay full at 7/7 because I did not have enough drainage. If you want to have a dry spot you would have to have a strip of this completely surrounding your work area.


Now for the casting idea. I casted a large wall to be used for an entire base in 4 zlevels of ocean. What I did was drop a large square of lava onto the ocean all at once and repeat until it was at the top of the ocean. This of course forms obsidian and it falls to the ocean floor creating a nice walled off area that is easier to drain. Its a nice idea but in practice it has some major problems. What happened is even with savescumming and retrying the pour I always had a couple holes in the bottom, several holes in the next level up, and half of my 3rd level stabelized on the 4th. So it was completely full of holes. I tried pouring just so I wouldn't have to drain the ocean, but I had to anyway to fill all the holes.

Filling the bottom levels holes were nearly impossible due to such a deep ocean trying to refill from several z-levels of ocean edge. I didn't have enough drainage and should have surrounded my base with drainage passages. Doing this with a shallow ocean would be much easier. Of course one way around the bad casting job is to cast your basement before you drop it into the ocean. I haven't tried that yet, and probably won't any time soon.

[Ter13]

Yeah, I think pre-casting is the only way to go. Unfortunately, with my current design, pre-casting is not really an option. Have you figured out what is causing the holes?

[Sphalerite]

Fluids don't fall as contiguous blocks.  When you drop a large mass of magma, some of the tiles fall before others.  There is a pseudorandom order to determining which tiles of liquid fall on which ticks.  This causes some of the blocks of obsidian to form before others, which can then cause the resulting obsidian layer to be uneven.