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[Sofaspud]

A caisson is an engineering device to let you work underwater without using scuba gear or dive suits.  For DF purposes, I suggest that they require Architecture, Masonry, and Mechanics to construct, and several stone blocks and a few wood logs, along with a Screw Pump to pump out the water after it's been built.

In usage, I imagine them as forming a rectangle, defined the same way that road sections or bridges are defined (and requiring more stone the larger they are); once they're built the screw pump must be built on top of/next to it so it can drain the water.  This will require careful placement so as not to flood the wrong things.  Once the water is pumped out, the caisson forms a 1-z-level-deep damp stone room.  They must be adjacent to solid ground to be built, since dwarves don't have good boats; if you were careful with placement, several caissons could be built edge-to-edge to make larger structures.

This could be used to reclaim portions of land from lakes or the ocean, and as a reliable way to penetrate an aquifer.  It would still require a good amount of work and effort, so I don't think it would make it too easy on aquifer maps.

During construction it could be sabotaged by monsters, resulting in a 'washout', which destroys the building and washes away the materials.  After construction, it'd be all to easy to 'accidentally' mine out a wall section, thereby unleashing the flood; this is probably bad, though I see potential here for traps, maybe.  You could build, say, a 5x5 caisson into an aquifer and pump the water out, then build a 1x5 wall along one edge with a floodgate in the middle linked to a lever, breach the caisson along that edge (hopefully without drowning your miner), and finally build a bridge over the whole thing.  Link the gate and the bridge to a lever and you've got a handy-dandy drowning pool that's filled by the aquifer itself.

[Tahin]

I support any way of making it possible to work underwater. This would work nicely, though the same effect could be achieved by allowing us to build underwater.

[ December 05, 2007: Message edited by: Tahin ]

[Grek]

Isn't this posible using rewalling and screw pumps?

[Sofaspud]

Re: rewalling and screw pumps

I suppose it IS possible in some cases, but not all.  For example, if I want to reclaim land from a huge lake, I need to drain the whole lake to do it, and they don't refill properly (during rain, for example).

Forget about reclaiming land from the ocean, I don't think you can get enough pumps in the same spot (could be wrong, but it didn't work so well last time I tried).

Breaching an aquifer is tricky at best with this.  Again, you have to cram a lot of pumping into a small space and work outwards.

IMO, a caisson-like device is (1) well within dwarven capabilities, and (2) convenient enough, yet challenging enough to use, that it would make a good inclusion into the game.

(In-game, think of it this way: you build a big square box, hollow in the inside, and drop it into the water.  Then pump it out.)

[Tahin]

If it's water-tight, there should be no reason to pump it out after dropping it in. Only if you built it in the water would you need to do this. However, you would need some sort of airlock which would then be pumped out, so it would require a pump. I don't see a specific object out of the build menu to be the solution, but instead more intelligent constructing, allowing you to build a "caisson" and drop it into the water without it breaking apart, probably with the use of chains and mechanisms. But it should be manual, not a specific building, otherwise a lot of freedom and feeling of accomplishment is lost.

[ December 06, 2007: Message edited by: Tahin ]

[Geofferic]

... GO ROLLING ALONG!!

[Dagonus]

quote:Originally posted by Geofferic:
<STRONG>... GO ROLLING ALONG!!</STRONG>

Wrong type of caisson.

I like the caisson idea though. Both types.... towing extra ammo and a limber for the ballista would be great....
Back on topic though, I don't think they should be "permanent" styled structures. It seems you're talking about using them for all sorts of expansions and I'd rather seem them being a way to get in, build a few walls, some floors, and a ceiling (God I'd love to build a ceiling instead of a floor for the level above...) and then remove the caisson from around it so that the caisson isn't made of "stone" in the same way a road or bridge is because that will lead to them acquiring permanent use instead of being a facilitator for permanent use facilities.  How to allow the transition to take place reasonably... I don't know.

[Gen. Lee Outrageous]

Bumping this because I seriously crave some deep water engineering.

Though granted caissons themselves probably do not satisfy the cutoff date, an "open box" caisson could be made by using pilings as guides to drop in stone blocks forming a levee (the use of which dates back over 5 thousand years, though not necessarily by the method I described, and as for pilings the use of those goes back to roman times).

If boats are ever implemented this could allow for mid-ocean forts to be built. Which I think would be all sorts of fun, and also provide ample opportunity for the other kind of fun.

[Soralin]

You can sort of do this already, although it could be made easier with some additions to the game.

Currently, you can make and drop obsidian blocks to form a wall around some area, then you can use a screw pump to pump out the top layer of water, and then build another on the layer below to pump out that layer, with the aid of the top pump, and so on and so forth, and eventually you could empty the water out of the area.

One thing that would make it much easier to do, would simply be the ability to drop walls into positions, and have them remain intact.  Since it's difficult to have to create obsidian walls on the spot directly where they're needed, if you could just construct the walls like you would any other, it would be much easier to deal with.  Additionally, something like a pipe, or extended screw pump, something that you can drop down, to pump water from more than one level deep, would mean that you could move more than just one level of water down at a time.

[NW_Kohaku]

Wow, 2007...  This was JUST after 3d was introduced...

Anyway, I think something like this could potentially be possible (I think Romans had underwater cement, didn't they?  We could create a way to drop cement that hardens into walls), and essentially be a "build wall down".

Of course, currently, provided you have some place to actually put it, screw pumps are so much faster than water flows that you could technically just pump water out at the same rate that it comes in, and build those caisson walls in the dry space you create.

[Lord Darkstar]

The problem is if you are desiring to do DEEP WATER construction. 1 z level, pumps work very well, but 3 z levels or 5 z levels?

Caissons themselves are just 4 walls and a ceiling. Dwarves can build that right now. But they lack any of the DEPLOYMENT methods that we humans use. For instance--- build an open bottom box out of wood. Float it in the water. Barge it to desired spot. Tie ropes/chains to it to control its about to begin sinking--- and sink it by opening hatch(es). Once in place, repeat with more boxes on top until you have constructed a "temporary" building underwater. Now, pump the water out, seal any leaks, and work your way down as desired. Now you can mine the floor, or fill it to make a permanent footer for a bridge, or whatever else you want. Without boats/barges and controlled sinking, this just isn't going to be doable.

The other way to do water construction is to sink walls or pilings until you create a coffer dam. Then you pump out the water and do whatever you want in that space. If we could just drive/drop pilings, we could at least do coffer dams. We don't even need boats--- as dwarves could just construct floors out to where you want to work (just go 1 z-level up first, and be "above" the water). Then get to your desired area, and start building a pillar or pipe down. If it requires a couple of mechanisms, so you only build on the end in the air, and then extend it down 1 z-level, that would be cool by me. Once you get your pillar to the floor, you move to the next spot over and repeat. Continue that until you've enclosed your desired work space, and you have a coffer dam. Pump out the water, build what you want, have fun. Just look out for all the FUN that could happen (ie, a water titan swims up, knocks a hole in your coffer dam, gets into your filling space, and has FUN with your dwarves. A flying or jumping or amphibious megabeast of some sort comes down and has FUN with your project--- ambushes from aquatic mud dwellers attack you, etc etc etc.

Frankly, I was very surprised when playing DF and found out I COULDN'T make coffer dams. Seems like a major and basic constuction is missing in an otherwise well detailed base construction system. I understand we will get some capacity to build down into water at some point, but I wonder if it will happen in this upcoming "top 10 user requests" coming up.

[Geb]

Having dwarfs use a very primitive sort of caisson, just an open topped wooden box as far as the bit in the water goes, would be more appropriate for the scale of the game. Having an in game version be crude and leaky would be a good way to emphasise that it's supposed to be a temporary structure. Let water fall into the dry space occasionally, just fast enough that you can't rely on evaporation to take care of it. The bigger and more watertight types are better represented by normal constructed walls, I think.

I'm imagining it being a bit like the game's bridges, something that must be built on the edge of water, a structure that can be raised and lowered at the pull of a lever. The structure as you build it in game would be a combination of watertight box, crane, counterweight, pulley... This way it could be removed and dismantled once the underwater work was done without leaving all the components stuck underwater.

[Lord Shonus]

It's amazing that a post from so far back can still be an incredibly logical suggestion.

[NW_Kohaku]

It's amazing that a post from so far back can still be an incredibly logical suggestion.

The sarcastic side of me just begs to say, "Yeah, because people were all total idiots way back in 2007! Who would have thought there would be a good idea from that year?!"

Having dwarfs use a very primitive sort of caisson, just an open topped wooden box as far as the bit in the water goes, would be more appropriate for the scale of the game. Having an in game version be crude and leaky would be a good way to emphasise that it's supposed to be a temporary structure. Let water fall into the dry space occasionally, just fast enough that you can't rely on evaporation to take care of it. The bigger and more watertight types are better represented by normal constructed walls, I think.

I'm imagining it being a bit like the game's bridges, something that must be built on the edge of water, a structure that can be raised and lowered at the pull of a lever. The structure as you build it in game would be a combination of watertight box, crane, counterweight, pulley... This way it could be removed and dismantled once the underwater work was done without leaving all the components stuck underwater.

Well, the problem is that the way that this should work is that the box would just keep the water out long enough to build a serious wall... which means you need a box bigger than the wall you will build.

Honestly, I think the best way to handle this is to somehow have a means of just plain dropping stones into the water until you make a leaky temporary wall, which you can dump until you completely surround a worksite, which you can then dig down and build pumps further and further down until you can completely drain the area (which would get nice and progressively more complex the deeper the water you are doing this in), and build the "real walls".

The problem would be removing the temporary wall from outside the finished wall once you were done.

[Lord Shonus]

It's amazing that a post from so far back can still be an incredibly logical suggestion.

The sarcastic side of me just begs to say, "Yeah, because people were all total idiots way back in 2007! Who would have thought there would be a good idea from that year?!"

You know what I meant. The game's changed so much that you wouldn't expect such an old suggestion to be still fully relevant.