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[bumblepuppy]

Hi all,

I read Urist Da Vinci's excellent design for a magmaless, pumpless freezing trap (link here), and I think I have a tweak to enhance it. The post is fairly old so I'm making a new topic on it.

Here is the original design:

Code: [Select]

     z+2         z+1         z0          z-1       
                               
 _ . . . _   w . . . w   w _ _ _ w             
 _ . . . _   w . . . w   w _ _ _ w     w w w w w   
 _ . _ f _   w . w . w   w _ G _ w     w H D _ w   
 _ . . . _   w . . . w   w _ _ _ w     w w w _ w   
 _ . . . _   w . . . w   w _ _ _ w     w w w _ w   
 _ . _ f _   w . w . w   w _ G _ w     w H D _ w w w w
 _ . . . _   w . . . w   w _ _ _ w     w w w _ _ _ _ _
 _ . . . _   w . . . w   w _ _ _ w     w w w _ w w w w
 _ . _ f _   w . w . w   w _ G _ w     w H D _ w   
 _ . . . _   w . . . w   w _ _ _ w     w w w _ w   
 _ . . . _   w . . . w   w _ _ _ w     w w w _ w   
 _ . _ f _   w . w . w   w _ G _ w     w H D _ w   
 _ . . . _   w . . . w   w _ _ _ w     w w w w w   
 _ . . . _   w . . . w   w _ _ _ w             
                               
 w  natural rock wall                             
 f  constructed floor                             
 .  open space                             
 _  natural floor                             
 G  grate                             
 H  floor hatch (hooked up to drain lever)                             
 D  door (hooked up to flood lever)     

Explained briefly, a water supply is stored above level z0 and is allowed to enter z-1. When the doors open, water rushes up and through the grate. As the surrounding squares are exposed outside, they will freeze. The hatches are used to stop the trap and allow resetting through mining the ice away.

Urist Da Vinci notes that enemies standing on the grate will not be frozen because the natural rock ceiling above prevents freezing, which is fashioned that way to allow the water to spill out in adjacent squares.

This is my proposal to overcome that shortcoming:

Code: [Select]

      z+2              z+1             z0        z-1       
                               
 _ . . . . . _   w . . . . . w   w _ _ _ _ _ w             
 _ . _ _ _ . _   w . w w w . w   w _ F F F _ w     w w w w w   
 _ . _ _ _ f _   w . w w w . w   w _ F G F _ w     w H D _ w   
 _ . _ _ _ . _   w . w w w . w   w _ F F F _ w     w w w _ w   
 _ . . . . . _   w . . . . . w   w _ _ _ _ _ w     w w w _ w   
 _ . . . . . _   w . . . . . w   w _ _ _ _ _ w     w w w _ w     
 _ . _ _ _ . _   w . w w w . w   w _ F F F _ w     w w w _ w   
 _ . _ _ _ f _   w . w w w . w   w _ F G F _ w     w H D _ w w w w
 _ . _ _ _ . _   w . w w w . w   w _ F F F _ w     w w w _ _ _ _ _
 _ . . . . . _   w . . . . . w   w _ _ _ _ _ w     w w w _ w   
 _ . . . . . _   w . . . . . w   w _ _ _ _ _ w     w w w _ w   
 _ . _ _ _ . _   w . w w w . w   w _ F F F _ w     w w w _ w w w w
 _ . _ _ _ f _   w . w w w . w   w _ F G F _ w     w H D _ w   
 _ . _ _ _ . _   w . w w w . w   w _ F F F _ w     w w w _ w   
 _ . . . . . _   w . . . . . w   w _ _ _ _ _ w     w w w _ w   
 _ . . . . . _   w . . . . . w   w _ _ _ _ _ w     w w w _ w     
 _ . _ _ _ . _   w . w w w . w   w _ F F F _ w     w w w _ w   
 _ . _ _ _ f _   w . w w w . w   w _ F G F _ w     w H D _ w   
 _ . _ _ _ . _   w . w w w . w   w _ F F F _ w     w w w w w   
 _ . . . . . _   w . . . . . w   w _ _ _ _ _ w             
                               
 w  natural rock wall                             
 f  constructed floor                             
 .  open space                             
 _  natural floor                             
 G  grate                             
 H  floor hatch (hooked up to drain lever)                             
 D  door (hooked up to flood lever)   
 F  fortification       

The main difference is the placement of fortifications in the squares adjacent to the grates on z0, with supporting natural rock above. This should allow the water to flow out of the grate and onto the squares occupied by the enemy, while at the same time preventing them from stepping under natural rock (which would prevent freezing and death). z-1 is largely the same.

I have not tested this yet because I am hopelessly occupied with trying to get the perfect embark for this: 1x1 glacier/tundra with aquifer, sand, clay, plentiful minerals, nearby tower, etc. Which ridiculous when I type it all out.

I would like to know if this trap will work before I sink more time into a major aquifer breaching operation. I am not entirely sure the fortifications will not freeze. Maybe someone else with a more generous allowance for embarks will try it out?

[Bumber]

I am not entirely sure the fortifications will not freeze.

They shouldn't since they're under natural walls, just like the grate.

[Larix]

You'll need an extra device to drain water from the grate/fortification array between uses: to re-arm, you'll need to mine away (or melt, but you don't want to use magma) the ice. If there's still spreadable water in the fortifications, it can spread to the freshly-mined squares, insta-freezing them again. This can be harmful to your miners.

I think aquifer plus glacier isn't a very likely combination. Glaciers have no soil under them, which makes aquifers rare, if they can occur at all. And to keep water liquid, you must put it under natural rock/soil - water freezes (instantly) on the ice levels of a glacier. Only makes sense - those levels _are_ ice, after all.

[bumblepuppy]

Good point about the extra drainage, thanks. I forgot there would be water remaining in the fortifications. I have actually got a glacier/aquifer combo, but I am currently working on tundra. It has sand and soil, and the only benefit a glacier has is ice at the start, which I can make anyway if I want it so much.

Thank you both for your replies.

[Slogo]

You'll need an extra device to drain water from the grate/fortification array between uses: to re-arm, you'll need to mine away (or melt, but you don't want to use magma) the ice. If there's still spreadable water in the fortifications, it can spread to the freshly-mined squares, insta-freezing them again. This can be harmful to your miners.

I think aquifer plus glacier isn't a very likely combination. Glaciers have no soil under them, which makes aquifers rare, if they can occur at all. And to keep water liquid, you must put it under natural rock/soil - water freezes (instantly) on the ice levels of a glacier. Only makes sense - those levels _are_ ice, after all.

They're not likely, but they're possible. I played one recently actually.

[Max™]

I used an aquifer+glacier for GOBLIN SNOWCONE before:

Spoiler (click to show/hide)

[Urist Da Vinci]

An upgrade to this design is to have on z0 (exposed to the sky) a natural carved down stair path, and on Z-1 a plain floor (NO up stairs!). Water on z-1 will not freeze since the natural down stairs block sunlight, but water pressure can force water up to z0. You just need to control the water pressure with an underground, but higher elevation, reservoir and some doors/hatches/etc.

To reset, disable the water pressure and carve down stairs into the ice walls.

[bumblepuppy]

I built this trap after many save-scums. It does work, though it is very slow to fill up with only one aquifer tile for a water source. I realise now I can't put a hatch cover under a fortification, so it has to dry naturally, which takes forever.

Urist Da Vinci's new idea seems intriguing, and certainly much simpler to build. I'm a little concerned about enemies getting into the water supply, but I suppose I can trap it as well.

[Sadrice]

Put a grate somewhere between the cistern and the trap, so enemies would have to path up through the grate.  They can still get into the "nozzle" of the trap, so make sure you have a way to drain it and clear them out.