Editing 40d:Hatch cover

{{av}}{{Quality|Exceptional}}
A '''hatch cover''' (also called a '''floor hatch''' or just '''hatch''') is a circular covering for a hole in the ground, effectively a horizontal door based on the Z-axis.  It is classed as {{L|furniture}} and can be built from either {{L|rock}}, {{L|wood}}, {{L|metal}} or {{L|glass}}.  When closed, hatches have the symbol {{Raw Tile|¢|0:7:1}}, and when open they "disappear", just like {{L|door}}s or {{L|floodgates}}.  You can verify the presence of an open hatch by using the {{k|k}} key and moving the cursor over/near the hatch opening. You can also use the {{k|t}} key to view the quality/value of an installed hatch.

When you create any stairway down between two floors, a Floor Hatch, when put on the upper floor, acts exactly like a door. If you lock it, the dwarves will not use that staircase. A closed floor hatch will block the passage of fluids onto the lower floor, and will stop falling creatures. They can also be used on ramps.  Up-down stairways do not prevent the use of hatches in that tile to block the down-portion - the up-portion would need to be blocked from the level above that.  Floor hatches can also be placed or grouped on open space, provided they have support.

== Hatch settings ==

There are three options one can specify on any door or hatch from the {{K|q}} menu:
* {{K|l}} Forbid/Permit Passage
** A hatch set to Forbidden is impassable to any dwarves in the game. A hatch cannot be set Forbidden if it is open. Invading thieves may lock-pick and bypass a Forbidden hatch.
* {{K|o}} Keep Tightly Closed/Make Pet-Passable
** A hatch that is pet-passable allows through traffic of pets. A pet can still pass through a hatch that is tightly closed if it does so while it is being held open by another creature.
* {{K|s}} Set as Internal/External
** While this setting has meaning with {{L|door}}s, it is meaningless for hatches, as room definitions do not span Z-levels.

== Building Hatches ==

After constructing a hatch at any of the above workshops, they must be "{{K|b}}uilt" (placed) like all other furniture.  Hatches can be built on any free floor tile, over empty space, or on top of down-staircases (or up/down staircases, or even up-staircases, although that last option won't do anything useful). Hatches cannot be placed on the same tile as most other constructions, including all {{L|furniture}} and {{L|trap}}s.

To be used effectively, a hatch should either be placed above a downstair (or in an up/down stair) where, like a door, it will impede liquid flow while still allowing access; or alternatively it can be linked up to a lever (and probably placed above a channel, or lava, or below a river etc.), which when pulled will temporarily open the hatch, allowing whatever is above to fall down below.

Like {{L|grate}}s, hatches placed on top of floor tiles are purely decorative. Placing a hatch cover does not automatically dig out anything under the hatch.

Water which has a hatch on top of it can still be used as a water source and for fishing.

Hatches over empty space can be safely walked on and even driven over by caravans (They do need to be next to a wall or floor for support, however, but they can't even be built if that condition isn't met - and supports on the level below don't do any good {{verify}}).

== On using Hatches ==
*They work just like doors. Only on the Z-axis.
*The hatch will be flashing if placed over stairs or ramps.
*Trap doors when hooked to pressure plates 
*For use over pits and ponds 
*Cover for stockpile stashes hidden underground 
*Preventing water and magma from flowing down stairs or ramps - useful for aquifer levels
*Last minute defense for an invasion (Mainly for fortress built right into the ground)
*A dwarf falling down a multiple floor stairway will be stopped by a closed floor hatch.
*Hatches can be linked to levers to function like a "vertical" floodgate without blocking liquid accumulating on the surface above - for example they can be used as emergency drains for pools of water - or magma, if made of magma-safe materials.  
*Hatches can be deconstructed by creatures with the {{L|building destroyer}} tag, like {{L|troll}}s or {{L|cave crocodile}}s.
*Freezing water has been reported to deconstruct hatches, causing flooding when the water thaws (and leaving the hatch lying nearby the opening).
*Can be used to halt enemies coming from below the hatch, as enemies must be on the same level as their target (or higher) when making a melee attack. This might not work if an enemy's body temperature is high enough to damage the hatch.

{{Colored Notice Box|#FF00FF|More testing is required.}}

{{buildings}}
{{Category|Furniture}}