Tutorial [How-to] Simple Two-Stage Ocean Airlock

After not seeing any decent recipes online, I figured I'd post one myself. I've gone through a couple iterations of airlocks for my underwater base, and I've managed to boil the design down to six logic gates and a switch.

1. Start by designing your airlock. Placing background tiles to outline the base will avoid those "leaky" spots that are created when removing portions of ocean. For this design to work, though, be sure to incorporate a 4-block ceiling, or failing that, a 7x4 area for the flow valve. Water needs to come in through the ceiling, otherwise the filling process takes a long, long time.
2. Place the following structures:
   • An outer door - Something that looks decent with water up against it. Any thick bulky doors will work, though in this example I used large outpost airlocks. Ship doors also work well.
   • An inner door - As above
   • A fill valve - Any vertical hatch will do. If you need one, a mining hatch blueprint can be obtained from the first mission through random crate loot.
   • Three buttons - They need to be buttons, not two-state switches. The design gets cranky if you leave the power on. Place one outside the airlock in both directions, and one inside. This will prevent you from getting locked in or out.
   • Floor drains - The more they are, the faster the drain cycle goes. I've placed the drains in a recessed area behind a grate of alternating blocks and platforms, but this will work if you use drains on a flush floor if you can live with the increased delay in the door opening.
   • Alarm - Purely optional. It will only activate when the airlock is draining or filling.
   • Drain sensor - A liquid sensor low to the ground. You can put it in the recessed area for an increased delay before the inner door opens. But where it is, you won't have any issues with water spillage.
   • Fill sensor - A liquid sensor high in the airlock. The outer door will open as soon as water touches it. If you're getting some "jitter" when the door opens, place it a little lower. Depending on the design, the outer door opening can lower the water level enough to trigger the door to close again.
3. Place an AND gate in your wiring area. Top input goes to BOTH doors, bottom input goes to all three buttons. This will prevent the cycle from being interrupted (ie: when both doors are closed, the buttons won't flip the switch). If you'd rather be able to interrupt a fill/drain cycle, simply wire the buttons to the switch in the next step.
4. Place a wall switch in the wiring area. This is a state switch, and won't be toggled directly. Connect the input to the output of the AND gate from step 3, and connect the output to all the floor drains.
5. Place a NOT gate. Wire the input to the switch, and the output to the fill valve.
6. Place an AND gate. Top input goes to the NOT gate in step 5. Bottom input goes to the fill sensor. Output goes to the outer door. This will prevent the outer door from opening until the airlock is filled.
7. Place a NOT gate. Input goes to the drain sensor.
8. Place an AND gate. Top input is the NOT gate from step 7. Bottom input is the switch from step 4. Output goes to the inner door.
9. Place a NOT gate. Input goes to BOTH the doors. Output goes to the alarm.

And that's it, you're done! I'm still tweaking the design, so I'm open to suggestions.

 

I like the effort you put into this, it's a very cinematic approach to a sea base.

Personally, I just have some drains and a water sensor on the floor set up so that my airlock won't open to the inside if there is any water. Then I just open the outside door whenever I need to and once I close it, what water gets in drains automatically.
(Basically, I don't need to fill the airlock with water ever and, consequently, draining is much faster as I rarely need to fully drain the airlock)

Still, the warning lights are a nice touch.

 

I'll try to use this this in my next ocean base, the warning lights are an excellent touch

 

What do you mean "Place one outside the airlock in both directions?"

 

he meansone on the outsode of the air lock (the ocean side, the "wet side") and one on the inside (the base said, the "dry" side), now if you want to be technical there is also a button on the inside of the airlock, but thats a different step

 

Please please please please please tell me how your doors are not soaked with water? Everytime i make an airlock once the door opens and water passes over it the water gets stuck over the door once it closes. Have you found a way to fix this??