The Oxygen Tank is used to explore the Ocean Floor through Underwater Diving. It can be crafted with 50 
Iron Bars at 19 Crafting after unlocking the ability from the Tier 2 Fishing Research. An underwater dive will take three hours, and during this time you will not be able to catch fish from your fishing equipment.
After returning from the dive, you will receive various types of fish, in addition to other unique items including Fish Bones, Seaweed, Oysters, as well as items required for progression in the game, such as the Boat Blueprint (after unlocking the Fishing Tier 3 Research) to craft a Row Boat, and Blue Spice for The Stew Chef quest. In addition, you can also receive the Small, Medium, or Large Shell, which can be sold to the Museum.
 Buildings and Machines 
| |
|---|---|
 Tiered
|
 Community Center •  Oil Wells •  Oil Factories •  Oil Storage  Furnaces •  Foundry •  Ovens
|
 Home
|
Cabin • Castle •  Mansion •  Museum
|
 Mining
|
 Drills •  Crushers •  Giant Drills •  Excavators •  Robot • Rocket
|
 Farming
|
 Planter
|
 Fishing
|
 Oxygen Tank •  Row Boat •  Canoe Boat
|
