A simple mod for extending one's underwater excursion time.
Air tanks are crafted from copper, steel, or bronze ingots and are wielded like tools. A compressor is crafted from steel, mese shard, and wood.
Place a compressor in world and click on it with an empty air tank to fill it. Compressors can also recharge partly-used tanks.
When running low on breath use a filled air tank to recharge your breath bar. One use will replenish 5 steps of breath (out of 10). By default a steel air tank will hold 30 uses, a bronze one holds 20, and a copper one holds 10 - these settings can be changed in the mod's section under Advanced Settings. Once a tank runs out of uses it turns into an empty tank, which can be recharged again with a compressor.
To automatically draw air from air tanks, craft a breathing tube and put it in your quick-use inventory row. When your breath bar drops below 5 steps it will automatically attempt to use an air tank from your quick-use inventory row to replenish it.
A solid mod
I like this mod because it is simple and it works.
I think it would be even better if the only tier of air tank was steel, and the copper/bronze tiers were removed. The copper/bronze tiers just don't add much to the mod. Players typically don't spend much time on the copper/bronze tier of tools before getting to steel.