Fore ballast water
Aft ballast water
Blow air bubbles
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This simulator models the two forward and aft trim tanks that real submarines use to control depth and pitch. Flooding a tank adds seawater mass while the boat's fixed hull volume keeps displacing the same amount of water, so the balance between buoyancy and total weight sets whether the boat rises, sinks, or holds depth — and any imbalance between the fore and aft tanks tips the bow up or down. Blowing a tank empty uses stored high-pressure air, and that only works while the reservoir pressure beats the ambient sea pressure pushing back, so the simulator enforces a real depth limit on how effective a blow is. Adjust the fore and aft targets, the valve rate, and the HP air reserve, and watch depth, pitch, and vertical speed respond in a live 3D cutaway.