Saturation Diving 100m Guide: Oxygen, Sonar & Pressure

How do you prepare for a 100m Saturation Diving run?

At 100m you are still in the Continental Shelf, so use Heliox and a Reinforced MK-I suit. The important change is operational: visibility is no longer reliable enough for a continuous-light route, and oxygen must be protected for both navigation mistakes and the staged ascent.

100m route check	Standard
Depth zone	Continental Shelf (40–120m)
Gas	Heliox — 18% O₂, 82% He
Suit	Reinforced MK-I
Oxygen reserve	35%
Navigation	Short pulse-sonar pings
Avoid	Continuous floodlights

Why should you use sonar instead of floodlights at 100m?

Use pulse sonar for short orientation checks and keep high-beam floodlights off whenever the route does not require them. Continuous light increases predator detection range and removes the crew’s ability to control when it announces its position.

Hold the team on one route line: the front player pings, the middle players maintain sight of the return direction, and the last player confirms that the formation has not split. A crew that keeps its lane saves more oxygen than a crew that sprints through a wrong turn.

What should you not do at 100m?

• Never ascend while holding sprint; barotrauma causes instant death within three seconds.
• Do not mix Standard Air with Heliox canisters; gas corruption vents the full reserve.
• Do not spend the 35% return margin on optional extraction.

Finish with the SD-W 45/10 Ascent Rule. The Decompression & Gas Calculator gives the depth-based crew checklist, while the Deep Diving Guide explains the full equipment order.