When using manifolded cylinders, how many pressure gauges are required for a dive?

In the context of diving with manifolded cylinders, the need for pressure gauges is influenced by how the system is set up. Manifolded cylinders typically have two or more tanks connected with a manifold, allowing for equalization of gas pressure and ensuring that gas can be accessed from either tank as needed.

In a properly configured manifold system, you only require one pressure gauge if you consider the entire system's pressure readings, as the manifold links the cylinders. This single gauge will give you the pressure reading of the combined volume of gas, which is sufficient for monitoring the overall supply during a dive.

While divers might choose to use additional gauges for redundancy or personal preference, it is not a requirement from a technical standpoint. Therefore, a manifolded system can function effectively with just one gauge, ensuring that divers can accurately monitor their gas supply without needing additional gauges from each cylinder, keeping the setup streamlined and efficient. The notion that no pressure gauges are necessary (option D) could stem from the idea that in a manifolded system, divers are primarily reliant on the single gauge and the general pressure of the setup. However, it’s always a best practice to use at least one gauge to ensure the divers are aware of their gas supply status.