For divers, going underwater to retrieve objects, artifacts, or other materials is second nature. They don't mind getting wet, as it is part of what they do.
However, there are cases when it's unsafe to go diving in certain areas such as those with rapid currents. So, they make use of specialized chambers which allow them to go underwater without getting wet. They are called diving bells. Currently, there are two diving bell ships in operation at the Rhine River.
The way the chamber works is that when it goes down, air is pumped into the chamber pushing the water out, at which point, the divers can descend the chamber to collect the items they are searching. But before going down, divers acclimate themselves in a pressurized cabin to get used to the atmosphere inside the chamber.
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