Dive professionals use the term “open water” frequently. The term is used in a variety of ways such as “open water dive,” “open water course,” and simply “open water”. What does it mean?
Open Water Dives:
During a scuba certification course, instructors use the phrase “open water dives” to describe training dives that simulate (or take place in) realistic scuba diving conditions. Most scuba certification agencies set further requirements for open water training dives. For example, one dive training organization defines an open water dive as a dive within the recreational dive limits during which a diver spends the majority of his time deeper than 15 feet. In addition, the diver must use at least 50 cubic feet of gas or stay underwater for at least 20 minutes.
An open water training dive:
• never takes the diver beyond recreational dive limits
• never requires decompression stops unless the diver is trained (or training) for decompression diving
• never is conducted in an overhead environment such as a shipwreck or cave.
• never requires the diver to use trimix unless the diver is trained (or training) to do so.
• never is conducted at night unless the diver is trained (or training) to night dive.
Open water training dives are often referred to as check out dives because instructors check that student divers can preform required scuba diving skills, such as mask clearing, in a realistic dive environment (as opposed to a pool or other confined water location).
The Open Water Course:
The open water course is a recreational scuba diver training course which teaches students to safely explore the underwater world within certain limits such as depth (no deeper than 130 feet) and environment (no locations in which a dive cannot directly swim to the surface). The open water course includes lessons in dive theory
and planning, scuba skill practice in shallow, confined water
, and final check out dives during which students put their knowledge and skills to the test. Once a diver successfully completes his open water course, he is allowed to dive within the recreational dive limits in conditions similar to those in which he was trained with just a dive buddy (no instructor) present.
The term "open water" generally refers to a dive environment that does not require a diver to descend deeper than 130 feet, does not require the diver to exceed his no-decompression limit
, and allows the diver to ascend directly to the surface. The term is most commonly used to define dive sites that are deeper than 15 feet and are not a “controlled environment” such as a swimming pool or a calm, shallow bay. For example, drift dive over a coral wall is in open water, even if the ocean floor is thousands of feet below, provided that a diver does not descend below 130 feet. Cave, shipwreck interiors, flooded mines, or frozen lakes are not considered open water because the diver must navigate back to his entry point before he can ascend.