Open Water Diver Flashcards

I can utilize my backup computer to finish the dive if my primary computer malfunctions. If I don't have a backup on, I ought to:

Answer: Ascend (go upward), halt for safety, and stop the dive.

If a primary dive computer malfunctions and no backup is available, the safest and most responsible action is to immediately end the dive. This involves making a controlled ascent, including a safety stop, to minimize the risk of decompression sickness. Continuing the dive without essential depth and time information is extremely dangerous, and relying on another diver's computer is not a safe personal solution.

Unless specifically stated otherwise by law, I should remain within ___________ of my dive flag.

Answer: fifteen meters

Dive flags are vital safety markers that alert surface vessels to the presence of divers underwater. Staying within fifteen meters (50 feet) of the dive flag ensures divers remain within the protected zone it designates. This regulation is crucial for preventing collisions and enhancing diver safety by clearly indicating their location to boats.

Decompression sickness (DCS) is more likely to strike me if I:

Answer: dive when you're dehydrated, sick, cold, or hurt.

Certain physiological conditions significantly increase a diver's susceptibility to decompression sickness (DCS). Diving while dehydrated, sick, cold, or injured can impair the body's ability to efficiently off-gas nitrogen, making DCS more likely. Maintaining good health and hydration is crucial for minimizing dive risks.

Two dives are planned by a group of advanced open water divers. The first dive lasts 20 minutes on a reef in a depth of 22 meters. After that, the group spends an hour on the surface. The second dive is scheduled to take place on a wreck in 18 meters of water, with a 30-minute bottom duration. After the second dive, what pressure group will finish first?

Answer: R

To determine the final pressure group, one must apply the PADI Recreational Dive Planner (RDP) or equivalent dive computer logic. After the first dive (22m for 20min) and a 60-minute surface interval, residual nitrogen is calculated. For the second dive (18m for 30min), this residual nitrogen is added to the actual bottom time. Following these calculations according to dive planning rules results in Pressure Group R.

I begin my dive feeling a slight stream. How should this dive start for me?

Answer: Jump into or against the current.

When entering the water with a slight current, it is generally recommended to jump into or against the current. This allows divers to descend quickly and get below the main force of the current, where it is often weaker and easier to manage. Entering with the current could cause divers to be swept away from their intended descent point or boat.

Which of these tasks is necessary to properly maintain my scuba cylinder?

Answer: Don't forget to add air.

Proper maintenance of a scuba cylinder includes ensuring it is filled with clean, dry, breathable air before each dive. While cylinders require periodic visual inspections and hydrostatic tests, 'adding air' (i.e., filling it) is the most frequent and essential task for its immediate use. Incorrect practices like letting it air dry in the sun or monthly pressure tests are not proper maintenance procedures.

Gas narcotics may cause divers who behave foolishly at depth to revert to their usual behavior if they

Answer: climb up to a level that is shallower.

Nitrogen narcosis, or gas narcosis, is a reversible impairment of mental and physical abilities caused by breathing gases under pressure at depth. The effects of narcosis typically diminish rapidly as a diver ascends to a shallower depth. Ascending is the immediate and most effective remedy to alleviate the symptoms of narcosis and regain normal cognitive function.

My intention is to take two dives. The first dive lasts 49 minutes at a depth of 18 meters. The second dive lasts 24 minutes at a depth of 18 meters. For these two dives to be done safely, how long would I need to spend on the surface (minimum surface interval)?

Answer: Thirty-two minutes

To calculate the minimum surface interval for repetitive dives, one must use the PADI Recreational Dive Planner (RDP) or a dive computer. After the first dive of 18 meters for 49 minutes, the diver would be in a specific pressure group (T). To safely complete a second dive of 18 meters for 24 minutes, the RDP's surface interval table indicates that a minimum of 32 minutes on the surface is required to off-gas sufficient nitrogen.

Select the option that best fits the signal displayed among the available options.

Answer: There's a problem.

While the specific image is not provided, the universal underwater signal for 'There's a problem' or 'Something is wrong' typically involves waving an open hand back and forth, palm down, or pointing to oneself while making a questioning gesture. This signal alerts a buddy or dive leader to an issue requiring attention or assistance, distinguishing it from 'OK' or 'ascend/descend' signals.

I take two dives in one day and catch a commercial flight home. I should hold off until ________ hours, or until my computer indicates I can take off, whichever comes first.

Answer: 18

PADI guidelines recommend a minimum surface interval of 18 hours after multiple dives or dives requiring decompression stops before flying on a commercial aircraft. This extended interval allows the body sufficient time to off-gas residual nitrogen, significantly reducing the risk of decompression sickness at altitude. Divers should always follow the more conservative recommendation between dive tables/computers and general guidelines.

When I move downward, my wet suit will

Answer: I will get thinner due to the pressure of the water, losing my buoyancy and warmth.

As a diver descends, the ambient water pressure increases significantly. This pressure compresses the neoprene material of a wet suit, making it thinner. A thinner wet suit provides less insulation, leading to a loss of warmth, and displaces less water, resulting in a loss of buoyancy.