Section 4, Equipment IV

(15) What is residual nitrogen? What is a repetitive dive?

The nitrogen left in your body after a dive

(6) What items might I have in a spare parts kit?

- Spare mask strap, fin strap, snorkel keeper - Harness/weight belt buckle - Cable (pull) ties - Adjustable wrench (spanner), pliers, screw drivers, hex wrenches (Allen keys) or scuba tool. - Regulator mouthpiece - Accessory clip - Slate/wet book pencil - Various sized cylinder calve/DIN valve o-rings - Cement or glue appropriate for exposure suit repair - Sunscreen and spare sunglasses

(9) For practical purposes, what percent of each of the component gases does air consist of?

79% nitrogen and 21% oxygen

(14) What is the difference between a decompression stop and a safety stop?

A safety stop is recommended for conservative diving but not required. Decompression stops are an emergency procedure that you do when you exceed no stop limits. No doing the decompression stops when necessary creates high risk of decompression sickness.

(16) How do I plan dives with my dive computer?

Activate your computer, agree with buddies on a maximum depth based on the no stop times displayed.

(7) what are the 2 most common substances that I should refrain from using before diving, and why?

Alcohol and tobacco. Smoking harms your circulatory and respiratory systems and can raise the risk of lung over expansion injury. Alcohol affects your judgment and effects can increase with depth.

(7) What are the recommendations for using prescribed or over-the-counter medications before diving?

Ask your doctor.

(14) Why is my ascent rate an important part of a no stop dive?

Because no stop times assume that your ascent rate is no faster than 18m/60ft per minute, or the ascent rate of your computer (whichever is SLOWER).

(15) Why is it important that I dive with the same computer on every dive I make on a given day and not turn my computer off between dives?

Because that computer has your residual nitrogen information, diving without that same computer in that day should not be done and is dangerous.

(1) What would I use a mesh utility bag for?

Carrying bulky items that are difficult to carry.

(2) For what 4 purposes might I carry a slate or wet book?

Communication, to note the dive plan limits, to record information during the dive, and the unexpected

(12) What condition can result if I exceed established depth and time limits while diving, and then surface? What happens in the body that causes this condition?

Decompression sickness/ the bends. Nitrogen levels in your body tissues is too high, when you ascend nitrogen comes out faster than your body can eliminate it, forming bubbles in the body.

(12) What 2 primary factors influence how much nitrogen dissolves into my body tissues during a dive?

Depth (pressure) and time

(8) How do I keep my dive skills and knowledge current and refreshed?

Dive regularly. Involve yourself with the dive community.

(10) How do I prevent problems with oxygen when diving with air?

Dive within recreational depth limits (40m/130ft). Never use a cylinder with greater than 21% in oxygen content.

(7) What should I do if I feel ill before a dive?

Do not dive.

(9) How does using enriched air nitro affect the component gases that make up air?

Enriched air nitrox (EANx) is gas with 22% or greater oxygen content.

(5) What can I do with dive planning software?

Estimate how long your air supply will last and estimate the time your dive computer will allow on a dive.

(12) Besides dive time and depth, what 9 secondary factors are thought to influence how the body absorbs and releases dissolved nitrogen?

Fatigue, cold, illness, age, alcohol consumption before/after the dive, vigorous exercise before/during/ after the dive, dehydration, poor fitness/ high body fat, injuries

(11) How do I avoid contaminated air problems?

Fill only at reputable sources that take it seriously.

(16) How do I set up and activate my dive computer? What is the first step?

First step is to read the dive computer manual. You usually set up: time and date, metric/imperial system measurements, ascent rate alarm, maximum depth/ time alarm.

(5) What options do I have with dive planning software?

For desktop, laptop, or tablet.

(11) What are some possible causes of contaminated air?

Getting a cylinder filled at an improper source, improper maintenance of the filling system, very high levels of contaminant at the source.

(11) What should I do for a diver who I suspect breathed contaminated air?

Have them breathe fresh air, give emergency oxygen if available, *if they are not breathing* start CPR, contact EMS ALWAYS

(11) What are 5 possible signs/symptoms of contaminated air?

Headache, nausea, dizziness, unconscious/ unresponsive, cherry-red lips or fingernails

(1) Why should I be cautious about attaching a mesh utility bag to my gear while diving?

In an emergency you need to be able to quickly drop weight/drag. It could also snag or get entangled.

(10) Why shouldn't I dive with a cylinder labeled "oxygen" or known to be filled with 100 percent oxygen?

It can be toxic at relatively shallow depths. You are not trained to use it.

(10) Why is it important to be trained as a PADI Enriched Air Diver, or under the supervision of a PADI Enriched Air Instructor, before attempting to dive with enriched air?

It can be toxic, and is very dangerous to use if you don't know what you're doing.

(15) What happens to the dissolved nitrogen in my body during a surface interval?

It declines as it dissolves out of your tissues and leaves your body.

(15) How does my dive computer calculate repetitive dives?

It remembers the amount of residual nitrogen left in your body and accounts for it in calculations.

(15) How does residual nitrogen affect the no stop limits on a repetitive dive?

It shortens the no stop limits.

(15) How do dive tables address repetitive diving?

It uses three tables. Table one assigns a pressure group that represents the theoretical amount of residual nitrogen from your dive time and depth. Table two gives you credit for the nitrogen leaving your body during a surface interval. Table three shows your no stop time for each depth adjusted to your pressure group.

(13) How does a dive computer or dive table estimate the amount of nitrogen I absorb during a dive?

It uses your dive time and depth information and compares it to a mathematical decompression model. It is not actually measuring the amount of nitrogen in the body.

(7) What general recommendations apply to my fitness as a diver?

Maintain a reasonable level of fitness, keep immunizations current, eat a well balanced diet and get adequate rest, get regular physicals.

(9) What component gases make up air?

Nitrogen, oxygen, and trace gases

(13) Does a dive computer or dive table directly assess anything going on inside a diver's body?

No

(18) Are divers a significant threat to the overall health of the underwater environment?

No

(16) What 7 types of information do dive computers tell me before, during and/or between dives?

No stop limits, depth, elapsed time, no stop time remaining, ascent rate, emergency decompression stops, previous dive information

(7) What effect does mensuration have on diving?

Not any more than it would affect regular physical exercise.

(18) Why is it important to apply environmentally friendly dive skills and awareness while underwater?

Not doing so can destroy the ocean's natural beauty. A struggling ecosystem may be too weak to recover from damage from divers. These skills are also good for you and your gear.

(7) Why is it recommended that pregnant women not dive?

Not much is known on the harm diving could cause a fetus.

(17) What should I do if my dive computer fails during a dive or between dives?

Option 1: Signal buddies, ascend, make safety stop, end the dive. Option 2: Continue the dive using a backup computer. You must have dived with the backup at all times that day, and stay within the limits of the most conservative one. Note: If you're writing down your dive depths and times, you may be able to do another dive by applying all the information to dive tables. Otherwise, wait 12 hours for your nitrogen levels to return to normal.

(9) To what 4 diving related issues does the makeup of air relate?

Oxygen toxicity, decompression sickness, contaminated air, gas narcosis

(7) How often is it recommended that I have a complete physical exam for diving?

Regularly.

(12) What are 9 signs/symptoms of decompression sickness? How soon do they occur after a dive?

Signs/symptoms: Paralysis, dizziness, tingling, joint and limb pain, shock, numbness, difficulty breathing, weakness and prolonged fatigue, (in severe cases) unconsciousness and death This occurs 15min to 12 hours after the dive

(2) What options can I choose from when choosing slates and wet books?

Size

(3) What options can I choose from when selecting dive lights?

Size, brightness, and power source.

(7) What should I do as a diver if I am or may be predisposed to heart disease?

Speak to a doctor.

(1) What options can I choose from when selecting mesh utility bags?

Style, material, size, straps or handles.

(14) What is the relationship between depth and my no stop limits?

The deeper you dive, the shorter your no-stop limits.

(14) What is a no stop (no decompression) limit?

The maximum time you can spend at a given depth and still ascend directly to the surface.

(15) What is a surface interval?

The time you spend on the surface between dives

(4) What options can I choose from when selecting a dive log? What information do I typically record, at a minimum, regardless of which I choose?

There are printed logbooks and electronic logbooks. At a minimum, record: date, dive site, dive buddies, depth and duration, objective/description

(13) Why can no dive computer or table guarantee that decompression sickness will never occur, even within its limits? How do I address this concern?

There are secondary factors that can add to your danger level, if you have secondary factors, be even more conservative with your depth and time spent at high pressure.

(16) What are the 4 advantages of dive computers over dive tables?

They are easier to use, help offset human error, give you more time underwater, they have other additional features

(14) What happens to my no stop limits as I ascend to a shallower depth during a dive?

They will increase in length.

(6) Why is it important to have a spare parts kit?

To save a dive! Replace parts that are user-replaceable.

(4) Why do I log my dives?

To validate the training you receive. Reference, documentation, onsite experience reference, to share, and related information.

(8) How do I refresh my dive skills and knowledge after a period of inactivity? As a new PADI Open Water Diver, after what interval of inactivity is this recommended?

Use the PADI ReActivate program after 6 months of inactivity.

(14) What is no stop (no decompression) diving?

When you plan your dive so that you can, if necessary, swim directly to the surface without unacceptable risk of decompression sickness.

(18) What role do I have as a diver in the long-term survival and health of the world's aquatic ecosystems?

You have the power to take direct action! (do cleanups and invasive species removal)

(8) How does continuing my diver training help keep my skills refreshed?

You keep diving and learn new things at the same time.

(14) What do I have to do if I exceed a no stop limit?

You must make one or more emergency decompression stop. These are stops at specific depths for prescribed times to allow your body to release dissolved nitrogen before you ascend further.

(3) What would I use a dive light for? Why might I use one during the day?

You use a dive light to see in the dark, usually at night. They can be used in the day to see into dark holes and cracks.

(7) What factors in diving can strain my heart and cardiovascular system?

swimming hard, carrying equipment, climbing a ladder, long walks wearing gear, heat stress.