| RDP Recreational Dive Planner |
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Dive tables are used to gauge how much excess nitrogen you have in your body, so you can determine your maximum safe time and depth limits. These limits can only be found through the use of dive tables, such as the Recreational Dive Planner. Be aware that although dive tables give you maximum limits, you need to dive conservatively, avoiding the maximum limits.
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This is especially true if any of the factors that contribute to decompression sickness (vigorous exercise, cold, older age, etc), apply to your situation. Take extra precautions to not allow yourself to become dehydrated, for example, especially after several days of diving. Because people differ in their susceptibility to decompression sickness, no dive table can guarantee that decompression sickness will never occur, even though you dive within the table limits.
The Recreational Dive Planner was designed solely for no-decompression diving. No-decompression diving means that while staying within the limits of the table, you may ascend directly to the surface at any time during the dive without significant risk of decompression sickness.
Recreational diving is always planned as no-decompression diving. Dive tables designed for commercial or military diving differ from the Recreational Dive Planner. Commercial or military divers generally stay at a given depth for time well beyond recreational time limits, so they use tables that were developed with decompression diving in mind.
Decompression diving involves making a series of difficult and complex stops during ascent to avoid decompression sickness. Decompression diving requires significant surface support and emergency preparation, and lies beyond the scope of recreational diving because it can be quite hazardous. Using tables designed for decompression diving to plan no-decompression dives is safe, however recreational dives should never plan decompression dives.
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| Be a S.A.F.E Diver |
| Slowly Ascend From Every Dive - no faster than 18 metres per minute, which is slower than you many realize. As a new diver, you may find it a little difficult to judge your rate of ascent at first. Always start your ascent with plenty of air to allow a slow, leisurely trip to the surface. |
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Be a S.A.F.E diver and Slowly Ascend From Every dive.
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| Safety Stops |
| A safety stop is a delay in ascent at 5 metres for 3 minutes. This delay assists your body in slowly eliminating excess nitrogen. The guideline for making a safety stop is simple: You may make a safety stop at the end of any dive. In fact, it's encouraged. However, always make a safety stop if: |
| 1. Your dive has been to 30 metres or deeper. |
| 2. Your pressure group at the end of the dive is within three pressure groups of the no-decompression limit. |
| 3. Your dive up to any limit on the Recreational Dive Planner. |
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Emergency Decompression
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If you accidentally exceed the time limits of the Recreational Dive Planner, you need to know the procedure for an emergency decompression stop so you can make a safe ascent to the surface. If you exceed a no-decompression limit by no more than 5 minutes, slowly ascent at a rate not faster than 18 metres per minute to 5 metres and remain there for 8 minutes prior to surfacing. After reaching the surface, do not dive for at least 6 hours because you will have extremely high levels of residual nitrogen in your body.
If you exceed a no-decompression limit by more than 5 minutes, a 5-metre stop for no less than 15 minutes is strongly urged, air supply permitting. Upon surfacing, you must remain out of the water at least 24 hours before diving again, due to the excess nitrogen in your body.
Emergency decompression stops differ from safety stops in that an emergency decompression stop 1) must be made or there is an excessive risk of decompression sickness, 2) is an emergency procedure only.
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| Diving at Altitude |
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You've already learned that as you ascend through air, pressure decreases - just as pressure decreases as you ascend through water. The Recreational Dive Planner was designed for diving at sea level and may not be used at altitude greater than 300 metres. Above 300 metres, special tables and procedures are required to account for the decreased atmospheric pressure.
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| Flying After Diving |
| The lowered atmospheric pressure at altitude must also be considered if you intend to fly after diving. The following are general guidelines for determining when to fly: " A minimum surface interval of 12 hours is required to be reasonably assured you remain symptom free from decompression sickness upon ascent to altitude in a commercial jet airliner " If you plan to make daily multiple dives for several days or make a dive requiring decompression, you should take special precautions and wait for an extended surface interval beyond 12 hours before flight. |
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| Cold and Strenuous Conditions |
| Cold or strenuous conditions may cause your body to have more excess nitrogen at the end of a dive than normally expected. When planning a dive in cold water or under conditions that may be more strenuous than usual, plan your dive as though the depth were 4 metres deeper than it actually is. |
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| Dive Computers |
| The use of electronic dive computers has become a popular approach to monitoring depth and time limits while diving. Dive computers are relatively inexpensive and offer an easy way to record your dive profile and nitrogen absorption. Dive computers calculate multilevel diving. This increases dive time as the diver moves to shallower depths, where nitrogen absorption is slower. In addition, the dive computer often incorporates most of the required diving instruments into one compact package. |
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