De-Dr

Decompression Diving

Decompression diving involves making a series of predetermined stops at predetermined depths during ascents from dives exceeding no-decompression limits. These stops help facilitate the off gassing of nitrogen from the body in an effort to avoid decompression illness.

Because Hoofer SCUBA is considered a recreational dive club, we do not condone the regular practice of decompression diving among its members, especially during authorized club dive trips. Exceptions to this rule are limited only during emergency decompression procedures.

If a no-decompression limit is exceeded by no more than 5 minutes, an 8-minute decompression stop at 15 feet is mandatory. Upon surfacing, the diver must remain out of the water for at least 6 hours prior to making another dive. If a no-decompression limit is exceeded by more than 5 minutes, a 15-foot decompression stop of no less than 15 minutes is urged (air supply permitting). Upon surfacing, the diver must remain out of the water for at least 24 hours prior to making another dive.

Decompression Illness (DCI)

All dives involve some form of decompression, which normally takes place during the ascent and subsequent period on the surface. It follows that it is as important to correctly perform these stages, as it is to monitor the dive itself. Dive computers can assist in this if they are correctly used and are programmed to an appropriate algorithm. This means for a simple rectangular profile they should give dive times as conservative as the PADI Recreational Dive Planner (RDP).

It is important to realize that both tables and computers are unable to make allowance for factors such as age, fitness, exertion, obesity and injuries, which may all significantly affect susceptibility to decompression illness (DCI). Divers should therefore be aware of these factors and avoid diving beyond their limits. Take particular care when planning repeat dives.

Where two or more dives are being made the same day it is good practice to carry out the deepest dive first. It is also good practice to achieve maximum depth as early in the dive as possible and to avoid re-descending once any ascent has commenced.

Decompression illness symptoms vary so suddenly, that immediate air evacuation to a chamber is vital, to symptoms that may not become apparent for some hours. Some of these less dramatic symptoms may well be delayed but can be more serious and produce greater disability than the excruciating pain often associated with DCI in a joint. Tingling and numbness are included in this category. Severe DCI symptoms, occurring at sea, require rapid transfer of the subject to a recompression chamber, laid on their left side and if possible, the administration of 100% oxygen. Being bounced, repeatedly, in a small boat is almost certainly going to worsen the symptoms rather than help the situation.

If someone is suspected to have DCI and is in the recovery position, DO NOT allow them to sit or stand up until properly trained rescue personnel have arrived as this could result in an air embolism.

For assistance with decompression illness, advice in the United States can be obtained from the Diver’s Alert Network (DAN) at (919)-684-8111 or (919)-684-2948.

When at sea, contact should be made via the U.S. Coast Guard on VHF Channel 16. When on shore, the Traverse City Air Station Coast Guard can be contacted at (616)-922-8214.

Delayed Surface Marker Buoy (SMB)

Surface markers can be used in many diving scenarios; they can be used in the event of an emergency or to maintain communication with the surface contingent of a team while divers are completing safety stops.

A Delayed SMB is no substitute for a fixed mooring line and wherever practical a mooring line should be used for the ascent and descent phases of the dive. However there are situations where the use of a mooring line or a conventional SMB may not be appropriate, and in these circumstances consider the use of a Delayed SMB. Ensure that you practice deployment and usage of the Delayed SMB in safe, simulated conditions before using one in earnest, and when deploying the Delayed SMB do not attach the free end of the line or reel to yourself, or to other personal equipment.

Depth

A depth of 130 feet is recommended as the limit for normal recreational air diving. Within this limit Hoofer SCUBA divers have additional restrictions upon the maximum depth to which they should dive, dependent upon their diving certification. The specific depth limitations for each level are contained within the current PADI instruction manuals.

There is statistical evidence that decompression illness is more likely to occur on dives deeper than 130 feet, even though decompression tables may be strictly adhered to, and such occurrences are usually serious, with central nervous system involvement. When diving deeper than 130 feet, special care with planning is vital, and recommended deep diving practices should be adhered to. PADI strongly recommends that recreational divers should not undertake dives in excess of the recommended maximum depth limits.

When diving with oxygen-enriched mixtures it is essential that the maximum operating depth for the mixture be adhered to. Failure to do so may have fatal consequences due to the onset of oxygen toxicity.

Distressed Diver

A diver who has allowed sudden, unreasoned fear to replace controlled, appropriate action with uncontrolled, inappropriate action has lost control and has panicked. The panicked diver, fearing drowning, typically struggles to hold his head high above the water, expending tremendous energy.

There are four basic steps to assisting another diver in distress:
1. Establish ample buoyancy
2. Calm the diver
3. Help the diver reestablish breathing control
4. If necessary, assist the diver back to the boat or shore

Distress at sea can range from an extreme form of decompression illness, where life is threatened, to divers being lost on the surface having been swept away by the tide. Procedures to deal with such a range of emergencies are as follows:

Any dive boat at sea requiring Search or Rescue assistance for a missing or overdue diver should use a 'MAYDAY' call if life is in danger. Less serious, but nonetheless urgent requests (e.g. a boat drifting with no engine), may warrant a 'PAN PAN' (Urgency) call. For vessels with Digital Selective Calling (DCS), a DCS alert should be activated on Channel 70 followed by a voice call on Channel 16. For non-DCS equipped vessels the call should be made on Channel 16. If your boat does not carry VHF radio it is sometimes possible to attract the attention of passing vessels who may radio on your behalf.

Flares can be used to attract attention, either from the shore or from other vessels in the area. It is important that flares are not wasted, so only fire them if there is someone likely to see your signal. Several Maritime and Coastguard Agency reports, each year, indicate that some divers leave it too long before raising the alarm. Do not delay too long if you are convinced problems are arising which you cannot control.

For distress at sea, where decompression illness is involved, see Decompression.

Dive Computers

See Computers.

Dive Discipline

Hoofer SCUBA recognizes PADI as it primary Dive Discipline for both instruction of its courses as well as adherence to is diving methods. However, since Hoofer SCUBA is part of a larger, world-class University of Wisconsin system, we have come to recognize the diversity in training agencies that are found throughout the globe. It is for this reason that we accept divers from other certifying agencies into our club, but we ask that these members adhere to our protocols when diving with our club.

It is important to realize however that not all dive agencies are created equally, or have similar rankings like PADI. The following table lists a number of ‘other agency’ qualifications that are considered to be of a similar standard to those of PADI. The table does not attempt to be definitive and only includes the more commonly recognized programs.



It is a rule of Hoofer SCUBA that the Club Divemaster has the authority to suspend a member from diving if dive protocols are not obeyed.
(See Authorized Club Dives)

Dive Leadership

See Authorized Cub Dives, Buddy Diving, and Dive Planning and Organization (below).

Dive Planning and Organization

When dives are taking place, make sure that a responsible person on shore has details of your dive plan and estimated time of return.

Accurate records of diver training, dives and expeditions should be kept at all times.

Dive Tables

See PADI Recreational Dive Planner (RDP)

Diving Flag

As divers, we are expected to share the water with boaters and this sometimes leads to conflict. The purpose of a dive flag is, basically, to warn boats to avoid the area where divers are underwater. Most states require the use of the traditional diver-down flag, some require only the alpha flag, and a few require both. Although federal statutes call for use of the alpha flag, some federal agencies (such as the National Park Service) insist on the traditional flag. Obviously, considerable confusion exists concerning the distinction between the two flags.

Wisconsin State Law
It is unlawful to engage in underwater skin diving or swimming with use of swimming fins outside a marked swim area or beyond 150 feet from shore unless the location of such swimming or diving is marked by a diver's flag.

It is unlawful to scuba dive outside a marked swim area unless the location of the scuba diving is marked by a diver's flag.

Except in case of emergency, anyone engaged in such swimming or diving shall not rise to the surface outside of 50 feet from diver's flag.
The diver's flag shall not be less than 12 inches high and 15 inches long, displaying one diagonal white stripe 3 inches wide on a red background and must be clearly apparent at a distance of 100 yards.
No person diving or swimming shall interfere with someone engaged in fishing. No person shall dive or swim in any established navigation lane.

Except in the case of an emergency, a Wisconsin diver may not surface outside a 50-foot radius from the diver down flag. (Wisconsin boating regulations, page 20, JG LE93.96, PUBL-LE-301 96rev). A motorboat is prohibited on Wisconsin waters from operating within 100 feet of a diver down flag or a swimmer unless the boat is part of the diving operation (Wisconsin boating regulations, page 19, JGLE93.96, PUBL-LE-301 96rev).

Consequently, the prudent diver when operating more than 50 feet from the dive boat should tow a diver down flag and surface within 50 feet of the flag.

Diver Propulsion Vehicles

A Diver Propulsion Vehicle (DPV) is a very effective and effortless way for the diver to cover a large underwater area. By riding, or being dragged along by the DPV, the diver is provided with greater mobility and range for the dive, as well as breathing a reduced amount of the appropriate breathing mixture due to the reduced effort required for motion. Such a reduction in gas consumption may therefore also allow the diver to spend a longer period of time underwater, subject to the personal decompression requirements.

Due to the major risks related to DPVs, the Hoofer SCUBA club suggests not using them unless you have been properly trained or certified to do so. Furthermore, the Hoofer SCUBA club does not allow the use of one DPV per buddy team, and instead recommends that a ratio of one DPV per diver be followed to minimize the aforementioned risks.

Diver Recall Systems

When divers need to be recalled to the surface there are several means available. If they are using SMB's a pre-arranged signal on the line is sufficient.

Drugs

If you are taking prescribed medication of any kind, do not dive unless your physician has given clearance to do so.

Drysuits

There are two main types of drysuit in common use, the membrane type (which requires adequate under garment thermal protection) and foam neoprene drysuits. Each type has different weighting requirements. The buoyancy a drysuit provides cannot be guaranteed to support a diver on the surface safely - the air in the suit is too easily vented when swimming or in rescue situations. For this reason, plus the common sense of having a 'redundant' method of obtaining controlled buoyancy, a buoyancy compensator (BCD) is worn.

Divers can undertake drysuit training during initial training or at any time later in their dive training. Sheltered water/pool training, is essential before progressing to open water. Do not wear excess weight when using a drysuit, wear just sufficient to be neutrally buoyant at 10 feet with a nearly empty cylinder. Divers have experienced problems on ascents because they have used both buoyancy compensator and drysuit to compensate for buoyancy loss, and have not enough hands to operate all the controls plus coping with whatever else they might be carrying.

Drysuited divers should include their method of achieving neutral buoyancy as part of the buddy check and dive brief. A drysuit should not be used as the primary source for buoyancy compensation.