A Guide to Good-Sense Diving

We divers are a fortunate lot. We can enjoy first hand a part of the environment that most non-divers experience only vicariously — through television, movie or computer screens. We each have our own special motivations for diving, but one thing is common: we love our recreation.

Each year new and experienced divers alike from all over the world make millions of enjoyable scuba dives; and for the vast majority of the time, we make these dives without incident or injury. This is because as certified divers, we take our fun seriously: we have taken the time to learn safety guidelines to become conscientious and responsible divers, so we can keep on diving. And we talk about our dives, learning from our own — and others’ — experiences.

New divers can learn quite a few “good-sense” tips from other divers. This helps to prevent injuries and mishaps, and it illustrates the camaraderie of teamwork so widespread among divers.

Not all good-sense tips are scuba safety rules or guidelines, but they generally relate to basic principles every diver should know. DAN’s staff members have put together a collection of their good-sense tips based on their insights in scuba diving over their many collective years of experience.


If you’ve been diving for a while, or if you’ve just learned how to dive, there’s a lot to learn — and remember — about diving. You can start by remembering that each dive should be a SAFE DIVE, directly related to:

• Self-reliance

• Attitude

• Fitness

• Experience

• Diving skills

• Involvement

• Variety

• Equipment

Be Self-Reliant

Diving, like life itself, is an experience best shared. You are responsible for your own dive experience. Self-reliance is a skill your safety depends upon, topside or underwater. While divers are trained to use the buddy system to improve safety and reduce risk, you should be able to make informed decisions about your safety during any dive, without relying on someone else to think for you.

Following a dive leader or your buddy into an environment, condition or depth that you are not trained for, not comfortable in or is outside your experience is an invitation to disaster. Being self-reliant means knowing your limits — and those of your equipment.

• Take care of your equipment. Keep it properly serviced and maintained. Do not modify your equipment outside of the manufacturer’s original design.

• Check it out. Always use a checklist when packing equipment for a dive outing. If you get to the dive site and are missing an essential piece of equipment, consider renting or buying a similar model. If you’re not comfortable with these options, you may want to cancel the dive.

• Suit yourself. You need to wear all of the required equipment for the type of dive you’re making.

• Stop, Breathe, Think, Act. If you’re experiencing a problem underwater remember this: if you’re still breathing, you have some time to deal with the problem. Bolting for the surface is dangerous.

• Pause and refresh yourself. If you haven’t been diving for awhile (six months or longer), attend a refresher course.

• Learn to say NO. “A ‘good’ diver is not the person with the most gear, or the one who dives the deepest,” says DAN Medic Eric Schinazi. “It’s the one who can make a mature decision that they should not make a dive.”

• An ancillary maxim is that good buddies respect this decision.

Have The Right Attitude

• Assess your goals. This is critical for safe diving. What are your motivations to dive? Your buddy’s? Buddies with different attitudes or goals for a given dive are likely to be incompatible. A diver who seeks adventure or is out to set personal records will be at odds with a diver who hopes to observe and photograph underwater marine life.

• Assess yourself. Are you psychologically ready to do the dive? Are any of the dive’s prospects causing you stress? If they are, talk about it with your buddy and work to resolve them prior to entering the water— you’ll find your stress levels dropping once you’ve begun talking about your concerns. Don’t let anyone dismiss your feeling as insignificant or unimportant.

• Don’t dive if you feel pressured. Remember, if you’re not having fun, stop diving.

Be Fit

• Check yourself. Checking and maintaining your equipment is a good-sense tip, but how many divers stop to check their personal health and fitness before diving? Fitness for diving adds to the comfort and enjoyment of each dive.

• Think fast. Dive conditions can change quickly underwater as tides and currents shift. You may be swimming in from a dive and suddenly get caught in a rip current; or be along a reef when a sudden current forces you down the wall. While these occurrences are unexpected and rare, you need to have the fitness and resources to exit safely.

• Clear signals. If you’re diving in areas where currents are common, carry a signaling device like a flare, whistle or safety tube to alert people on the boat or shore if you encounter any difficulty.

• Nothing to sneeze at. Dive only when you’re healthy and your ears and sinuses are clear. The most common diving injury is ear barotrauma, often caused by congestion. Because of the time and money involved in a dive trip, many divers ignore the early stages of a cold or congestion and dive with the assistance of over-the-counter medications. When the medications wear off (sometimes this happens at depth), your body’s ability to manage the effects of changing pressure is limited, and barotrauma may result.

• Be heart-smart. Cardiovascular disease is the most common cause of diver death in divers over the age of 40. If you’re over 40, have an annual physical with a physician knowledgeable in diving medicine. A cardiac stress test may also be a beneficial preventative measure for you.

• Bag it. If you’re fatigued, sick or just not feeling well, don’t dive. Illness and injury increases your risk of decompression illness (DCI), and your performance underwater will suffer, too. Dehydration may also contribute to DCI. Hot and humid climates, the hot sun, dry compressed air from your scuba cylinders and immersion diuresis all help to dehydrate you. When you’re traveling and diving, make sure you drink more than eight glasses of water a day.

• Know your limits. Overall physical fitness is important, but knowing your physical limits may be more so. When you begin to feel overexerted or tired, rest and discontinue diving until your energy level has returned. Watch for signs of overexertion in your buddy, too. While you can’t necessarily control the tides and currents, you can improve your fitness and your preparedness for those environmental changes.

Have The Right Experience Level

• Be careful. It’s paramount to your safety and enjoyment. If you’ve never been on a dive to 100 feet / 30.4 meters or if you’ve never made a dive at night, consider buddying up with an experienced diver or taking a course with a diving instructor to expand your comfort zone. If you feel uncomfortable about the dive, it may be because you feel you’re not ready.

• Proceed with caution. Slowly extend your diving experiences. If you’ve been diving to 60 feet / 18.2 meters, try a dive to 80 feet / 24.3 meters. For your first night dive, go at twilight. Also, make sure your buddy has the needed experience.

• Take a course. The best way to extend your diving range is to take a diving course for the environment or experience you want. Want to learn how to wreck dive? Sign up for the course so you’ll learn about the planning, hazards and techniques associated with it. While experience is a good teacher, a teacher with good experience can maximize your understanding of the skills involved in the specialized diving activities you pursue. Plus, you’ll be able to document your experience with a certification card so you can pursue your interests further.

Practice Your Diving Skills

• Practice makes (almost) perfect. Diving skills can get rusty through long layoffs between dives, especially for new divers. When was the last time you practiced removing your mask underwater? How about out-of-air drills or removing your weight belt underwater? It was probably during your first scuba class. How long ago was that?

• The Big Four. Four primary diving skills need to maintained: mask skills, buoyancy skills, emergency skills and general diving skills such as swimming and equipment handling. One of the best times to practice these skills is during your safety stop.

• Weighty matters. To determine the amount of weight you should dive with, you should be neutrally buoyant during your 15-foot / 5-meter safety stop at the end of your dive with between 300-500 psi / 20-34 bar in your tank and no air in your buoyancy control device (BCD). If you remain motionless and you sink, you’re overweighted. If you start floating to the surface, you’re underweighted. Adjust your weight on the next dive accordingly.

• Review. In your pre-dive plan, review out-of-air procedures with your buddy and practice them at the end of your dive. During your safety stop, or prior to descent, locate and breathe from your buddy’s alternate air source. Practice buddy breathing if your buddy doesn’t have one. Remove your mask and replace it.

• Learn to love snorkeling. Many new diver students haven’t had much experience or skill in snorkeling. If you become completely comfortable in open water, regardless of depth or whether you can see the bottom with just mask, fins, and snorkel, you’ll have much better odds of being a relaxed, safe scuba diver.

• Taking a few moments at the end of your dive to refine and master these basic skills will mean that in the unlikely event that you’ll need to use them in an emergency, you’ll be ready.

Get Involved

• Make plans. Getting involved in the local community is a great way to meet new people and find out more about the local diving scene. Find a local dive club or dive center and sign up for meetings, programs and courses. This provides for excellent opportunities to find a buddy, locate a great lobster hole or wreck and socialize with other divers with similar interests.

• Make friends. When you become active in the local diving community, you also get the opportunity to find a diving mentor. The friendship and camaraderie of a group of divers is one of the many reasons why people keep diving.

• Says DAN Director of Special Projects Chris Wachholz, “As a hesitant 14-year-old diver in 1971, I would never have learned to love the sport without the advice, security and role model of (not always) patient, older and more experienced divers.

• “I believe this advice goes to experienced divers as well, who should give something back to the sport by being a mentor and help another person become a lifelong enthusiast.”

Savor The Variety

The spice of diving. From the wrecks off the coast of North Carolina or Truk (Chuuk) Lagoon, to the kelp forests in California waters, lobstering in Florida, or capturing your underwater moments on the Great Barrier Reef, off the coast of Africa or the Middle East, diving has something for everyone. One of the greatest ways to keep your passion for diving is to explore your underwater world. Traveling the world and experiencing new cultures is one of the most fun ways to keep active.

However, with each new experience comes caution. It is vital that you are familiar with your environment or are under supervision by an experienced dive guide. “The variety of interesting diving experiences is matched by the variety of potential hazards,” says Barry Shuster, DAN’s Director of Marketing. “Awareness of local currents, underwater topographic formations, marine life and proper entry and exit techniques can save you a great deal of grief.”

Equip Yourself

Take three. There are three primary equipment considerations for divers:

• Do you have all the necessary equipment to conduct the dive? Do you have a depth gauge? A timing device? An alternate air source? All of these items are critical for dive safety. If you don’t have a depth gauge or timing device, you’ll be unable to judge your ascent rate and plan your dives to be within the no-decompression limits.

• Do you know how to use and maintain your gear? Many new divers (and some experienced ones) are unfamiliar with equipment maintenance procedures. Rinse and soak your equipment in fresh water and let air dry. Pay particular attention to your regulator. Look for signs of wear (See “Dusting Off Your Gear”, page 32) and check the hoses for leaks and cracking. Take an equipment maintenance course for more information on gear maintenance.

• Can you get to your equipment? Is your alternate air source in your BCD pocket, or is it readily available? Is your equipment properly sized for you? Many divers wonder why neoprene shrinks year after year. (It’s not the suit!) Your equipment is a tool to let you safely explore the undersea world. Take care of it, and it will take care of you.

By making every dive a SAFE DIVE, you’ll expand your skills and knowledge — and have more fun. You’ll also help your fellow divers by demonstrating the steps of safe diving.

AAUS Recommendations

The American Association of Underwater Sciences (AAUS) makes these recommendations for general dive safety and dive computer use:

• All divers relying on dive computers to plan dives and indicate or determine decompression status must have their own unit.

• On any given dive, both divers in the buddy pair must follow the most conservative dive computer.

• If the dive computer fails at any time during the dive, the dive must be terminated, and appropriate surfacing procedures should be initiated immediately.

• Divers should not dive for 24 hours before activating a dive computer to use it to control their diving.

• Once a dive computer is in use, it must not be switched off until it indicates complete outgassing has occurred or 24 hours have elapsed (whichever comes first), or if no more dives are planned over the next few days.

• When using a dive computer, nonemergent ascents are to be at the rate(s) specified for the table, or by the make and model of dive computer being used.

• Ascent rates shall not exceed 60 feet of sea water (fsw) / 18 meters of sea water (msw) per minute.

• A stop in the 10- to 30-fsw / 3- to 9-msw zone for three to five minutes is recommended on every dive.

• Repetitive and multilevel diving procedures should start the dive, or the series of dives, at the maximum planned depth, followed by subsequent dives of shallower exposures.

• Multiple deep dives should be avoided.

• Breathing 100 percent oxygen above water is preferred to in-water air procedures for omitted decompression.

• It is recommended that divers’ attention be directed to emphasis on the ancillary factors to decompression risk such as: fitness to dive, adequate rest, hydration, body weight, age, and especially rate of ascent — which should not be more than 60 feet / 18 meters per minute.

• Divers are encouraged to learn and remember the signs and symptoms of decompression illness and report them promptly. This enables them to receive effective treatment as rapidly as possible and helps prevent residual injury later on.

• Breathing oxygen on the surface whenever possible via a demand regulator mask system (to ensure the highest percentage of oxygen to the patient) is recommended while awaiting treatment if decompression illness is suspected. The use of 100 percent oxygen in the water while awaiting treatment is not recommended.



Actual table or computer limits do not necessarily constitute a boundary between “bends” or “no-bends.” The safety decisions you make should be based upon current suggested safety guidelines for diving and your own unique circumstances while diving.

Be prepared to modify these guidelines to accommodate personal physiological factors affected by your activities before, during and after diving. DAN’ s Dr. Peter Bennett recommends divers perform no strenuous exercise 24 hours before or 12 hours after any dive, to help prevent decompression illness.

• Keep to the limits — Stay well within the guidelines of the table or computer you’re using, and allow an appropriate surface interval between dives.

• Do your deepest dive first.

• Be prepared to modify your dive plan for unanticipated factors such as exertion, cold or depth.

• Be well — Make sure you’re rested, healthy, well hydrated and well-nourished prior to your diving activities. Avoid alcohol before and between dives.

• Equalize — Begin equalizing before your head submerges and continue to equalize frequently during descent.

• Descend feet first — This slows your descent some and makes it easier to equalize your ears.

• Ascend slowly — Dr. Bennett recommends ascending at the rate of 30 feet / 9.1 meters per minute.

• Make a safety stop — for three to five minutes at 10-15 feet / 3-4.5 meters on all dives.


• Buddy Up. Select a partner who will enhance your enjoyment and safety. A good buddy is someone whose skills, abilities and attitude are complementary with your own.

• Communication. Prior to your dive, make sure you’re both on the same dive plan
. Discuss the maximum depth, maximum bottom time and minimum air supply to terminate the dive. Review basic hand signals and identify any pet or regional hand signals you may use.

• Weathering it. When you get to your dive site, assess the physical situation. What are the tides like? What type of entry will you be making? What’s the weather like now? Will it change, according to reports? Does it look like “your kind of dive day,” or should you think about sitting this one out? Discuss this with your buddy.

• Equipment Familiarization. After checking out your own equipment, take a few minutes to familiarize yourself with the placement and operation of your buddy’s equipment. This a good learning experience, and it could help manage a later problem.

• The Buddy Check. While suiting- and gearing up, conduct a pre-dive safety check on yourself and your buddy, and correct any problems you find. Minor inconveniences can add up to significant problems if not resolved early. Hair stuck under your mask skirt can be stressful if it means having to clear your mask every couple of minutes.

• The What Ifs. Review what you and your buddy would do if:

o you were separated underwater;

o you went deeper or stayed longer than planned;

o you ran out of air underwater;

o you got behind the dive boat and downstream in the current;

o you experienced an equipment problem (e.g., loose tank band).

• If you were to run low on air or find you’re completely out of air, do you dive close enough to your buddy that you could quickly solve your problem? You may want to dive with a pony bottle or Spare Air™. While you’ll still need to signal your buddy, you’ll be able to surface without assistance.

• You should also practice making emergency ascents and removing and replacing your equipment in the water. With neoprene gloves on, it can be difficult to locate your weight belt and replace it if you needed to. You should be able to locate by touch every piece of your equipment quickly — and that of your buddy’s. If you don’t know how to handle a particular problem, ask your divemaster.

• Stay together. The “same day / same ocean” philosophy does not constitute a buddy team.

• Always dive your plan. A few well-spent minutes topside prior to the dive will prepare you and your buddy for the rewards that come with a safe and enjoyable dive.


• Establish how much air you will need to make the dive. You need a continuous circuit of air from your entry until you exit the water, with some left in reserve “just in case.”

• Check your pressure gauge. As part of your annual equipment overhaul, have your pressure gauge checked for accuracy. If the equipment is not yours, check it against a known tank pressure, and after the check make sure the needle returns to zero.

• Monitor your air supply. And check your buddy’s regularly during the dive, so there are no surprises. Air management involves two air supplies, not just one.

• Establish when to “call the dive.” Have a pre-determined point at which you or your buddy call the dive due to low air. Once the signal is given, begin your ascent.

• Note special circumstances. Use the “Rule of Thirds” with your air consumption, a dependable procedure used by cave- wreck- and under-ice divers. Use one-third of your air supply to go under, one-third to come up; and keep one-third in reserve. This also helps with ensuring you have enough air if, for example, you’re biding your time in an attempt to surface in the midst of holiday boaters or another “virtual” overhead environment.

• Surface with 300-500 psi / 20-34 bar. Good advice from Dr. Bennett, this could help you in a worst-case scenario — or for that “just in case” incident.


There’s nothing wrong with saying, “Hey, I’ve never done this;” or “I’ve never used this piece of equipment before. I need some help.”

• Take it easy— if you’re not having fun or you don’t feel good about it, don’t do it! And pay attention to your bottom references. “If it’s my first time on a particular dive,” says DAN Director of Operations Dan Orr, “I start the dive close to the shore and follow the contours down to the bottom. On the other hand, if I start the dive away from the shore, I use a descent / ascent line or anchor line.”

• This is especially important for divers experiencing cold water, the buoyancy change caused by the compression of their wetsuit or drysuit, and limited visibility for the first time.

• In addition, you can:

o Get additional training — Your certification means that at the time you receive it you are qualified for the same diving conditions and environment in which you were trained, says DAN Medic Bruce Delphia. Open-water divers are not trained to dive below 60 feet / 18.2 meters. Beyond this depth in sport diving is the depth at which all subsequent dives are considered DEEP.

o Dive with the locals — it provides you with an opportunity to establish new friendships and buddy contacts, and you can pick their collective brains about the best places to go.

o Practice your skills — this enables you to respond more quickly and smoothly to any challenges when you dive.

— By Dan Orr and Bill Clendenen, with contributions from Dr. Peter Bennett, Joel Dovenbarger, Chris Wachholz, Barry Shuster, Bruce Delphia, Eric Schinazi and Renée Westerfield.


For more information on any of these points, ask your dive instructor. Another good way to improve upon your basic dive knowledge is to read up on diving, with texts such as:

• Alert Diver

• The Best of Alert Diver

• DAN’s Dive and Travel Medical Guide

• A Medical Guide to Hazardous Marine Life, by Paul Auerbach, M.D., M.S.

• Diving Physiology in Plain English, by Jolie Bookspan, Ph.D.

— and a wide variety of related publications available from DAN.

And take every opportunity you can to get back in the water and practice your skills. The more you dive, the more practical experience you gain — and the greater pleasures you will have when you go down under the waves.