Night diving offers experiences different from conventional daytime diving. Extensive preparation should be undertaken before conducting a night dive. Special vision-enhancing and safety equipment should be utilized by the diver.
For most divers, night diving in warm water is enjoyed on a tropical vacation. You’ll get hooked because it is great fun. At a resort someone else does all the planning and supervises the nocturnal underwater sojourn. Once home, in more temperate waters, you will be on your own to plan and execute night dives. The key to safe, fun night dives is to plan ahead. The following are a few things to consider before jumping in for a temperate water night dive:
- Is your thermal protection adequate? (Psychologically, water seems colder in the dark.)
- If diving from shore, is your entry/exit point lighted/marked?
- Can you locate the intended off-shore site at night?
- Do you have a reliable underwater light and a back-up?
- Have you recently been at the dive site in daylight?
- Have you notified a nondiver of your dive and developed an action plan for them to initiate if you do not return on time?
- Are you comfortable with very limited visibility?
- Is your buddy a leader, follower or of equal skill and comfort level for the planned dive? Is his/her ability level OK with you?
- If you plan on boat diving, do you have a nondiver to stay on board during the dive?
- Have you checked your equipment and know it is in top notch condition, pre-adjusted and ready to don?
Night diving is an advanced diving challenge. It stretches your personal boundaries of underwater comfort and enhances your pre-dive planning skills. Night diving offers great fun – the undersea life changes when the sun sets. Just like the forests have one visible set of animals during daylight and a different selection at night, so does the aqua world.
Lobsters and abalone are out foraging under the cover of darkness and are easier to catch – in season, of course. Elusive freshwater Walleye are impossible to find in lakes during the day but can be seen at night, seemingly asleep in patches of aquatic grass. And, like small children exploring in the woods, it is great adult fun to survey a reef and see what surprises await you. Since divers are generally creatures of the day, it is a little spooky and adventurous swimming around at night. That’s part of the natural high of facing the unknown.
Night Diving Equipment
To have a safe and enjoyable night dive, you will need some additional equipment. The most obvious is a dive light. These can range from flashlights for less than $20 to larger lights with six volt or multiple battery power sources. These larger lights have a handle separate from the barrel and are powered by dry cell or rechargeable batteries. This style light ranges from $20 to $100, depending upon the case material, power source and type of bulb assembly. There is no one “right” light. It all depends on the cost, location and activities planned for your night dives. You may even want to choose a secondary light that is small enough to take on day dives for hole peeking and color enhancement, using a larger model as your primary light.
The one or two light debate could go on for pages but this author’s opinion is that common sense ought to prevail. If you are clear, warm water, group boat diving, a la Caribbean resort style, then one “average” light per diver is common practice. On the other hand, if two divers are night diving offshore, each ought to take two of the most powerful, rugged, reliable lights he or she can buy. For ultra-advanced nighttime wreck or deep diving, also consider wearing an arm strobe for emergency signaling. The conventional wisdom from the training agencies is to take two light sources.
Features to consider when selecting a light:
- Narrow or wide beam?
- How heavy is it on land and how far is your hike?
- Does it float and is that an advantage/disadvantage where you dive?
- Can you turn the switch on/off easily with one gloved hand? Too easily? Can the switch get bumped on accidentally?
- Is it durable enough for your typical dive environment?
- How often will you night dive? Dry cell batteries are less expensive if you don’t use the light often.
- If most of your night dives are made while traveling, which will be easier, more available, cheaper – alkaline cells or rechargeable batteries?
- Does the light have a means of attaching a wrist lanyard?
- How bright is the light – does it seem bright enough for the color and clarity of water where you usually dive?
- Does the O-ring seal appear to stay in place when opening the light or will it be easy to lose or crimp (and flood) when changing batteries?
- What is the depth limit?
- What is the manufacturer’s warranty period?
- Does your local dive store stock the common replacement parts?
- What lights do your buddies use? Would they repurchase the same type?
Chemical lightsticks are great for night diving – but not for your primary viewing light source. Tie a lightstick to your tank valve to aid a divemaster or your buddy in locating you. You attach it to your tank so it is easy for others to see and the glow is out of your eyes. Chemical lights are short, plastic tubes that contain two chemicals. When you bend the light it cracks an inner ampule, allowing the chemicals to mix and react and producing a glow that lasts four to six hours. These inexpensive lights are waterproof, pressure proof and heatless. There is a high intensity model that only lasts about 30 minutes, so read the label carefully before purchasing.
Waterproof strobe lights are available. The intermittent flashing of the xenon light allows for an extended running time but would drive you crazy as a primary dive light. Strobes are best used for emergency signaling underwater or as surface markers.
Surface lights are another consideration. If you need to exit the water at a certain place, it is a good idea to leave a light marker on shore. A Coleman type lantern, a roadside type warning beacon (look in the yellow pages under construction equipment for where to purchase) or a fluorescent roadside emergency light are good choices. Shore lights have some inherent problems in populated areas. Residents don’t like bright lights in their bedroom windows. Opportunists seize the chance to recover a “lost” light. Divers count on using the light to find their exit point and when the light fails or walks off, the divers don’t know where to exit.
The solutions are to mark your light with “Do Not Remove – Divers Underwater,” have a beach-watch buddy or, before you descend, look for shore landmarks to relocate the exit point. Select land and light marks that won’t move or turn off, e.g., don’t use someone’s porch light for a marker. If you are diving from a boat, plan to leave the deck lights on or consider hanging a waterproof lamp overboard but realize the lights may attract critters such as bugs, Flying Fish or Squid.
If you are diving in navigable waters, be careful that the brightness and placement of your shore light doesn’t create a false navigation aid that might beach a boat.
All your regular gear is fine for night diving – tank, regulator with an extra second stage, submersible pressure gauge and low pressure BC inflator, buoyancy compensator, wetsuit (for thermal protection), depth gauge, watch/timer, compass, gloves, mask, fins, snorkel, weightbelt and knife. Check your equipment for a streamlined profile. Things that catch on a night dive conjure up images of sea creatures latching on!
Optional equipment that might aid your enjoyment and safety includes a buddy line, slate or an ascent/descent line with surface float. Some states require a dive flag be flown, even for night diving. Many night divers take a whistle for surface signaling.
Night Diving Procedures
The diving part of night diving is the same as day diving. The real difference is in the preparation. Plan your dive in greater detail than you typically would. Only night dive a reef where you have been during the day so you know the lay of the land. Try to optimize conditions – calm, clean water on starry, cloudless nights with a full moon is the ideal. Check the tide tables to dive at slack tide.
Second, find a place with sufficient light to gear up so you’re confident your gear is correctly assembled, in good working order and that you can make a thorough buddy check. Review hand and light signals with your buddy. Remember to position the shore beacon before you gear up. If you dress on a sandy beach, use a ground cloth to avoid losing small items. Third, get ready for adventure.
Night diving is equal parts eerie and exhilarating. If you catch yourself breathing a little fast or shallow, make a conscious effort to slow down. Calm down by taking control of your breathing pattern. Adjust your buoyancy to neutral and r-e-l-a-x.
Snorkel to the descent point, recheck your shore or boat light for distance and direction. Descend feet first to maintain eye contact with your buddy and begin to enjoy the surrounding marine riot. Aim your light toward the bottom to help judge distance and provide a directional orientation. Control your light so the beam does not shine in your buddy’s eyes. The micromarine life will dance before your light, dynoflagellates show off with light flashes as your movements disturb them mid-water and as you settle on the bottom, a surprised ray or flatfish may rise out of the sand.
As your sightseeing trip continues, use distinctive reef formations and compass bearings to dive your plan. Be aware of gradual depth changes, since you’ve lost the usual light-related clues of increasing depth. Check your air supply frequently and be vigilant about keeping track of your buddy. The time will fly – much like on your early scuba dives. Everything is so wondrous and new that bottom time disappears in what seems like a few moments.
At the completion of the dive, surface and return to the shore or boat. If shore exiting, spend long enough outside the surfline to be confident the wave pattern is similar to what it was when you entered. Head for your shore light. Once high and dry, respect the still of the night with quiet voices. Take a few moments to reflect and share with your buddy the joys of the experience. Savor the unique moments you’ve just enjoyed.
Night Diving Guidelines
- Dive at a familiar site.
- Select a protected site with easy access, shallower depths and a reef formation to follow.
- Be confident in your diving skills.
- Be in appropriate physical condition for the dive, including free of the influence of drugs or alcohol.
- Know you are not claustrophobic.
- Select and use appropriate primary and secondary lights.
- Pre-check your equipment in a well lit place and assemble as much of your gear in advance as possible.
- Mark your exit point, whether a boat or on shore, with a reliable light.
- Dive with a buddy.
- Notify a nondiver of your intended dive time, place and activity. Notify that nondiver as soon as you complete the dive.