Black Water Diving
When you believe the water is as black as it can get and suddenly the unthinkable happens, it becomes even blacker, you know instantly something has happened, and you are probably not out sport diving. When we talk about black water diving, we are talking about zero visibility, not a little, zero, none. We’re not talking brown water, we are talking black as black can be. Carry a ten thousand candle watt power light and you could not see its beam even if you placed it an inch from your mask.
In public safety diving, where we are most often searching for something on the bottom. Technique and consistency become imperative in our most typical situation – black water diving. Since divers can not see where they are, they have no orientation to where shore is, where they are, where they have been, or where they are going next. Therefore, their diving is tender-directed-tethered-solo diving.
A trained shore or boat based tenders controls his diver’s every movement via a tether line securely attached to the diver. A series of trained signals more often than not becomes their only form of communication, as well as their orientation, and safety – stop, face the line, okay?, left, right, up, down, standby, I’m entangled but I’m okay, I’m okay but need assistance, I’m not okay and need immediate assistance, etc.
In a disoriented environment, the human mind seeks logic, the mind’s eye seeks a center, a focal point that can give it some sort of logical orientation. Similar to flying an airplane in blacked out conditions, the mind’s eye must learn how to trust, an often illogical orientation. Without a direct orientation the mind’s eye cannot allow the brain to focus and thereby trust the information being received.
Divers searching in black water use their mind’s eye in a second fashion, they connect their finger tips, toes, entire body as a big feeling machine. Without visibility divers enhance their other senses to connect what they feel to their mind’s eye. A touch becomes a vision the portion of our brain matter that allows us to visually perceive what we are touching, what is around us, where we are and how it relates to where we have been and are going.
Since divers cannot see, the most effective black water searches are done by tender controlled, tethered, solo divers. Solo divers can focus all their mental attention and physical senses on the search, unlike buddied divers who spend half their attention keeping track of, and staying with, each other. Tethered solo diving with a back-up diver less than 60 seconds away and a 90% ready diver 90 seconds away, is actually safer in black water search operations than buddy or group searches. If one diver gets in trouble with entanglements, entrapment, out-of-air emergencies, fatigue, etc., the buddy is also likely to be in the same or similar situation. In tethered, solo diving, the back-up diver is warm, rested, and ready to go with a full tank.
The tender and diver work together as one. The diver is the tender’s “eyes.” Tenders are the most important people on the site and have the greatest responsibility, Anyone can go underwater and move up, down, right, left, etc. Controlling all of that, and knowing what to do when it is not going perfect is the hard part. The divers’ job is to do as their tender tells them. Tenders can see where the divers are and where the divers are going, by the relationship of the divers’ bubbles, the angle of the tether line, and line movement. The tender monitors the angles of the line and how it relates to references on shore or a series of buoys.
The distance marked tether line is attached to the diver’s harness with a locking carabiner. Keep the line free of loops and knots.The harness is designed for water rescue and tethered diving. The girth strap goes, around the ribs at the level of the solar plexus. If it sat lower it would force the wearer in a vertical position, it could cause discomfort in the unprotected kidney area, and could restrict diaphragm movement resulting in breathing difficulty. The harness needs to have adjustable shoulder straps so the girth can be adjusted to the correct position. Next, the girth strap needs to be closed correctly. Too loose and signals wont be easily felt, too tight and breathing will be restricted. The tender tells the diver to place a hand flat against his solar plexus while taking a large breath. The tender closes the harness adjusting it to fit snugly against the diver’s hand.
The 3/8th inch, flexible, solid braid, floating tether line is attached to the locking carabiner with a figure eight knot. The carabiner is attached to the harness D-ring tether point that sits slightly off center to the solar plexus to help keep the line from ending up between the diver’s legs. With a properly sized harness, a diver can feel signals across a maximum of 150 feet of line in calm water and weather.
? Full-face masks are preferred, but if standard masks are used, make sure to remove snorkels, which will only cause entanglements. Mask straps can be worn under hoods to prevent loss of mask if the mask is dislodged. If a full-face mask is used, an extra half mask should be carried in case the full mask needs to be ditched when the diver must switch to a pony bottle. A quick disconnect block from the mask to the pony bottle is highly recommend to prevent divers from having to remove their full-face masks to access their pony bottle redundant air source. This ability to keep the mask on is important because many searches are conducted in contaminated, cold, or moving water.
? A quick release pony bottle is mandatory for every diver in the operation. It needs to be quick release so that a back-up diver can pass it off to a low-on-air, entangled primary diver. In severe entanglement cases the diver may need to ditch his gear and surface with his pony. For this reason only a quick release block system will work. Octopuses do not belong on public safety dives as they are not a redundant air source, only a secondary mouthpiece. If conventional pony regulators are used, the second stages should be attached in the golden triangle chest area, they should have mud mouthpiece covers and should have the exhaust tees removed. The latter will scoop up mud and can cause entanglements.
? All the diver’s gear should be trim with nothing dangling. Entanglement is the number one problem for public safety divers. Keep all hoses close along the diver’s body. Run the gauges under the diver’s arm between the B.C.D. and his body.
? Back mounted B.C.D.s are not recommended for public safety diving. Most will float an injured or unconscious diver face down, and all will seek to do this when the surfaced diver brings a body back to shore. Avoid B.C.D.s with lots of hooks, rings, bells and whistles, which all increase the risk of entanglement.
? The diver carries at least three cutting tools, preferably shears or wire cutters, in the golden triangle area. Knifes are less effective for cutting fishing line, wire, fish hooks, etc. In blackwater, knives can puncture or cut equipment, and stab divers or bodies. Do not wear cutting tools on a leg where they can cause entanglements and are the furthest point from reach.
? The diver’s weight belt has 10 to 12 inches of webbing beyond the buckle, allowing the diver to catch a loosening weightbelt when a buckle is accidentally opened by debris on the bottom.
? The outside strap and buckle of each fin should be taped to decrease entanglement. Keep the inside strap free if the fin requires strap adjustment. Adjusting or disentangling an outside strap can result in painful leg cramps. Inside straps are easier to reach.
The tender wears a personal flotation device and good gloves, and may be harnessed and tethered back to a secure object if the shore bank is steep or slippery. The end of the diver’s tether line is secured with a nonlocking carabiner and a strap to a nonmoving object. The back-up diver and back-up tender, and the 90% ready diver are in place. A rescue throw rope bag, a contingency pony bottle and full 80 cuft cylinder with a regulator, are placed near the back-up diver’s tender.
As the diver prepares to descend the tender gives a signal of one, (okay) the diver returns the signal, signifying, all is okay for leaving surface. The tender gently controls the line as the diver descends. In moving water, procedures are a little different. As the diver reaches the bottom he responds with a one, signifying he reached the bottom, is comfortable, and is ready to begin searching.
The tender signals right (3) or left (4) telling the diver which direction to begin the search. The diver’s job is to search and maintain a taught line. If there is slack in the line the diver’s job is to take it up, hence if the tender wants the diver to go further out, the tender simply gives more line, at which point the diver takes up the slack and goes further out. If the tender wants the diver to come in, she slowly and gently pulls the diver in. Signals are always returned and always oriented to the diver’s right or left.
If your tenders have trouble figuring out the diver’s right and left, mark the tending gloves with L= 4 on the right hand and R= 3 on the left. This may seem childish however we find people often have trouble with their right and left.
As the diver reaches the turn-around-point at the end of the sweep, the tender signals one, telling the diver to stop and face the line. The diver follows the instruction, taking up any slack that may have been created, and returns the one. The diver’s orientation to the tender and shore is now fixed in his mind’s eye. He now knows which is his left and right, up and down. No matter how dark the water, the diver will have a center point making orientation easy.
As the diver changes direction, the tender brings the diver into the new sweep by taking in the line. Ninety percent of the time, divers are pulled in towards the tender at the end of each sweep, instead of being let out. Divers will search more effectively if they know they are continually working their way home – as their tank pressures decreases, as they become fatigued and possibly frustrated, and as they lose fluids and possibly work towards cold or heat stress.
The amount of line taken in is in direct proportion to the visibility and the size of the object being searched for. In zero visibility-small item situations, the diver is pulled in one to two feet. Searches for large items such as a full size adult bodies allow two to three feet between sweeps.
The back-up diver’s tender draws every move the primary diver makes on a profile slate, using ranges and marked line distances. (see Fig. # ) The diver can give signals to the tender when large objects or entanglement hazards are encountered. The profile
? becomes an underwater map,
? it shows exactly what areas have been searched and what areas still need to be searched,
? and the last known location of the diver in an accidental disconnect situation.
? this also allows for a repetable patern at any time during the diveopperation.
Divers often argue the concept of tender controlled diving, especially in the beginning stages of public safety underwater work. As sport divers they have learned how to be self reliant, and free swimmers. Free swimming is great when you can see where you are going. Underwater compass work is an excellent skill when you have three advantages. One, you can see your compass, and a little bit of where you are going. Two, when you do not have to make eight to ten exact patterns, one hundred feet long by two to three feet wide. Three, when you do not need both hands to search with or protect yourself from unseen debris. We are for the most part an industry of sport divers, who often reluctantly embrace growth or change even when the need is blatant.
Technical and public safety divers are exploring new territories every day, every dive. Making it work better and safer is what it is all about. In the public safety sector, signals are everything – the diver’s direction and safety. Contingency signals are also very important. I’m entangled but can get myself out, I am OK but require a little help, I am in big trouble and need help now, are three important contingency signals. A single I need help signal can actually be dangerous, yet unfortunately that is all most dive teams have.
One of the things that we work on adamantly for all black water divers is the diver rescue concept. The contingency plan needs to be practiced redundantly. It cannot be a procedure designed in a table-top disucssion, written into the standard operating guidlines, and never taken further from there.