(click on question to see the answer)
What should a Public Safety Diver look for in a buoyancy compensator? …
- Something with all or some of the following features:
* Jacket style: Avoid backmounted BCs as they will force you face down if you are carrying a body on the surface, and will do the same if you become unconscious. Horsecollar BCs make it very difficult to properly transport a drowned victim on the surface.
* Plenty of lift: At least 35 lbs. Remember you may be supporting the negative weight of an adult.
* NO integrated weight system: Weight belts should be removed before any other piece of gear including mask, regulator, or fins.
* Quick-release shoulder straps: A plus for one-handed BC removal.
* Extra large shoulder and chest buckles: For quick, one-handed opening even when your hands are cold, you are carrying a body, and/or are wearing mittens.
* Heavy duty construction: Able to withstand continual contact with a debris-filled bottom.
* Trim: No clips attached to the BC, avoid extra rings, and anything that increases the risk for entanglement. Tools should be carried on the harness, not the BCD.
* Multiple Pockets: Easily accessible for cutting tools, marker buoy, window punch, etc.
* Hard backpack: Soft packs were designed for easy travel in a suitcase not for diving. Hard packs keep the tank in one place on your body. Soft packs offer little support so tank moves up, down, and side to side. This movement makes diving less comfortable, makes for poor buoyancy control, and increases the chance of entanglement. Each of these problems is compounded when a pony bottle is added.
* Make sure: It does not cover a drysuit inflator valve, weightbelt release or harness tether point.
* Bright color: Such as orange, allowing shore personnel to better see a surfaced diver.
* Built-in quick release pony bottle pocket: This will save time and money.
The Lifeguard Systems BCD meets all these requirements and more!
What type and size of line is best for ice and water operations? …
- 3/8″ (9mm) highly flexible, floating line with some stretch is best for ice/water rescue/recovery operations not requiring low or high angle rigging.
* It allows the best accuracy and speed of throw rope deployment.
* Small diameter is too difficult to handle. Larger is too heavy and creates far more drag.
* Expensive rescue line is a waste of money and too heavy for ice/water rescue.
* Semi-static and static line means the person at the end of the rope takes all the abuse when pulled into a rock or entanglement. Ask us why line with a little more stretch is better for anchoring, passing off to a fastwater victim, ice rescue, and more.
* It is easiest to pack in bags, which is the most effective way to store up to 300′ of line.
* It is very easy to tie knots with.
Line with 1500 lb. tensile strength will do the job well.
Can I use a rappelling harness for water/ice operations or diving? …
- No, not unless rappelling is part of the rescue operation. Rappelling harnesses have tether points low on the torso, putting the person in a vertical position. In the water or ice, we need to be in a horizontal position for a variety of reasons. Low tether points make extrication from an ice hole very difficult or impossible, can result in drowning, and are completely wrong for divers.
Do I want leg straps for my harness?…
- NO, we do not recommend them for most types of operation, and do not use them for diving.
* A properly fitted, half-body water harness will stay on the wearer in even extreme conditions.
* Leg straps can cause discomfort, decreased blood flow to the legs, and restriction of overall movement, all of which can be safety hazards.
* A harness with leg straps takes longer to don and requires more training on the part of both the tender and rescuer/diver.
* Least important, leg straps increase the cost of the harness.
Should I wear an octopus as a Public Safety Diver?…
- NO! Octopuses are for shallow water, high visibility, buddy, sport diving. They are NOT a true alternate air source and do absolutely nothing for you if you use up your air. An octopus is only a second mouthpiece. It is strictly for a buddy, not for you. Public Safety Divers, deepdiver, ice divers, and low/no visibility divers belong in quick-release pony bottles, which supply a true alternate gas source and can be passed off to an entangled diver.
An octopus not only does nothing for you, it actually becomes a safety hazard when it causes entanglements. In ice diving, an octopus significantly increases the chance of freeflowing, which is a definite hazard.
Why do I need a contingency strap?…
- The use of a contingency strap allows contingency divers to descend to the primary diver without pulling on the primary diver’s tether line. This is important because pulling on the line could increase the severity of an entanglement problem and could drive a fish hook deeper in. The contingency strap also allows the contingency diver to have two hands free without the possibility of losing the primary diver’s tether line. The strap should have enough length to allow some maneuverability around the primary diver, but not enough length to allow it to reach the primary diver’s throat if the contingency diver attempts to rise and reach behind the primary diver. The strap has a quick release buckle in it’s center that allows the contingency diver to disconnect from the primary diver’s tether line and work behind the primary diver.
We use full face masks, pony bottles, and blocks and dive in contaminated water. If our pony bottle runs out of air what can we do to access more air without removing our full face masks and exposing ourselves to contaminated water?…
- Butch designed the concept and functioning of the RSV-1 second breath block for that very purpose. The pony intermediate pressure hose is connected to the block with a quick-release connection such as a Scubapro™ Air II hose. If the pony runs dry a contingency bottle with the same hose on its regulator can be connected in. This does take practice though. Do not expect to do it without repetitive, stress-loaded training.
Is there really a difference in total air consumption when using an AGA as opposed to a conventional regulator?…
- Yes. We have found that divers using positive pressure AGA masks uses 10 to 20 percent more air. Demand AGA users can use about 10 percent more air.
I need an opinion on FFM comm systems. I initially thought to go with a hard wired rope system, due to needing a rope anyway on search patterns, then thought maybe a wireless would be better, because in a pinch, we could use any rope?…
- That is a question many teams face. We recommend hardwire comms for teams who dive tethered. Wireless comms can be a real annoyance sometimes. OTS makes the best comm. Systems out there and even with their wireless comms we find more problems than with their hardwire systems. When wireless comms work they are great, but they are more of a headache more often. Hardwire if taken care of properly, and if it is an OTS system, will almost never fail. It takes seconds to set up. It is not another thing to worry about because it becomes the tether line, and all the tender does it connect the batteries, don the headset and turn on the box clipped to her belt or backpack. Wireless uses a surface station. Tenders need to be very mobile. One minute they may be walking their diver through thick brush, they may be belaying their diver down a steep embankment and then are themselves belayed by someone else, they may have to work on a small boat, or they may need to be lying on their stomach on thin ice. How can you do all that with a surface station? How do you perform a dock walk (box search, pier walk) with a surface station? You literally need someone walking with the tender to hold the surface station box. What are the advantages to a surface station? Yes you can plug in more divers, but why would you want to do that? Each diver and tender are a pair. We don’t have tenders in charge of more than one diver. That is typically less efficient and not as safe for low/zero visibility operations. We don’t want the speaker box used to allow anyone near the box to hear the diver. The communication between the diver and tender is kept between the diver and the tender so the diver has the confidence and trust that he or she can say anything to the tender, such as “I’m a little spooked, I didn’t thoroughly search a barrel I found on the last half of the last sweep because it gave me the heebeejeebies, I want to do that over…” The tender can relay to the dive coordinator anything that the dive coordinator needs to hear. We don’t ever want two people talking to a diver at the same time. If you want two divers to talk to each other than can be done with hardwire so wireless is not necessary for that. In regards to grabbing any rope in a pinch – it will take longer to set up the wireless comm than it will to setup and use the hardwire comm, so saving time/effort is not an advantage of wireless. Push to talk is typically more common with wireless systems. That is not the greatest. We prefer VOX. No need to push, just talk. Keep both hands free for searching, saving yourself, or saving the primary diver. We recommend a simple, easy to use, very dependable, very mobile, VOX (voice activated) with a simple tender headset and MK 7 or the newer version.
What can I do if my AGA leaks?…
- You need to ensure the mask is donned correctly and must be sealed against the skin or a latex hood. It will not seal (properly) against a neoprene hood. When donning the mask, you must ensure all the straps start at their full length, then put your chin in first or ensure your chin is seated in the chin pocket. Then Pull the straps BACK (towards the back of the head) on the chin straps then the temple and then just lightly snug the top. The mask will fit in this manner for about 85% of the people. If you have a very narrow face or a very wide or large face you will need some modification.
The next step is the surgical tubing or vinyl tubing. If one size is not large enough you need to go up to the next size. The length is 21 1/2″ and
you start and finish the installation in the chin area. This nickel wire or coat hanger is inserted through the center to keep it in place.
When installing the surgical or Vinyl tubing fix, stiff nickel wire is best as it will not corrode. The next best is heavy copper wire and if you have
nothing else, heavy coat hanger will suffice. This wire inserted into the tubing acts as a memory feature and holds the shape of the tubing to the
mask. If it is not installed, the tubing may scoot out from behind the mask seal during the dive. The vinyl tubing and heavy copper wire can be purchased from any hardware store. Answer courtesy of Tim Chapman – Ocean Technology Systems
Some additional thoughts from LGS:
The demand mask is demand, not positive pressure, so you will not have the same kind of air leak. You may want to try a demand mask instead. A positive pressure mask, as we learned from John Hott of OTS, only provides a one inch column of air in the mask. If that doesn’t mean much to you, then go demand.
If you have nothing other than a neoprene hood you can try two things – turn it inside out. This may put rubber, instead of the lycra covering on the outside, and will put the smooth part of the seams on the outside. Then try to have the mask seal either fully on the hood or fully off the hood. Half and half wont cut it. This may mean you have to cut the hood’s face opening a bit larger. If this doesn’t work then purchase a hood designed for full face masks. Make sure to have hood vents.
Just as bigger is not always better, tighter is not always better. Many divers don the mask as they would a firefighter SCBA mask. This is not the best way. Firefighters often pull the straps back over the front of the mask, put their chin in, place the mask on the face, and then bring the
straps back over the head. This is not very efficient for divers for a few reasons. Loosen the straps all the way. Keep the pony regulator mouthpiece in your mouth as it sits in it’s neck strap. Grab the bottom two straps – one in each hand. Pull the straps over your head, pulling the two bottom straps down to your neck. As the mask comes over your face, let the pony mouthpiece drop out of your mouth and set the chin. With one hand hold the face plate of the mask hard against your face to make a seal so you can get air after you clear it. (only need to clear it if you are underwater). Keep the hand there and use the other hand to pull a middle strap back and snug. Switch hands and snug up the other middle strap. Then do the two bottom straps. Save the top strap for last and don’t pull it more than two inches.
Is there a table with the descent rates for different objects (i.e. rifles, pistols, etc.)?…
- What this question is referring to are drop rates of objects. Drop rates are used in conjunction with current and depth to calculate the most likely location a search object will be on the bottom. Use the drop rate and the depth to calculate how long it will take the object to drop. As long as it is in mid-water, the current will affect it. So for examples we have found that on average a human body will drop at about 2 feet per sec on fresh water and 1 to 1 ½ feet per second in salt water. We do not have a table for other items. We suggest that when a call comes in to search for a particular object, find a similar one and do a re-enactment.
How do you decide how wide to make each sweep in arc, dock walk, or other solo-tethered-tender-directed-diver patterns?…
- The following is based on solo-tethered-tender-directed diving. The distance between sweeps depends on the size of the search object, bottom composition and visibility. Let us first look at visibility and bottom composition. Consider a silt bottom lake with ten foot visibility when it is undisturbed. This last word is very important. Few divers have been trained how to cruise a foot off the bottom without kicking up any silt. Therefore, that ten foot visibility can become zero visibility in matter of seconds as an over-weighted diver lands on the bottom. Even if the diver does not move, allows the silt to clear and then lifts off the bottom and cruises without making a mess, there is a chance that the search object has been covered with a fine layer of silt, hiding it from view if it is small enough. Once the diver starts searching by feel, then there goes the visibility. Increased loss of visibility is one of the many reasons why solo-tethered-tender-directed divers are far more effective and safe than putting more than one diver down. So, visibility is based on what the diver is able to see on a return trip sweep. Let us take the optimal situation that the diver has excellent buoyancy control skills with neutral weighting and can make a nice slow descent, stopping a few feet from the bottom. The diver can swim a taut line a few feet off the bottom without stirring any silt. If such is the case then we can say that the diver has ten foot of visibility. The bottom has minimal weeds, rocks, and is relatively flat.
Now we can look at the search object size. If it is an adult body then the sweeps can be ten feet wide. That allows the divers the ability to double check each area between sweeps, which is a good idea because sometimes a 180 degree angle change could make a difference. Take the same scenario but this time make the search object a hand gun. If you can be sure that silt did not cover the gun then a visual search can be done, and the suggestion is halving the sweep width to feet. If we have an average diver that will kick up the bottom then the diver has to tell the diver how much visibility there is. If electronic communication systems are used then the diver simply states it verbally. If not, then when the tender gives the diver a “1” to tell the diver to “stop, face the line, take up line tension,” the diver makes a visibility evaluation. When the tender gives a “3” or “4” to go left or right, the diver moves to the sweep distance that is half the visibility for a body, and a quarter of the visibility for a weapon, and returns the signal. The tender makes a notation of how far the diver moved in and voila, the tender knows how wide the sweep should be.
Other than attention span, is there any reason to limit a zero-visibility search dive to 20-25 min. if conditions are good?…
- Attention span is a key issue when it comes to searching. For those of you not familiar with this concept, we know that for most divers on a zero-visibility dive, after about 15 minutes there is a little voice that says something to the effect of, “why am I here?…, let’s get this over with…” After 20 minutes the little voice has been known to say, “It’s not here, I’m not going to find it here…” Once that happens, no matter how hard you search, your search quality has decreased. Divers need to have constant mind’s eye focus to visualize everything they touch. Most teams have a diver that we call a magnet. This magnet will find whatever you want as long as you put the magnet in the right area. Magnets have nonstop mind’s eye focus with a 100% belief that they will find the search objects. Most of us can keep this going for 20-25 minutes in blackwater. Yes, there are other reasons. How do you feel after doing an effective search dive that lasts 40 minutes? Whipped. Can we put you back in safely and effectively in an hour to do another search? No. If we keep searches to a max of 20-25 minutes then we can put the diver back in, in an hour after hydration, if the diver is warm enough. Therefore if a team has three divers and two tenders (primary, backup, and 905 diver, with a primary and backup tender), they can easily conduct 9 search dives in less than 5 hours – which is one dive short of 30,000 square feet for an adult body in blackwater. Nitrogen absorption is another issue. If the team stays with the 50-60 feet depth and 20-25 minute dive maximums then decompression sickness is not a major concern. If you start allowing 30 minute, 40 minute dives, then dive tables become mandatory, and how many tenders can do dive tables?Air management is another issue. Most divers in no current dives can easily perform a 20-25 minute search dive in 30 or 40 feet of water and come back with more than the 1000 psi minimum to be back on deck with. Add the adrenaline of a real call in a rescue mode and air consumption can easily double. Then that 20-25 minute time is not that short. Or, add a current. A diver who normally breaths 20 psi/min SAC can easily go to 100 psi per minute in 15 feet of water in a 1.5 knot current. A depth air consumption rate of 100 psi /per minute means the diver should only have a 15 minute dive.If you go to 55 feet, then 20-25 minutes may be too long in regards to air since the diver will be breathing almost three times the amount of air as on the surface. Other factors such as exertion and cold can also greatly increase air consumption. Attention span also relates to the primary and backup tenders. Primary tenders have to keep all their visual and mental focus on their divers, and have to make sure the search pattern is accurate. Backup tenders have to have equal vigilance regarding search pattern accuracy, diver breathing rates, and diver search rates, and have to accurately record all this information on the search pattern profile map. In the hot sun, in the cold, even in average weather conditions, how long can tenders maintain safe and effective, continuous vigilance? We have found this to be 20-25 minutes. Then consider that backup and 90% divers are waiting their turn to be the next primary as they sit or float as contingency divers for the primary diver. If the primary diver has a 45 minute dive, then the backup has to wait 47 minutes to dive and the 90% diver has to wait over an hour and a half to dive. If it is too hot or cold, that could mean that one primary diver wipes out two contingency divers. What an unnecessary waste that will also cause frustration and future voluntary dehydration on the part of contingency divers who refuse to wear adult diapers. So yes, attention span and searching quality of the primary diver, attention span and vigilance on the part of tenders, air management, and nitrogen absorption are all important factors that make 20-25 minute max dive times for non-ice conditions. In ice conditions we use 15-20 minute max dive times.
When doing an arc pattern, what is the average goal of how long an arc sweep is? What is the angle of the arc?…
- Usually if you use a ¼ of a circle as your arc then you will have a decent size search area. Sometimes teams listen to a convincing witness and make a very narrow arc. Generally, that’s not a good idea. Don’t short cut. Also, if you make a ¼ of a circle arc pattern (the pie shaped piece of search pattern is a quarter of a pie) then you can easily figure out the length of each diver’s sweep by plugging in the diver’s distance out into the chart we have in our book Public Safety Diving (PennWell Publishing, 340 pages, 2000). Then you can add up each sweep and see if the diver’s search rate was good for the size of the search object. If the rate was too fast then the area may need to be re-searched.
Can a team safely run a dive operation with four people?…
- Our standard requires three divers and two tenders: primary diver, backup diver, 90%-ready diver, primary-tender, backup-tender. Butch came up with the term 90%-ready diver more than 20 years ago, but he did not make it mandatory for our standards until about seven years ago. The reason he made it mandatory was because he observed a few occasions when a backup diver was not able to get to a primary diver in less than two minutes either because the backup diver could not equalize or had an equipment failure. We are constantly working a contingency plan that has an extremely high chance of succeeding. If a call comes in for an officer down in a law enforcement incident, or a firefighter down in a fire issue, is just one backup person sent? Now there is a way of getting around only having 4 people. We did this with the Paratroopers in Alaska who only have 4 person crews. There was a primary tender and diver, and a backup diver and tender. The trick was that the backup tender was fully dressed as a backup diver. Then they were trained extensively until they could do the following: The primary diver called for help and the backup diver was deployed. The backup diver was shut down for a problem. The backup tender was in the water and heading down the primary diver’s tether line in less than 60 seconds. If you can do that consistently, then that is a way of using a four person crew if that is absolutely all that is available. It requires frequent and intense training, and a higher degree of physical fitness on the part of the backup tenders/profilers/90%-ready diver person.
What is the Valsalva Maneuver…
- An understanding of Boyle’s law is primary to understanding the function of a valsalva maneuver. As ambient pressure increases the volume of a gas correspondingly decreases. Imagine an upside down empty bucket with a ten pint volume. Push it under the water with the open side down to 33 feet and the volume of the gas inside the bucket will be 5 pints with the gas having twice the density as it had on the surface. As we descend in the water the gas density in our ear increases with the increasing pressure and the volume of the gas decreases. That is what causes discomfort when we swim to the bottom of a pool or descend in an airplane. In diving the Valsalva maneuver refers to holding the nose and mouth closed and gently blowing against these closed airways. The result is increased pressure that forces air into the eustachian tubes into the middle ear. This is done to equalize pressure in the middle ear when a person descends to a greater ambient pressure such as when diving into a swimming pool or descending form altitude in a car or plane. Gentle is key word because a too forceful valsalva can result in a round window rupture and an oval window break – both of cause serious vertigo and potential damage/infection to the inner ear. Scuba Divers should not perform valsalva maneuvers or other breath-holding equalization methods while ascending because that is a risk to lung barotrauma. A three foot rise with a full lung breath-hold can performate lung tissue. Divers need to hold onto a line or have their eye on their depth gauge when performing these maneuvers in midwater. Keep in mind that every pint of gas is approximately a pound of buoyancy so a 6 pint inhalation to perform a valsalva maneuver is similar to dropping 6 pounds of lead off one’s belt – not a good thing. Gentle maneuvers use less air so there is less of a buoyancy changes. Blackwater divers who cannot read their depth gauges should practice in a pool to make sure they can maintain their position in the water column when performing valsalva maneuvers without a down line. Equalization should be performed about every two feet of descent, especially in the shallow depths up to 15 to 20 feet. A diver can feel pressure when the pressure on the tympanic membrane (ear drum) from the external water exceeds the pressure in the middle ear by as little as 20 mmHg (25 cmH2O). Pain can develop if equalization does not take place from the surface to 6 feet of depth. Equalization should be performed before any discomfort is felt. If the diver does not successfully equalize, and pain is felt, and the diver continues to descend, then a locking effect can take place that can prevent the diver from successfully equalizing. Visualize the volume of gas in the middle ear becoming smaller, with the result being a vacumn created in the middle ear. This vacumn sucks mucus up the eustachian tube into the middle ear, thereby causing a physical obstruction. If the diver continues to descend then edema, hemorrhage, and further mucus blocking can occur in the middle ear to the point of where the tympanic membrane reaches a nonflexible point as it is pulled into the inner ear. This can result in a membrane rupture. This rupture can result in temporary yet severe vertigo and vomiting, which could have serious consequences. Tenders should make sure that divers can equalize prior to dressing. If you cannot equalize on land where there is no increased ambient pressure, how can you equalize underwater? Divers need to remember to perform frequent, gentle equalizations, and to not perform them while ascending. Risk factors for eustachian tube blockage include: improper or infrequent equalizations, congestion from allergies or infections, alcohol consumption, premenstrual mucus buildup, not descending feet first, cigarette smoking, and some mucus producing foods such as dairy products and citrus juice.
What should you do if the water is deeper than 60 feet?…
- The LGS standard for low visibility searches is 50 feet with a possible 10 foot extension for teams trained to the Phase 2 level. If your community has water between 60 and 100 feet and wants your team to be capable of searching at those depths then the community has to come up with the funding for the training and equipment to do such dives. The training is not only for the team but for the local EMS and hospital emergency department so that they can take care of a diver who has experienced a decompression illness injury (DCS, AGE, or other barotraumas). Searches at depths greater than 100 feet require surface supply diving to meet the safety requirements of internationally accepted standards. Depths below 50 feet compound every aspect of the operation such as air consumption, nitrogen absorption, line patterns, search times, and contingency procedures. A small problem at 20 feet can quickly become a large problem at 80 feet.
Could you clarify the NFPA levels of duty? – Awareness, Operations, Technician…
- Awareness training is usually about 4 hours in duration and teaches students how not to do further harm. Anyone who would respond to a specific type of scene should have at minimum awareness level training for that type of incident. Examples included ice, ocean, and moving water. Awareness level personnel can secure the scene by designating hot, warm and cold zones. They can identify hazards, number of victims, begin interviewing witnesses, and can call for appropriate resources to the best of their ability. Operations personnel can perform all duties of the operation that do not involve direct contact with the hazardous atmosphere, which is defines as an atmosphere that does not sustain life. Water fits that definition. Technicians are at the highest level of training because they have direct exposure to the hazardous atmosphere. In surface ice incidents chief tenders, line handlers and other shore personnel would be at the operations level, while the rescuers who go on the ice are at the technician level. In diving incidents tenders are operations and divers are technicians. Ice diving operation tenders are in a gray zone between technicians and operations because in real incidents the ice is unsupportive. A real call means one victim already fell through, so there is a good chance that tenders will fall through and will have to perform their duties form in the water. Such tenders wear the same personal protection equipment as surface ice rescue technicians. Incident command should have at minimum awareness level training, and a technician level advisor should be consulted when making a plan of action.
Are there any major differences in procedures between an urban and a small rural team?…
- There are many factors to consider. Number of available personnel per shift is an example. FDNY Rescue Company dive teams were easily able to meet the minimum 5 personnel necessary to run a dive call, while Game Wardens in Louisiana in rural areas generally only have two officers in an area at a time. Yet, in rescue modes, even urban area Los Angeles Sheriff’s Department marine patrol only have two deputies per boat, which means as per their current standards, one diver is called on to perform a search. Water contamination is another important factor. Often urban areas present with a greater variety of contaminates in greater quantities than rural areas. But this is far from a rule. Very rural farm communities with pig factory farming, for example, can have seriously hazardous water pollution. Budgets are another issue. Most of us think of urban teams as having more teams than small rural teams. Urban departments may have more money, but they also have many more personnel. For a small rural team to make the change from wetsuits to vulcanized EPDM rubber drysuits may cost less than $8,000 for its six divers. For an urban team with 50 divers the switch may be overwhelmingly impossible. The cost of training a team of six divers and ten tenders may not only be affordable, but it could feasibly be for free if the team makes the effort to recruit outsiders to pay for the course. Training an urban team could cost upwards of $100,000 when payroll and overtime costs are put in the hopper. This also means that it may be more difficult to update urban teams to safer standards because changing equipment and procedures in large teams can be significantly more costly and time consuming. Urban teams are more likely to have more calls annually so they gain more on the job training. But keep in mind that if safe procedures and the appropriate equipment are not used then more calls means more risk. Rural teams may have great distances to travel if a small number of personnel are responsible for a large district. Winter storms may pose greater obstructions for rural teams if roads are not plowed as quickly as city streets. This decreases the chances for calls to be in rescue modes. To compound the matter, the time to reach appropriate hospital care may take longer. This is true for victims and for team personnel who become injured.
I’ve been in lakes where the bottom is made up of feet of “pulpy” weed waste matter. Is it recommended to descend into this pulp layer to find solid bottom while searching?…
- That depends on what you are searching for. The average child weighs 4-6 lbs underwater and the average adult weighs 9-18 pounds. If you are looking for an adult, and you as a diver are weighted to be 2 lbs negatively buoyant then lay on top of the weeds, and exhale to see how far you sink in the weeds. Every pint of air is equal to about a pound of buoyancy. A normal tidal exhalation is less than a pint. A full exhalation can be more than six pints. If you exhale six pints for example, then you are 8 pounds negative. A child would not sink as far, an adult may sink further. If you are looking for evidence, use a similar object and perform a re-enactment to see where the search object is most likely to be.
Once you rescue a victim as a public safety diver are you required to start CPR as your tender is pulling you to shore if there has only been a few minutes from arrival on scene to finding the victim?…
- CPR is not known to be effective in the water so that is not something that is done. In the old days, for example in the 1970’s LGS used to train PSD divers to initiate mouth-to-mouth because back then EMS often called a long term drowning victim dead. By initiating rescue breathing, EMS personnel were obligated to continue. What we know now is that such in-water rescue breathing can cause more harm than good. Pocket mask use in the water does not mean the rescuer is protected or that the victim will get sufficient ventilations, and in most hands is not a realistic technique. The one time you get vomit in your mouth while attempting to administer ventilations will make you realize that, in today’s world, that is not a good idea. Since divers should not be more than 125 feet away from their tenders, there is minimal time to get back to shore. Attempts to ventilate a victim during this transport process is very likely to force water into the victims lungs and stomach.