NEW ScubaPro Galileo HUD and FFM HUD Mounts! hand signals divers use to communicate while underwater, FROM SIMPLE DIVE TO SEARCH AND RESCUE: WHEN PLANS DONT GO ACCORDING TO PLAN, HOW TO BE AN ATTENTION-GETTER: SIGNALING DEVICES FOR DIVERS, How to Plan and Enjoy Your Own Shore Diving Adventures, Keeping It Real: The Scuba Skills Refresher, A Handy Way to Communicate: Using Hand Signals and Accessories to Communicate Underwater. Both should be marked with arrows, but the preferred exit can be marked with two arrows in series. 
[26]:Sec. [15] A standard arrangement with wired diver communications is to have the diver's side normally on, so that the surface team can hear anything from the diver at all times except when the surface is sending a message on a two-wire system. For better visibility, your fin needs to be brightly colored (Photo 6).
One option is to deploy your inflatable surface-signaling buoy, also called a safety sausage (Photo 5). 2022 Undersea Systems International, Inc. Industry Professional Pricing Application, Videographers & Photographers (Film & Television). The throat cut signal: "general danger" or "emergency".
IN THE PREVIOUS ISSUE of Dive Training, we discussed the various hand signals divers use to communicate while underwater. 4 bells Facing shot or tender, go left. These used wires incorporated into the lifeline or air line, and used either headsets worn inside the helmet or speakers mounted inside the helmet. 
The signal to change from general to search signals or vice versa is seven pulls, and the meaning of the signals may vary depending on whether it is given by the diver or the tender. Instead, keep both fins on for your safety. [30][15] The surface caller should also give the diver a chance to temporarily suspend or slow down breathing, or stop using noisy equipment, as breathing noise generated by gas flow through the inlet and bubble noise from the exhaust is often so loud that the message can not be heard over it. One bell is not used as a diving signal as it is difficult to distinguish it from a jerk caused by temporarily snagging the line. Not sure Wireless Underwater Communication are the right choice? [51][52], A scuba diver who deploys a Delayed Surface Marker Buoy (DSMB) at the end of a dive may use a pre-arranged colour code to indicate to the surface support crew if there is a problem for which assistance is required. Rope signals used in the UK[47] and South Africa[30] include the following: Signals are combinations of pulls and bells, A pull is a relatively long steady tension on the line. [18], Surface supplied diving uses the widest range of equipment and methods. By knowing the dive plan and reviewing the surface communication signals, you can enjoy a safer dive and avoid possible miscommunication and frustration. The device is waterproof to 40 metres (130ft), and therefore is suited for recreational scuba diving use, but not technical diving. These date back to the time of the use of standard diving dress. You do not need to attempt to swim to the boat. (or other pre-arranged item). With wireless underwater communications you will have the mobile freedom to swim and explore wherever you want, wireless diver-to-diver, or diver to top-side. The staff at your local dive center can demonstrate the various types of surface signaling accessories now available and can help you equip with the safety accessories that best suit the type of diving youll be doing. [1], Silt, or Silting: Palm and fingers down, thumb rubbed against the tips of the fingers[1], I have a cramp: Repeatedly clenching and unclenching fist, and point at cramped area[1], I am on reserve or I am on bailout gas or I am low on gas: Clenched fist held steady, about level with head or chest, palm side usually forward. [TWO] Photo by Barry and Ruth Guimbellot. [17], More recently, through-water systems have been developed which do not use wires to transmit the signal. Hand signals are useful whenever divers can see each other, and some can also be used in poor visibility if in close proximity, when the recipient can feel the shape of the signaller's hand and thereby identify the signal being given. This is considered important both for managing the diving work, and as a safety measure for monitoring the condition of the diver. Diver telephones were manufactured by Siebe-Gorman, Heinke, Rene Piel, Morse, Eriksson, and Draeger among others. This is especially true if you surface far to the side of or in front of the boat. They were first developed for the U.S. Navy in the late 1960s. [53][54], Other minor emergency signals include the use of mirrors, inflatable signal tubes, floating streamers, compressed air sirens, whistles and other noisemakers to alert the surface support personnel of a problem. For example, when entering the water, the current may be virtually non-existent, only to pick up pace during the dive. [1], Line, Line tangle or Cutting the line: The index finger is crossed with the middle finger to indicate line. [16], Written messages on plastic slates can be used to convey complex messages with a low risk of misunderstanding. [42], There are a few tactile signals in use by penetration divers for controlling a blind passage through an area of extremely low visibility, or where the restrictions do not allow the divers to see each other well enough to use hand signals. [37] Some variations include: How much air do you have left? Although you and your dive group are encouraged to stay close to the boat, divers can inadvertently end up surfacing farther from the boat than expected. The equipment used by divers and the pressurised environment are also hindrances to sound-based communication, and the encumbrance of diving equipment, relatively low light levels, and low visibility of many diving environments also hinders visual communication. Two wire systems use the same wires for surface to diver and diver to surface messages, whereas four wire systems allow the diver's messages and the surface operator's messages to use separate wire pairs, allowing simultaneous speech in both directions. This prevents divers from performing at their full potential. If you surface and need immediate assistance, extend one or both arms straight up and wave back and forth repeatedly in a windshield-wiper motion to attract the attention of the boat crew (Photo 4). [22] Breath-hold divers use a subset of the recreational diving hand signals where applicable, and have some additional hand-signals specific to freediving. There are several systems in use, and it is necessary to have agreement between diver and tender before the dive. [16][8], Divers who are familiar with a sign language such as American sign language and equivalents may find it useful underwater, but there are limitations due to the difficulty of performing some of the gestures intelligibly underwater with gloved hands and often while trying to hold something. As of 2021, hard wired (cable) voice communications are still the primary method, supported in major commercial applications by one-way closed circuit video but line pull signals are also used as an emergency backup, and through-water voice systems may be used as emergency backup for closed diving bells. When the bell is ready to surface and the voice communications are not functioning, the bellman will blow down bell gas four times. There are times when you may be able to see the boat, but the crew is unable to see you.
4.8, Through-water communications systems are more suitable for scuba as the diver is not encumbered by a communications cable, but they can be fitted to surface supplied equipment if desired. [7], I'm out of air: "Cutting" or "chopping" throat with a flat hand. 1 pull To call attention, or have completed the last instruction. [56] In North America a red flag with a white diagonal stripe from the upper left corner to the lower right corner is customarily used. [ONE] Signal Im OK by using one or both arms to form an O above your head. The fin signal is only a viable option when surface conditions are calm. Light signals for a vessel undertaking underwater operations at night. [27], Voice activated means that the unit is intended to transmit when the diver's voice activates the microphone. Five or more pulls Emergency, bring me to the surface! [32], The difference in density of the breathing gas causes a non-linear shift of low-pitch vocal resonance, due to resonance shifts in the vocal cavities, giving a nasal effect, and a linear shift of vocal resonances which is a function of the velocity of sound in the gas, known as the Donald Duck effect. For more information about tips on how to be successful in using underwater communications and to find out what factors can affect wireless underwater communications, visit our Wireless Communications Tips page here.
Bells are always given in pairs, or pairs followed by the remaining odd bell. Single side-band suppressed carrier systems may be used, and a 27kHz frequency with 4.2kHz bandwidth is typical. [7], I'm OK: Forming a large circle with both hands above the head: Used at the surface as the OK hand sign can be difficult to see from a distance. If you have sufficient air in the scuba tank, you can use the second stage to inflate the sausage. ALL RIGHTS RESERVED. [31] The use of breathing gases under pressure or containing helium causes problems in intelligibility of diver speech due to distortion caused by the different speed of sound in the gas and the different density of the gas compared to air at surface pressure. The Rimbach system of touch contact signalling:[43], Also known as rope signals, these are generally used in conditions of low visibility where a diver is connected to another person, either another diver or a line tender on the surface, by a rope, airline hose or diver's umbilical. If there is a problem during the ascent, a long continuous blow-down is the signal to stop. When more than one recipient is possible, the caller will also identify the desired recipient by a call up message, and will also usually identify themselves. Like radio, this is done to ensure that the message has a fair chance of being understood, and the speaker is not interrupted. Simply be patient and stay aware, watching for the approaching boat. 1 pull Calling for attention, are you OK? [11] Later, a speaking tube system, patented by Louis Denayrouze in 1874, was tried; this used a second hose with a diaphragm sealing each end to transmit sound,[12] but it was not very successful. [64], The UDI-28 and UDI-14 wrist mounted decompression computers have a communications feature between wrist units and a surface unit which includes distress signals, a limited set of text messages and a homing signal[65][66][67], Methods used by underwater divers to communicate. [7] These signals are often also used by professional divers to communicate with other divers. [62], A deployable, or delayed surface marker buoy (DSMB) is an inflatable marker which the diver inflates while underwater and sends up at the end of a line to indicate position, and usually either that he or she is ascending, or that there is a problem.
It is always important for you and your buddy to be able to communicate with each other as well as with the divemaster and boat crew. Both the AM and SSB systems require electronic transmitting and receiving equipment worn by the divers, and an immersed transducer connected to the surface unit. When a receiving transducer picks up the signal, the ultrasonic signal is converted to an amplitude modulated electrical signal, amplified and converted to sound by the earphone. An audio signal emitted by a submerged transducer travels through the water to the divers, who can hear the sound directly, without signal receiving equipment. The diver pulls down on the buoy line to make the buoy bob in an equivalent pattern to the rope signal. [23], The presence of divers in the water during a diving operation exposes the divers to risks from passing waterborne traffic, and there are internationally standardised shape, light and flag signals to indicate that the diving support vessel is restricted in its ability to maneuver and that there are divers in the water. Pointing at someone changes the reference of the next signal from "I" to the diver pointed at. [28] These systems are used in case of failure of the wired system, and do not rely on the integrity of the bell umbilical, so will work if the umbilical is severed and the bell lost. [44], The US Navy also has a standard set of line signals. This is normal communications protocol, and encourages clear communication, but does not allow audio monitoring of the diver between communications. For commercial diving applications this is a disadvantage, in that the supervisor cannot monitor the condition of the divers by hearing them breathe. Youll save time trying to navigate issues underwater by eliminating confusing hand signals, writing on slates, and the old fashioned bang on your tank method to grab your buddys attention. These devices are usually mounted on a hose between the first and second stage of the regulator and the BC power connector. Buddy reference. [22], The diver's speech is picked up by the microphone and converted into a high frequency sound signal transmitted to the water by the omnidirectional transducer. These may be moored, as a shotline, and indicate the general area with divers, or tethered to one of the divers by a line, indicating the location of the group to people at the surface. two all-round red lights or two balls in a vertical line to indicate the side on which the obstruction exists; two all-round green lights or two diamonds in a vertical line to indicate the side on which another vessel may pass; when at anchor, the lights or shapes prescribed in this paragraph instead of the lights or shape prescribed in Rule 30. three all-round lights in a vertical line where they can best be seen. Another option for signaling the boat crew is to remove one fin and hold it high above your head. Most signals are acknowledged by returning the same signal, which shows that it was received accurately. Alternative surface "OK" signal. succession of 3 bells I am fouled but can get clear without assistance. Pointed down and rotated means a line tie off. 3 pulls You have come up too far, go back down until we stop you.
Two light flashes at the bell means that the surface is not receiving voice communications from the bell. The traditional method of communication was by line signals, but this has been superseded by voice communication, and line signals are now used in emergencies when voice communications have failed. If you are low on air when surfacing, conserve the remaining air in the scuba tank by using this method of inflation. Communication is most critical in an emergency, where high stress levels make effective communication more difficult, and the circumstances of the emergency may make the communication physically more difficult. The highest and lowest of these lights shall be red and the middle light shall be white; a rigid replica of the International Code flag "A" not less than 1 metre (3.3ft) in height. Measures shall be taken to ensure its all-round visibility. Wireless underwater communications uses water to carry an acoustic signal from one transceiver to another, much like the way dolphins use sonar to communicate -the rest is magic (or, technology). Through-water voice communications do not have the same restriction on diver mobility, which is often the reason for choosing scuba for professional diving, but are more complex, more expensive, and less reliable than the hard-wired systems. Wired systems are more popular as there is a physical connection to the diver for gas supply in any case, and adding a cable does not make the system any different to handle. (often for surface decompression). Royal Navy (RN) signals include short, paired "bells" and longer "pulls". Amplitude modulated (AM) and single sideband (SSB) systems provide two-way communications between divers and between the surface and divers. Effective line signals need a free line without much slack before attempting a line signal, the slack must be taken up, and the line pulled firmly. Now we will cover the equally important signals you need to know when on the surface. Wired communications systems are still more reliable and simpler to maintain than through-water systems, and do not require the diver to carry a power source. [7], Look: Point with two fingers to the eyes. Most signals are acknowledged by returning the same signal, confirming that the signal was received correctly. [48], Cave arrows, Line arrows or Dorff markers (after Lewis Holtzendorff) are plastic arrowhead markers which are hooked onto a cave line by wrapping the line around the arrow through the slots. As opposed to hardwired communications which confines you to the length of a cable, wireless communications provides you the ability to communicate with your buddy, or top side, with ease and freedom to simply dive. Either signal is appropriate. Benoit Rouquayrol Auguste Denayrouze: Part 2", "John Player Cigarette Cards - Communications", "The Anthony and Yvonne Pardoe Collection of Diving Helmets and Equipment", Through-water Diver Communication System Test and Evaluation, "About Ocean Reef GSM G Divers Communication System, Yellow", "How to communicate with your freediving buddy", "International Lights and Shapes RULE 27 Vessels Not Under Command or Restricted in Their Ability to Maneuver", "Through Water Communications Further Explained", "Optimization of an hyperbaric speech transcoder", "Use of American Sign Language for Underwater Communication", "20 Common Hand Signals for Scuba Diving", "New Hand Signal For Divers: The P for Plastic", "Cave Diving: Directional and Non-directional Markers 101", "Awareness: Recipe For Successful Cave Navigation", "Eighth Coast Guard District Special Notice to Mariners", "Ask an Expert: Should Surface Markers Be Mandatory When Diving? [45], Public safety divers and some recreational divers use the following line signals while conducting circular and arc searches underwater.[46]. The balls indicate the obstructed side, diamonds indicate clear side. [13] A small number were made by Siebe-Gorman, but the telephone system was introduced soon after this and since it worked better and was safer, the speaking tube was soon obsolete, and most helmets which had them were returned to the factory and converted. The newer audible devices can be heard for miles on the surface. This can also be used to transmit hand signals to the surface if voice communications fails. [20] They are not yet in general use by recreational divers due to cost and the need for a full-face mask. By using a sausage along with an audible device such as a Dive Alert Plus , your chances of being located quickly are much better. Hand signals are the primary method of underwater communication for recreational scuba divers, and are also in general use by professional divers, usually as a secondary method. 5 bells I have found, started or completed the work. Used alone: Get with your buddy: Fists made with both hands, forefingers extended, and hands placed together with forefingers parallel and in contact. 5 or more pulls Emergency, pull me up immediately! They are used to indicate the direction to the exit, and can be identified by feel. *some of our wireless communication products have voice operated transmission (VOX) option as well as push-to-talk. This method is more efficient if you are close to the boat: if the wind is blowing or the water is choppy, the whistle may be more difficult to hear. Colour is often used, but as there are a limited number of standard colours available, and they are often poorly distinguishable in the dark, modifications to shape may be used which can be recognised by touch. [27], The push-to-talk (PTT) method is the most widely available system for through-water communications, but some equipment allows continuous transmission, or voice activated mode (VOX). Recreational divers do not usually have access to voice communication equipment, and it does not generally work with a standard scuba demand valve mouthpiece, so they use other signals. The parties take turns to speak, use clear, short sentences, and indicate when they have finished, and whether a response is expected. [FOUR] If you are in distress and need immediate assistance, wave one or both hands in the air. [10], The original communication between diver and surface attendant was by pulls on the diver's lifeline. [33], Closed circuit video is often fitted to the helmets of surface supplied commercial divers to provide information to the surface team of the progress of work done by the diver. By the mid-1980s miniaturized electronics made it possible to use single-sideband modulation, which greatly improved intelligibility in good conditions. Open circuit breathing apparatus generally produces considerable exhalation bubble noise. (there could be danger ahead or a boat entering the search area). [7], Descend, or I am going down: A fist is made with one hand, thumb extended downward, and hand is moved downward to emphasize direction of travel. [FIVE] The inflatable safety sausage is considered an important safety accessory that should be worn on every dive. For example: The focused beam of a dive light can be used for basic signalling as well. Size of movement indicates severity of leak. Sometimes there is more than one exit from an intersection. [27], Continuous transmission is a mode where one diver transmits continuously. [49][50], Non-directional and hybrid personal line markers are used to indicate the identity of a diver who has passed along the line and has not yet returned to that point. Two styles of flag are in use. Arm held straight up at the surface, Turn or Terminate the dive. [55], VHF radios and personal emergency locator beacons are available which can transmit a distress signal to nearby vessels and are pressure resistant to recreational diving depths, so they can be carried by a diver and activated at the surface if out of sight of the boat. This type of buoy is usually brightly coloured for visibility, and may be fitted with one of the diving flag signals. They are attached to the line in the same way as cave arrows, and are deployed on the way into the cave, usually at critical points such as forks or jumps, and are used to indicate to other divers that someone is further in along the line. Persistent failure to acknowledge may indicate a serious problem and should be resolved as a matter of urgency.
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