Transcript Full Face Mask and Wireless Communications
Full Face Mask and Wireless Communications
East Carolina University Diving & Water Safety 2002
Overview
This course introduces the diver to the techniques of full face mask scuba and wireless SSB underwater communications. The course covers benefits, limitations, disadvantages, and hazards of: full face masks, and u/w wireless communication. This module includes lecture, confined water practice sessions, open water skills evaluation, and a written exam.
Goals of Training
To provide an overview of full face mask and half mask diving equipment and techniques.
To allow full face mask diving and wireless communication to be experienced in a controlled setting.
To provide an understanding of the advantages and limitations of full face mask diving.
To introduce divers into the correct protocols for underwater speaking and communication.
To introduce divers to emergency procedures specific to full face mask and half mask diving equipment.
Outline of Training
Lecture Communicating and Speaking Underwater Equipment Maintenance Advantages and Limitations Choosing Equipment Emergency Situations Pool work Openwater work
Communicating and Speaking Underwater
Traditional underwater communication involve the use of visual or tactile techniques.
Hand signals, slates, squeezes, pulls, etc.
These techniques are useful but tend to be slow and limited.
Communicating and Speaking Underwater
Under normal scuba conditions, speech is impaired by two factors: The lack of an adequate airspace in front of the mouth.
The scuba mouth piece.
Communicating and Speaking Underwater
Providing an airspace in front of the mouth allows divers to speak and be understood by another diver close by.
Use of underwater SSB (single side band) equipment extends the range of the spoken word underwater.
Communicating and Speaking Underwater
To make yourself understood you must: Speak Slowly Enunciate Properly Speak words individually Time exhalations to minimize bubbles (this may be necessary when listening also.) Do not speak over other divers Do not clutter the airwaves -e.g. singing, swearing, etc.
Equipment
AGA EXO-26 Half Mask SSB 2000 SSB 3000 XT-100 Buddy Phone MKII Buddy Phone 3000-S (surface unit) CDK-4 Surface Kit
AGA
The Divator MK II, commonly referred to as the AGA Mask, manufactured in Sweden by Interspiro Inc.
The AGA differs from other full face masks in that the regulator hose comes into the mask from the left side.
AGA
The Aga has a flat visor, the sides of which are mat finished to avoid optical distortions.
The visor is considered low volume by full face standards, and is designed to minimize positive buoyancy effect. The visor is closer to the wearer's eyes, giving the user an increased angle of vision.
AGA
The masks have holed studs for mounting glasses.
AGA
The mask is designed with an inner mask that fits over the divers mouth and nose. This inner mask has separate inhalation and exhalation channels which minimize the dead air space in the mask and does not allow for the mixing of inhaled and exhaled air.
AGA
The mask uses a demand style 2 nd stage regulator.
It is not a free flow system.
If the mask is sealed properly, it will only supply air when you demand it.
This is true with both the positive pressure and non positive pressure 2 nd stage regulator.
AGA
Air flows from the 1 st stage via the AGA supply hose into the 2 nd stage regulator then up passages into the mask.
AGA
Defogging Feature: During inhalation, air flows from the breathing valve up through the deminster ports and over the inside of the visor to prevent condensation from forming, and on through the non-return valves into the inner mask.
AGA
Equalizing Pressure: The AGA is equipped with an adjustable nose dam to aid in equalizing pressure in the ears and sinuses.
AGA
The nose dam should be adjusted so that the nose can be engaged with a slight upward pressure on the mask.
AGA
Purge Button Placement: The purge button is located on the right side of the mask on the end of the regulator.
AGA
Breathing Resistance: Breathing resistance will increase slightly if the diver is in a face up position. This is less noticeable with the positive pressure version of the AGA.
A poor fitting, non-positive pressure mask, may seep water around the face seal under these conditions.
EXO 26
EXO 26
The EXO-26 full face mask is designed and manufactured by Diving Systems International of Santa Barbara, CA. It differs from the AGA by having a ridged exoskeleton and it does not have an inner mask.
EXO 26
The volume of air held in the mask, while it is on the divers face, is higher than the AGA.
EXO 26
Scuba Style Ear Equalizing: A large nose pocket in the mask allows divers to equalize ear pressure by pinching the nose.
EXO 26
Regulator Adjustment Knob: The EXO-26 is not a positive pressure breathing mask. However, the regulator can be adjusted by the diver during use to reduce breathing resistance. Adjustment can be made to the point of the regulator free flowing.
EXO 26
Automatic Defogging: As the diver inhales, the incoming air goes up through the inlet tube and down across the lens, defogging and flushing the mask with each breath.
EXO 26
Earphone Pockets: The mask seal of the EXO 26 is equipped with pockets which house the earphone portion of the underwater communication equipment.
EXO 26
Purge Button Placement: The purge button is located on the center line of the mask over the divers’ mouth.
EXO 26
Regulator Adjustment: The adjustment knob should be set for easy breathing on the surface. Once under water, the adjustment may be changed to compensate for work rate or other factors.
EXO 26
Breathing Resistance: Breathing resistance will increase in a face up position. If the adjustment knob is too tight and the mask is poorly fit, it is possible for water to leak past the face seal. Usually at the temple area. Backing out the adjustment knob will lesson resistance and prevent leaking. In the face down position, the opposite reaction will occur and the adjustment knob should be turned in to stop any excess regulator flow.
EXO 26
To clear water from the mask, use the purge button. An EXO-26 completely filled with water, should take no more than 3 seconds to totally purge.
Donning & Removing Masks
Place the mask on the face with the chin in the chin cup.
Donning & Removing Masks
Always pull down the head harness (spider) as far as possible at the back of your head
Donning & Removing Masks
Tighten the bottom straps of the spider first, but not all the way.
Donning & Removing Masks
Next tighten the temple straps. Alternate between the temple and bottom straps until the face is positioned properly and snugly into the mask.
The top center strap can is used to give support to the mask while on the surface.
Donning & Removing Masks
To remove the mask, grasp the bottom of the mask on each side where the buckles attach. Grasp the buckle tabs with the thumbs and pull the tabs forward. This will release the lower legs of the spider and allow the bottom portion of the mask to be pulled away from the face as if the mask were hinged to the forehead.
Half-Mask
Half-Mask
The Half Mask is designed to provide an air space over the divers mouth for verbal communication under water. The divers wear their personal mask. The version in our inventory is the HM-2 Mouth Mask produced by OTS.
Half-Mask
The Half Mask is designed to be worn with the Buddy Phone on the right side of the divers head. This puts the mask in the proper position, chin cup down.
Half-Mask
The proper position of the Half Mask on the divers’ face puts the diver’s chin in the chin cup. The upper lip of the mask seals over the upper lip of the diver.
Half-Mask
OTS suggests the Half Mask be donned before the face mask is put in place. The disadvantage to this approach is the scuba mask will be dislodged in an out of air situation.
Half-Mask
We prefer the Half Mask to be put in place over the divers mouth after the diver has donned the scuba mask. This allows the Half Mask to be pulled down around the divers’ neck without dislodging the scuba mask.
Half-Mask
The head strap should be arranged so that it forms a halo around the crown of the divers head.
It is important to tighten the Half Mask straps only enough to provide an adequate seal. Over tightening may cause discomfort and leakage.
Half-Mask
The Half Mask feels less stable on the face than full face masks or normal scuba regulators. Due to the placement of the second stage, it is much easier to bump the regulator and pull the Half Mask down on the divers chin. This usually does not adversely affect the breath-ability of the system, but it does take some getting use to.
Half-Mask
The Half Masks in our inventory have been modified slightly from the standard OTS model. We have placed a fastex buckle on the left side of the head strap. This allows the diver to remove the Half Mask from around the neck without removing the scuba mask.
This is useful in small boat operations where the diver needs to give up the scuba unit before getting back on the boat.
Half-Mask
Purge Button Placement: The purge button is located on the center line of the mask over, or slightly below, the divers’ chin.
Half-Mask
Breathing Resistance: Because of the placement of the scuba second stage, the breathing resistance will increase considerably if the diver is in a face up position. A poor fitting mask may seep water around the face seal under these conditions.
Mask Care & Maintenance
The face masks and breathing valves should be rinsed inside and out with clean fresh water after use.
Special care should be taken with the communication equipment during rinsing!
As with any SCUBA regulator, the purge button should not be pressed during rinsing, if the air is off.
Mask Care & Maintenance
After rinsing the masks, air dry or blow dry using compressed air. Note: Some of the masks trap water after rinsing. Care should be taken to eliminate this excess water by shaking and/or carefully manipulating the mask skirt as needed.
Mask Care & Maintenance
The masks should be stored in a cool, dry place, out of direct sun light.
The lever on a positive pressure Aga should be in the open or “out” position for storage. This relieves tension on the springs inside the regulator.
Communication Equipment
Communication Equipment
There is a variety of underwater communication equipment available on the market.
The equipment in the ECU inventory is manufactured by Ocean Technology Systems (OTS)
SSB 2000
The SSB 2000 may be used with our Positive AGA, or EXO-26 full face masks.
SSB 2000
The unit may also be used as a surface unit when coupled with a CDK-4 Surface Accessory Kit.
The Range of the unit is 200 to 1000 meters.
It is rated for a maximum depth of 400 fsw.
SSB 2000
The housing is constructed of high impact polycarbonate plastic which will not corrode when scratched.
The housing is divided into two major parts, the upper electronics section and the lower battery section. An O-ring between both sections maintains the housings watertight integrity.
SSB 2000
Each unit uses 8 AA Alkaline batteries. This = Approximately 12 hours of battery life (Assuming 10% transmission cycle).
The unit has a red LED to indicate low battery and that the unit has power.
SSB 2000
To test the unit for power, wet the index and middle fingers on one hand and touch the two outside screw heads holding the belt clip to the housing. If the unit has power, the LED will glow. When the diver enters the water, the water completes the power circuit, activating the unit.
SSB 2000
The SSB 2000 has both a Squelch and VOX adjustments located inside the housing.
SSB 2000
The Squelch control allows the background noise heard by the diver to be limited. Limiting background noise (maximum squelch) will reduce the units range. Minimal squelch (clockwise adjustment) will increase unit range, but increase background noise.
SSB 2000
The VOX control (Voice Operated Transmitter) allows the sensitivity of the microphone to be adjusted. Improper adjustment of the VOX control can result in false transmission due to ambient noise. Fully turning the VOX control counterclockwise turns the VOX OFF.
SSB 2000
The unit has a Push-To-Talk Switch (PTT) in addition to VOX.
SSB 2000
The unit has a removable Transducer. The transducer provides the antenna for the transceiver.
SSB 3000
The SSB 3000 may be used with our positive pressure AGA.
The units are designed as diver units only. They may not be used as a surface unit.
SSB 3000
The SSB 3000 has a push-to-talk button located on the top of the unit.
It has an earphone and microphone connector hard wired into the unit.
The transducer is not removable.
SSB 3000
When coupled with the SSB 3000, there is only one connector in the system. This is a two pin connector that attaches to the microphone in the mask.
SSB 3000
The only adjustment available on the SSB 3000 is a squelch adjustment. The recommended squelch setting for the SSB 3000 is a mid-range setting. If the squelch setting is rotated to the maximum counterclockwise position, unit range will be approximately 10 feet (This is not recommended for most applications).
Buddy Phone
XT-100 MKII
Buddy Phone
XT-100: Is designed for use with the HM-2 Half Mask. The half mask units use a potted microphone that can be flooded without fear of damaging the microphone.
Buddy Phone
MKII: Is coupled with an AGA full face mask.
The MKII incorporates a replaceable microphone, a HOT MIC. The HOT MIC has excellent sound quality, but is less tolerant to flooding. The mic uses a hydrophobic membrane that prevents water from entering the microphone to a depth of approximately three (3) feet. Experience has shown that HOT MIC operation is greatly enhanced by keeping the microphone as DRY AS POSSIBLE.
Buddy Phone
Both types of Buddy Phone units in our inventory use one 9 volt Alkaline battery.
Due to the height of the battery, only Duracell or Kodak batteries should be used.
Rayovac or Energizer batteries are too tall and will cause the battery compartment to flood.
Buddy Phone
There is no low battery indicator. When the receiver audio becomes distorted, change the battery. The plug to the battery compartment is O-ring sealed. It is extremely important that the battery cover is thoroughly dry before opening the battery compartment. Water entering the housing can corrode the battery contact springs resulting in system failure.
Buddy Phone
To change the battery: Use as dime or similar coin to pry the battery plug until the latch releases on one side.
Grasp the battery plug and remove it from the main housing.
Inspect the O-ring and the O-ring surface on the housing and verify that there is no dirt or debris.
Buddy Phone
To change the battery: Install a fresh 9 volt battery making sure that the polarity is correct. (Observe the label in the battery compartment.) Ensure that the battery plug O-ring is clean and lightly lubricated with silicone grease.
Re-install the battery plug by inserting it into the battery compartment until both catches engage.
Buddy Phone
The units activate when submerged. Water activated contacts (the two screws on the front of the housing) serve as the sensor electrodes. When the diver enters the water, a small electric current flows between these contacts.
Buddy Phone
The Buddy Phone can transmit approximately 3 meters in air.
This allows the divers to conduct an “Air Test” prior to starting a dive by moistening their fingers and making contact with the sensor electrodes.
Once activated, the unit will remain active for approximately 1 minute.
While the units are activated, press the push-to-talk switch and speak while your buddy listens. Reverse the process. (All units being tested must be ON).
Buddy Phone
The range of the units is 50 to 500 meters depending on sea conditions and noise level.
The maximum operating depth of the Buddy Phone is 130 feet.
SSB 3000S – Top Side Unit
SSB 3000S – Top Side Unit
The unit consists of: an ABS cabinet with lid, electronics, transducer with 55 foot transducer cable, and an AC adapter for recharging the maintenance-free battery.
SSB 3000S – Controls & Functions
SSB 3000S – Transducer & Cable
The surface comm. unit is equipped with a transducer and 55’ of cable.
This transducer must be in the water and out of “object shadow” to permit the best transmission/receiving.
SSB 3000S – Transducer & Cable
The transducer must be kept free of grease and debris. Clean periodically with rubbing alcohol.
DO NOT AFFIX WEIGHT DIRECTLY TO THE TRANSDUCER CABLE!
If it becomes necessary to weight the transducer, to keep it down in heavy current, weight a separate line and secure the transducer to the weighted line.
CDK-4 Surface Comm. Kit
The CDK-4 Surface Accessory Kit converts a SSB 2000 to a lightweight surface unit. This kit consists of a head set with boom microphone and a 55 foot transducer cable.
CDK-4 Surface Comm. Kit
To convert the SSB 2000 to a surface unit: Attach the pin connector for the head set to the earphone/microphone interconnect, Remove the transducer from the housing by turning the large gripper ring clockwise and attach the transducer to the female pin connector of the 55’ transducer cable.
Attach the male pin connector of the transducer cable to the housing at the large gripper ring by turning the gripper ring counterclockwise.
When the transducer cable is connected, the power circuit is completed and the unites LED will glow.
Advantages and Disadvantages
Advantage Full Face Masks offer greater protection than regular SCUBA, when diving in cold and/or contaminated waters.
Disadvantage Full Face Masks & Half Masks are not “standard SCUBA”, this requires additional training for divers to become proficient (task & equipment loading; gear rigging; emergency procedures).
Advantages and Disadvantages
Advantage Full Face Masks & Half Masks allow for verbal communication.
Disadvantage Full Face Masks & Half Masks, because they are not standard SCUBA, may require some divers to unlearn some skills and/or procedures (i.e. out of air situations).
Advantages and Disadvantages
Advantage When used properly, Full Face Masks & Half Masks equipped with communication equipment drastically improves the efficiency and safety of a dive site.
Disadvantage Some Full Face Masks are less abuse friendly than standard SCUBA. This is a function of the communication equipment.
Advantages and Disadvantages
Advantage Underwater communication equipment is an outstanding teaching tool.
Underwater communication equipment permits buddy communication without lessening diver efficiency.
Disadvantage Underwater communication equipment may not be 100% effective under certain conditions.
The use of underwater communication equipment can cause a relaxation in buddy contact.
Advantages and Disadvantages
Advantage Underwater communication equipment promotes diver confidence in poor visibility and other stressful diving conditions by providing the diver a link to their dive buddy and to the surface.
Disadvantage Using this type of equipment requires more logistics than standard SCUBA (i.e. batteries, disinfecting solutions, etc.).
Choosing Equipment For Use
Is non-standard scuba the right choice? This is a question you should ask prior to the start of diving operations. Many diving operations could benefit from using full face or half masks with communication equipment. This is not to say that this equipment is the only choice.
Choosing Equipment For Use
When making these decisions you must consider: The specific diving environment The tasks to be performed The training of the persons involved Expense, logistics and gear availability Fitting masks Gear rigging Hoses and adapters Batteries Wire ties, etc.
Safety considerations
Emergency Situations
The approach in handling out of air and other emergencies is somewhat determined by the equipment configuration being used. The self-rescue options available when employing a redundant air source will not be discussed here.
Emergency Situations
Mask Flooding and Free Flow Out Of Air – Surface Out Of Air – Bottom Second Stage Loss Second Stage Failure Loss Of Communication
Mask Flooding and Free Flow
While not technically emergency situations, a flooding mask or a free flow can be irritating and could escalate into a serious problem under the right circumstances. Both of these problems are usually due to improper mask fit and the position of the divers face (face up, face down, etc.), though damage to the mask is also a possibility.
Mask Flooding and Free Flow
Under most circumstances, all that is necessary to correct these problems is to reposition the mask for a better fit.
Press the purge button to clear a flooded full face mask.
In some instances it may become necessary to give up the mask and switch to another air source. If this happens the options are the same as those for a second stage failure.
Out Of Air - Surface
It should be remembered that once the mask is put in place, you are breathing down your air supply.
If your air supply is depleted at the surface, the mask must be removed before you can breath.
Depending on the surface conditions, making it to the surface with the minimum air limit may not be sufficient.
Out Of Air - Surface
Standard snorkels are of very limited use to a diver equipped with a full-face mask requiring a long surface swim.
Snorkels are available for some full-face masks, but they are not designed for use in a normal, face down, snorkeling position.
They are designed to let the diver breath at the surface without depleting the air in the tank. Standard snorkels are very useful to a diver equipped with a half mask requiring a long surface swim.
Out Of Air - Bottom
When using a full-face mask or half mask configured with standard scuba (BC, gauges, first stage, primary, and octopus), the diver acting as the donor in an out of air situation does not give up the primary regulator.
Because of this, in line/BC integrated octopus devices such as the Scuba Pro Air II or Sherwood Shadow should not be used as the octopus regulator.
A standard scuba second stage with a slightly longer hose is the equipment of choice in this situation.
Out Of Air - Bottom
Depending on the diving environment / situation, divers may want to have a standard scuba mask available as a backup during the dive.
NOTE: While this seems logical in theory, this option should be seriously considered and trained for prior to putting into practice. Each additional piece of equipment adds to the task loading of the diver. Caution should be taken to avoid overloading.
Out Of Air - Bottom
Standard out of air signals are employed in out of air situations involving full-face masks or half masks. These signals should be practiced and reviewed prior to the dive.
Out Of Air - Bottom
An ESA is an option when using a full face mask or half mask.
As with standard scuba, ALL EQUIPMENT SHOULD REMAIN IN PLACE DURING THE ESA.
NOTE: Making it to the surface in a Full face mask or half mask does not end the out of air situation. The mask must be removed before you can breath.
Second Stage Loss
When using a half mask, it is possible for the standard scuba second stage to become dislodged from the mask. If this happens you will notice the mask filling with water and the second stage will not be there when you reach for the purge.
Second Stage Loss
In this situation you have several options: Recover the second stage and replace it in the mask, clear the mask, and terminate the dive.
Remove the mask, switch to your octopus (or the dislodged first stage/less mouth piece) and terminate the dive.
Ask to air share with your dive buddy, remove the mask breath on your buddy’s octopus and terminate the dive.
Perform an ESA.
Perform a positive buoyant ascent. This should always be your last option!
Second Stage Failure
Second stage failure is very rare, but it is a possibility. Options for dealing with this situation are: Remove the mask, switch to your octopus and terminate the dive.
Ask to air share with your dive buddy, remove the mask breath on your buddy’s octopus and terminate the dive.
Perform an ESA.
Perform a positive buoyant ascent. This should always be your last option!
Loss Of Communication
Loss of communication is not necessarily an emergency situation. It can be the result of several factors including, but not limited to: Having the communication signal blocked or distorted by an object or sea conditions.
Insufficient battery.
A bad microphone.
An improperly placed or dislodged ear phone.
Being talked over by a stronger signal.
Unable to hear due to ambient noise.
Loss Of Communication
To deal with these problems: Move out of the shadow of the object blocking the signal, or have the surface transducer lowered deeper in the water column.
Surface and change the batteries.
Surface and change the microphone, or swap out to a different mask.
Monitor the placement of ear/bone phones and adjust as needed.
Loss Of Communication
To deal with these problems: Practice proper transmission protocols. Pay attention to what is being said by others and relay messages as needed.
Have a backup signal to allow for the shutoff of noisy equipment being operated underwater, move away from the noise source until communication is restored, opt for another communication method (i.e. line pulls, hard wire communication equipment).