PHOTO : DOM ROBINSON
The MRS can be worn under the hood of water during normal use and in the event of a diver falling unconscious or having a convulsion ... It shall be adjustable or selfadjusting and shall hold the mouthpiece firmly and comfortably in position .”
How to correctly use a mouthpiece retaining strap ( MRS )
To optimise its life preserving potential , an MRS should be positioned and adjusted so the strap is worn over the back of the head such that when in a relaxed state , the DSV / BOV is held comfortably in position . When diving with a hood , one method to avoid mask and MRS strap conflict , is to wear the diving mask strap under the hood and the MRS on top of the hood . Alternatively , if no hood is worn or both straps are preferred to be worn on top of the hood , the MRS strap may be positioned on top of the mask strap , thus readily enabling MRS fitting , adjustment and removal without interfering with the diving mask .
Bailing out when using an MRS
A common misperception concerning MRS use it a belief that it restricts or inhibits access to alternative breathing gas such as ‘ off-board ’ bail out . This is not the case . An appropriately designed MRS enables the DSV / BOV to be pulled down onto the upper chest , enabling it to be replaced with an alternative breathing gas source . Also , now positioned on the upper chest , the DSV / BOV may be easily re-located in the event of going back onto the rebreather . During an emergency open circuit ascent , if back mounted counter lungs are required to be manually vented via the DSV / BOV , for example when in an overhead / restricted space environment , the MRS may be loosened and / or removed from behind the head enabling this to be undertaken .
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