Neck Dam System

TM 5-4220-226-14&P 1-12. Neck Clamp - continued. 1-13. Neck Dam System. WARNING Never modify neck dam to accommodate a dry suit. Ballooning may occur putting the diver at risk of injury or death. The hood of the wet/dry suit should never be worn inside the helmet. The neck dam seal, communications, and divers breathing will be adversely affected. a. The slot in the yoke that fits around the diver's neck is smaller than his head. It is improbable that the helmet could be accidentally pulled from the head with the yoke in place. b. The yoke hinges into place around the divers upper neck and the lower part of his head. The lower part of the head cushion (inside the helmet) is pushed in by the yoke, thus section the helmet comfortably onto the diver's head. c. The neck dam is sandwiched between the yoke and the lower part of the head cushion, preventing ballooning or any bellows effect from the breathing cycle. 1-14. Life Support System. The Superlite 17B is designed for use with umbilical supplied air and emergency air supply. Only under very controlled conditions should the helmet be used with a self-contained air supply (SCUBA mode). The flow of the breathing medium (air or mixed gas) is described below. 1-4