case, action can be taken on the part of the 

 submersible operator to assist location. A 

 third function served by surface communica- 

 tion applies to those vehicles {e.g., DS-4000, 

 SP-500, SP-3000) which have no routine 

 means of viewing when surfaced but do have 

 radio antennae with thru-hull penetrations. 

 In this case communications are used to 

 apprise the operator of his situation regard- 

 ing retrieval which is accomplished by the 

 support craft and divers. In the pre-dive 

 stage, radio communications also serve to 

 inform the support craft of the vehicle's 

 readiness to dive. 



A radio signal may also be used as an aid 

 to location of the submersible if its frequency 

 is compatible with existing ship systems, and 

 if the support ship is equipped with a radio 

 direction finder. 



Underwater Telephone: 



As a backup to radios, underwater tele- 

 phones may serve as a means of surface 

 communications. In this mode the tele- 

 phone's transducer obviously must be below 

 the sea surface. Several submersibles have a 

 second telephone transducer mounted on the 

 bottom of the vehicle which serves as an 

 alternate communications system. The ma- 

 jority, however, mount the transducer atop 

 the vehicle for communicating with the sur- 

 face when submerged. On the surface this 

 transducer is out of the water and ineffec- 

 tive. 



Flashing Light: 



To facilitate nighttime location a flashing 

 xenon light is atop many vehicles which can 

 be activated from within the vehicle with the 

 hatch closed. Where such lights are not in- 

 cluded, the operator may have the option, if 

 protection from flooding is afforded, of open- 

 ing the hatch and using a battle lantern or 

 flashlight to serve the same purpose. The 

 submersible's underwater lights may be used 

 as an additional means of location by the 

 support craft, but the fact that the lights are 

 underwater limits their use as long range 

 viewing aids. Coast Guard requirements stip- 

 ulate running lights; these may also serve in 

 emergencies as well as during routine opera- 

 tions. 



Radio Signal: 



Only a few submersibles include a sepa- 

 rate, self-powered, radio emergency beacon. 

 DEEP QUEST is, as far as can be deter- 

 mined, the only submersible fitted with a 

 self-powered omnidirectional emergency bea- 

 con which transmits a 121.5 MHz signal to 

 assist homing in by Coast Guard aircraft. 

 The rest rely on the support ship's radio 

 direction finder to obtain a bearing on the 

 vehicle. 



Distress Rockets and Flares: 



Should surface location not be possible 

 through any of the above means, there are at 

 least seven submersibles which carry dis- 

 tress rockets and flares to assist in visual 

 location. Distress rockets (Fig. 14.11) are em- 

 ployed to signal the general location of the 

 vehicle and the fact that the submersible is 

 in extremis. Flares, smoke pots and dyes 

 serve similar purposes, but also present a 

 signal that may be visually traced to its 

 source. 



For safety reasons there is a reluctance on 

 the part of some vehicle owners to carry 

 pyrotechnic devices within the limited con- 

 fines of a submersible's hull, possibly ac- 

 counting for their absence in the majority of 

 vehicles. 



5I6HM. FLARfS 



i 



Fig, 14 11 Distress rockets (left) and hermitically sealed parachute flares (right) may 

 be fired from the launcher (center) earned aboard DEEPSTAR 2000 



671 



