additional personnel will inevitably occur. 

 Since such needs are met from shore-based 

 activities, the support ship must be capable 

 of communicating at least to the source of 

 such support. Quite frequently, it is possible 

 to operate using only the nearest marine 

 operator for such shore communications. The 

 primary difficulty with this arrangement is 

 that one must frequently wait for a period of 

 time to make the call. This makes for diffi- 

 cult schedule keeping if a predesignated time 

 is set for situation reports. On the other 

 hand, as long as this inconvenience is appre- 

 ciated beforehand, the commercial operator 

 serves adequately. 



During a number of open-sea operations 

 with U.S. Naval agencies, a Single Side Band 

 (SSB) radio was installed on the support ship 

 for direct communications with the agency 

 involved. Using this system is more conveni- 

 ent than going through a commercial opera- 

 tor, but the cost can be quite severe, because 

 both the shore and sea components must be 

 furnished and installed. 



The allocation of radio frequencies for use 

 at sea is governed by the Federal Communi- 

 cations Commission for non-government 

 users and the Interdepartment Radio Advi- 

 sory Committee for government users. It is 

 beyond the scope of this discussion to relate 

 the details of obtaining frequencies and the 

 attendant legal considerations, but reference 

 (11) presents a succinct treatise highlighting 

 the pertinent rules and regulations for U.S. 

 users. 



Sub-Surface Communications: 



Communications between the submerged 

 vehicle and its support ship serve a variety 

 of purposes. For the most part, however, the 

 dialogue is concerned with status reports — 

 more simply, to enable the support ship to 

 keep abreast of what's going on in the sub- 

 mersible. In an emergency the purposes and 

 needs are quite different, and the considera- 

 tions involved in selecting a carrier fre- 

 quency and the nature of the device are 

 discussed in Chapter 14. 



Once the vehicle is submerged the fre- 

 quency of conversations with the surface is 

 minimal; purposefully so, because the pilot 

 and observer(s) have enough work to do 

 without distractions from above. For this 

 reason several operators have designed a 

 code whereby all routine (and emergency) 

 traffic is transmitted with minimal dialogue. 

 One such code is presented in Table 10.6 and 

 was used between DS-4000 and its support 

 ship. Such codes also conserve power and, in 

 the event that reception is weak or garbled, 

 can be more easily understood and inter- 

 preted. 



Probably the simplest code used to ask if 

 things are going routinely is to click the 

 transmit button two or three times. Such 

 clicks are quite distinguishable in the vehi- 

 cle, and the operator need merely click back 

 a return OK. 



When a submersible has no independent 

 means of navigation and is required to follow 

 a certain path, frequently it is tracked from 



TABLE 10.6 DS-4000 RADIO/TELEPHONE CODE LIST 



Prefix 



Suffix 



Emergency Signals 



FIRE 



UNCONTROLLED ASCENT 



UNCONTROLLED DESCENT 



HUNG ON OBJECT ON BOTTOM 



MUST EXIT VEHICLE 



CRANE IS INOPERATIVE 



NECESSARY TO DROP FORWARD 



BATTERY 



COLLISION (on surface) 



REOUEST IMMEDIATE PICK-UP 



CALL -MAY DAY 



492 



