334 ENGINEERING EVALUATION 



Communication System — Inasmuch as adequate and reliable communications between 

 Sealab occupants and surface-control personnel are of critical importance, the communication 

 system deserves special attention. It is recommended that a complete study be made of the 

 communication problems involved in a Sealab-type operation and that the special equipment 

 required be developed. It is recommended that a helium-speech modifier be developed that 

 would operate as an intercom set. Headphones could also be provided for secure communication. 



The electrowriter should be retained, since it has performed satisfactorily in the past and 

 provides a good communication link. In view of the ink- splattering problem experienced in 

 Sealab II, it is recommended that this problem be investigated and corrected. 



It is recommended that the entertainment TV and FM facilities be retained. It would be 

 desirable to have individual speakers at each berth in the sleeping quarters in place of the one 

 central speaker. 



Data Recording System — It is recommended that in future Sealab operations, required data 

 be recorded remotely on the support vessel or on shore. This provision would ensure more 

 complete data records and would relieve the subjects of the task of recording data or servicing 

 recorders. Remote recording would also permit the use of standard off-the-shelf equipment. 

 A separate cable should be provided in the umbilical cord for data-recording circuits. The 

 following is a recommended list of data that should be recorded for engineering evaluation of 

 the next Sealab operation. 



1. Electrical power (watts) 



2. Voltage 



3. Current 



4. Equipment power consumption 



5. Interior hull temperature 



6. Exterior hull temperature 



7. External water temperature 



8. Interior atmospheric temperature 



9. Interior atmospheric humidity 



10. Equipment operation time 



11. Equipment temperature 



12. Simultaneous audible and unscrambled helium speech 



13. Oxygen makeup 



14. Flow in various air ducts 



15. Water usage 



16. Remote readout of all sensing and control devices 



Equipment 



Refrigerator- Freezer — Refrigerator -freezer facilities must be designed and developed 

 specifically for use in the Sealab environment. Commercially available equipments do not have 

 the required refrigeration capacity, insulation systems, or control systems. Consideration 

 must be given to the fact that the thermal efficiency of ordinary insulations will be reduced by 

 an average factor of four. The atmosphere in Sealab is six times as conductive as air and has 

 a much higher specific heat. The frequency of door openings is considerably greater than in 

 normal use. The storage capacity must be increased by a factor of at least three in order to 

 provide adequate storage. A chest type should be considered as a means of reducing heat 

 losses when the doors are opened, and circulating fans which tend to blow out the cold atmos- 

 phere should be eliminated. 



