330 ENGINEERING EVALUATION 



permeated the rubber 0-ring seals and the glass lens. Replacement TV cameras were secured 

 and placed outside the hull, looking through the ports on either side of the lab area. No further 

 problems were experienced. 



The slave unit of the intercom became inoperative during the second week of the operation 

 and was replaced by a master unit wired as a slave. This master unit became inoperative 

 after two days of operation. The cause of the failures was not determined. A second master 

 wired as a slave was installed and operated satisfactorily the remainder of the test. The 

 original slave unit is nothing more than a permanent -magnet speaker and should not be af- 

 fected by pressure. The master unit has a transistorized power supply and amplifier and pro- 

 vides amplification for the slave unit. 



Although the electrowriter performed satisfactorily, some ink splattering occurred when 

 the Command Control Center initiated messages. This condition may have been caused by the 

 high ambient pressure. 



No problems were experienced with the entertainment TV and FM music equipment. 



Data-Recording System — The equipment of the data-recording system performed its in- 

 tended function, with the exception of the humidity sensor in the entry area. The major prob- 

 lem with the system was the necessity of recording the data by hand. As can be seen from 

 examination of Tables Al, A2, and A3, data were recorded irregularly and in some cases not 

 at all. The most complete data were obtained by the first team and is considered to be repre- 

 sentative of the operation. 



Equipment 



Refrigerator- Freezer — The refrigerator was marginal in operation and definitely too 

 small in storage capacity. As can be seen in Tables Al, A2, and A3, the refrigerator was ca- 

 pable of lowering the temperature inside the compartment to the desired level of 42 °F during 

 long periods when the compartment door remained closed. However, it did not maintain this 

 temperature level during periods of frequent opening or normal turnover of stored items. One 

 contributing factor was the upright design, which allowed the cold atmosphere inside to "fall 

 out" each time the compartment door was opened. The circulating fan inside the storage com- 

 partment would aggravate this effect whenever the door was opened during the "on" cycle. The 

 major factors, however, were the high thermal conductivity and specific heat of the atmosphere. 



The freezer was not capable of producing the desired temperature of 5°F. As shown in 

 Table Al, the lowest temperature reached was 16.9° F after three days of continuous undis- 

 turbed operation. On Sept. 2, the freezer thermostat was readjusted to 38° F to provide addi- 

 tional refrigerator volume. Freezer operation was affected by the same factors as the re- 

 frigerator. 



Cooking Equipment — The aquanauts did very little food preparation, since most food was 

 canned or precooked and required only reheating. The cook top and the rotisserie operated 

 satisfactorily. The toaster would not toast bread in the helium atmosphere. 



Water Heater — The water heater performed satisfactorily, failing to meet the demand on 

 only a few occasions. When the hot-water supply was exhausted, recovery was effected within 

 a relatively short time, approximately 20 minutes. 



CONCLUSIONS AND RECOMMEInDATIONS 



Hull 



General — Although the Sealab II was not designed for full surface pressurization for depths 

 greater than 280 ft, it can and should be utilized for deeper runs. With the installation of a 

 suitable automatic or semiautomatic pressure-control system, the Sealab II hull could be uti- 

 lized to the continental- shelf depth of 600 ft or more. 



