ENGINEERING EVALUATION 329 



The helium system performed satisfactorily. Approximately 20 percent of the onboard 

 helium supply was used to replace losses through the sanitary drain discharge and by absorp- 

 tion into the sea water. 



The emergency breathing system was not required. However, during on-bottom test pro- 

 cedures, the pressure reducer did not provide adequate flow for all ten aquanauts simultane- 

 ously unless the pressure was increased above the level compatible with the Calypso breathing 

 apparatus. At the end of the test period, excessive corrosion was observed on all quick- 

 connective fittings installed on the Bibb manifolds. The system could have been used in an 

 emergency, but it was considered to be marginal. 



Gas-Sampling System — The gas-sampling system performed satisfactorily and caused no 

 difficulty. 



Arawak System — Evaluation of the Arawak systems by aquanauts of each team indicated 

 that the type of work to be done determined what breathing system was to be used. Team 1 

 utilized the Arawak system approximately 50 percent of the time. The majority of the work 

 required of the subjects was in the close proximity of Sealab. Minor repairs to the vacuum 

 pump were accomplished by team members. 



Team 2 relied on the Arawak approximately 35 percent of the time. The subjects of this 

 team ventured further away from Sealab. In general, no sorties of over 50 ft were conducted 

 by aquanauts using the Arawak. Most Arawak sorties were local, being used for dumbwaiter 

 transfers and general maintenance work on or in the vicinity of the Sealab. 



Team 3 utilized the Arawak system approximately 30 percent of the time. The majority of 

 work assigned to this team was beyond the 100-ft length of the Arawak's hose. No maintenance 

 was performed by subjects of Team 3. 



The primary problem encountered with the Arawak system inside Sealab was that of noise. 

 The noise produced was that of intake and exhaust of the pumps making communications in the 

 entry area most difficult when the Arawak was in operation. 



Plumbing and Sanitary System — Some minor difficulties were experienced with the sanitary 

 drains. The discharge hoses attached to the drains were lighter in weight than those specified 

 and required weights to hold them down and prevent the loss of atmosphere from the water- 

 closet drain. This overboard discharge was shortened during fitting-out to reduce line restric- 

 tion. This modification raised the hose-connection point abo'-e the entry-trunk water level, 

 but below deck level. Some atmosphere loss was reported through the salt-water supply line 

 for the water closet. Apparently the check valve malfunctioned. The manual pumping effort 

 required for flushing the water closet was reported to be excessive. This effort was apparently 

 greater than that required in Sealab I and was due to the smaller flushing capacity of the Sea- 

 lab II water closet. Also the shower tubs would not drain, since the overboard discharge (star- 

 board side) was trapped by the six-degree port list of Sealab. Drain holes were drilled through 

 the port side of the tubs, allowing the water to drain overboard through the entryway. 



Water-usage rates were determined for the first team as shown in Fig. A2. Overall usage 

 rates could not be determined, since the meters were not read regularly, and a leak which oc- 

 curred in the line from Sealab to the surface vessel on Sept. 24 prevented the use of the final 

 meter readings. 



Communication System — Considerable crosstalk was experienced between circuits in the 

 communication system, even though shielded conductors were used in the communication cable 

 of the umbilical cord. The exact cause of the crosstalk was not ascertained. It was found that 

 the shielding of the conductors in the communication cable had not been carried through the 

 patch panels. This failure may have been the problem. Some crosstalk may have been caused 

 by improper shielding and shield grounding of conductors in the Command Control Center. 



The TV cameras became inoperative when high-pressui e helium apparently leaked into 

 the interior of the cameras and placed the components undt. pressure. Although the camera 

 seals were capable of withstanding pressures much greater than ambient, the helium apparently 



