cury vapor lamps was the relatively long 

 warmup time required to obtain peak output. 

 With tungsten lamps warmup time is about 

 0.5 second; with mercury vapor the time 

 could be as long as 13 minutes in cold water. 

 The report concluded with a preliminary de- 

 sign for lights and ballast units which, in 

 Waltz's opinion, would correct the deficien- 



cies as he saw them. It should be noted that 

 this study was performed in 1970. By now it 

 is safe to assume that several lighting prob- 

 lems are either solved or much reduced, con- 

 sidering the greater experience accumulated 

 and advances in technology over this 5-year 

 period. Figure 10.6 shows a variety of under- 

 water lights for use on submersibles. 



Fig 10,6 Various underwater lights on submersibles: a. Birns & Sawyer, b. Hydro 

 Products, c EG&G International, and d Ikelites pressure compensated by air. 



478 



