Depth charges, like aircraft torpedoes , have both air and 

 water flights. Several different designs of depth charge were 

 studied chiefly to determine their drag and stability with a 

 view to improving their accuracy and increasing the velocity 

 of their fall in the water,, Similar studies were also made 

 on a group of aircraft bombs. 



Still another development in the field of ordnance was 

 the depth charge Intervalometer „ The use of closely spaced 

 patterns of fast sinking depth charges from surface craft 

 imposes demands on the release gear not likely to be ful- 

 filled by manual operation. As finally developed, the depth 

 charge intervalometer had as its heart a 25-position 6-bank 

 rotary selector switch which connected the electrical firing 

 circuits to the various tracks and projectors at the correct 

 time and in proper sequence. 



Also developed was the Mark 53 bomb rack which made it 

 possible to launch fast sinking depth charges from lighter- 

 than-air craft as well as from surface crafts. 



Lastly 5, there was the antisubmarine scatter bomb. This 

 was a cluster of small shaped-charge projectiles with an 

 appropriate scattering and fuzing mechanism. The weapon 

 could be launched from standard airplane bomb racks, and was 

 designed in such a way that after release the projectiles 

 spread out to form a regular pattern when they struck the 

 water,, They armed in the air after a short delay and fired 

 on impact with a surfaced or submerged submarine. 



Lights and Fla res . 



Float lights and flares were also developed by Division 6 

 and, though not strictly ordnance items, they may be discussed 

 briefly here. 



The Mark V and Mark VI float lights were developed at 

 the New London Laboratory for use by s on cbuoy- equipped air- 

 craft, to replace the Mark IV which had too short a burning 

 time for a blimp, after it had dropped a flare to mark the 

 location of a suspected target „ to circle and return to the 

 target area. The Mark VI was essentially a group of Mark V s s 

 mounted in a single unit and so arranged as to burn In series. 

 Its primary use was tc mark the position of aircraft-launched 

 ERSB's, 



- 103 



