UNDERWATER RELEASE BOX 

 (door in closed position) 



Figure 7,~ Underwater release box. (A) Messenger strikes this plate to open door. (B) Shackle bolt (attach- 

 ment to wire cable at this point). (C) Door-release mechanism (see Kemp, Hardy, and MacKintosh, 

 1929, for detail drawing of a similar device). (D) Brass ring fits into this slot when box door is closed. 



(E) Wood block provides base for attaching nylon restraining cord, K, and stop for metal door, G. 



(F) Turnbuckle, for adjusting length of the linkage which holds door, G, in closed position, (G) Metal 

 door constructed of 1/8-inch steel plate. (H) 4-lb. lead plate gives steel door proper balance for quick 

 opening, (I) 3/4-inch marine plywood, (J) Shows approximate spacing of 1/4-inch holes which should be 

 drilled in aU plywood sections of box, (K) Nylon restraining cord Umits door opening to 90 position, 

 (L) Metal hinges welded to steel door, G, and to steel plate on box bonom. (M) Surgical rubber tubing 

 (7/16-inch diameter) when stretched, provides the power to open metal door, G. (N) 5/8-inch marine 

 plywood, (O) Metal supports welded to metal plate provide guides for surgical rubber tubing. (P) Holes 

 in metal plate for bolts which attach plate to box bottom. (Q) 12-lb. lead weight aids in sinking box to 

 bottom. Messenger detail: After the release box has reached the bottom, the messenger (5 lb. in weight) 

 is slipped on the cable through the slot opening. Two threaded bolts are then secured before messenger 

 is released. 



