pai-acliute drogiie array used by Naval Ocean- 

 ographic Office personnel is sliown in figure 

 M-1. The parachutes usually are surplus mate- 

 rial; and the aluminum TV antenna poles, 

 styrofoam block, radar reflector and light, 

 chains, connectors, cables, and weights all are 

 relatively inexpensive so that the entire array 

 can be considered expendable if it does event- 

 ually sink or become lost. Concrete blocks often 

 are used for weights. 



M-4 Assembling the Parachute Drogue. — 



The components of tlie drogue sliould be as- 

 sembled on deck near the point where the 

 drogue will be put over the side. 



Step 1. Assemble drogue according to dia- 

 gram (fig. M-1). 



Step 2. Examine the parachute for tears and 

 rips; fold the chute into the launching carton 

 (a corrugated cardboard carton approximately 

 12 X 16 X 12 inches) ; separate the chute shrouds 

 and attach the spreader bar. 



Step 3. Allow approximately 5 meters of wire 

 rope between the counterbalance weight and the 

 parachute weight when launching a surface 

 drogue. Lower buoy and counterbalance weight 

 into water first; then, lower boxed parachute 

 and weight into water. When launching drogues 

 for greater depth, launch buoy and weight; pay 

 out enough wire rope to obtain desired depth, 



PARACHUTE 



permitting buoy to drift away from ship; cut 

 wire; attacli it to the parachute and weight, and 

 [Hit them over the side. 



M-5 Tracking the Drogue.— The most im- 

 portant pliase of drogue current measurement 

 operations is tracking tlie drogue. A position 

 should be taken at the time of launching, and at 

 approximately each hour as long as the drogue 

 is afloat. Tlie best positioning technique is to 

 iia\e tlie ship come alongside eacli buoy and take 

 a position ; liowever, an alternative teclmique is 

 to position the ship and take ranges and bear- 

 ings to the buoys. Accurate records of time and 

 position are extremely important. A suggested 

 format for logging parachvite drogue data is 

 given in figure M-2, and drogue plots are shown 

 in figure M-3. 



Often, a marked change in drift or a different 

 attitude of the float indicates that a parachute 

 lias been lost or has either opened or closed. En- 

 ter unusual clianges in drift or attitude of the 

 drogue buoy on the reverse- side of tlie log sheet. 



M-6 Retrieving the Drogue. — Generally no 

 effort is made to retrieve the, entire array. It is 

 usually the practice to come alongside the buoy, 

 to lift it aboard, and to disconnect the shackle 

 connecting the wire rope. This permits wire, 

 chute, and weights to sink. The buoys may break 



DROGUE LOG 



LAUNCH 

 SITE NO. 



s- 



Figure M-2. Suggested format for parachute drogue log. 



M-2 



Change 1—1970 



