Figure 12. — Cable clamp attaching plankton net lead line to towing cable. Clamp is tightened (and loosened) 

 with a steel rod (suspended in bucket) inserted into bolt eye. Insert: cable clamp, opened, showing grooves to 

 accommodate cable. (See Table 1 for source of supply). Note swivel between the two shackles (see legend for 

 Fig. 6). Small line hanging below man's right hand is the safety line to be hooked to the towing cable above the 

 clamp. Line with hook hanging at side of bucket is used to retain the towing cable, after the weight is lowered, 

 if the ship has a slight way-on so that clamp and inclinometer can be attached. 



b. The net (s) is allowed to stream out (Fig. 

 14) before lowering, and when it is ob- 

 vious that it is not tangled, the wire is 

 payed out at 50 m/min until the desired 

 depth is reached. 



c. At the desired depth, the watch is 

 stopped, sinking time is recorded (item 

 8) , and watch zeroed and restarted im- 

 mediately. 



Note: Since the net is "fishing" on the way 

 down, sinking time is as important as that of 

 retrieval. 



Recording the time is simplified if "Time Net 

 Enters Water" is recorded to the nearest 5 min. 

 (This is the item near 20 — or 20' — Routine or 

 Other, depending on tow — see later) . This time 

 is also recorded at item 6. 



d. When the watch is restarted the net(s) 

 is left at the desired depth for 30 sec 

 (hypothesized that a "falling" net(s) 

 will straighten out at depth in the 30-sec 

 interval). 



e. At the end of 30 sec the watch is not 

 stopped, the angle is recorded for that 

 depth, and retrieval is begun at the rate 

 of 10 m per 30 sec. The angle is recorded 

 at every 10 m in items 20-22 (Routine) 

 or 20'-22' (Other). 



Note: Ship speed, during sinking, times at 

 depth, and during retrieval, is maintained to 

 keep the wire angle at 45°. In dead calm, it 

 may be necessary to run the ship in circles to 

 maintain the wire angle. 



14 



