THE GEAR 



Figure 4. — Weight (100 lb. =: 45 kg) being swung over- 

 side at end of towing cable. The weight is a cast-iron 

 tapered cylinder TVi inches (19.0 cm) in diameter, 13 

 inches (38 cm) high with its taper beginning about 9 

 inches (22.8 cm) from the bottom. One-inch (2.54 cm) 

 stock is anchored in the casting and an eye, 1-5/8-inch 

 (4.5 cm) I.D., of the same stock is welded to it. After 

 casting, the unit is heavily galvanized. The diameter 

 of the eye is enough to take a strong shackle and a heavy 

 line through it. Note swivel between the shackles which 

 keeps the weight from twisting the wire. Casing, par- 

 tially shown at lower right, is used to store the weight 

 when not in use. Overside platform at left (also see Fig. 

 5 and 12) shows grill floor (description in text). 



Plankton nets. — The quantitative plankton 

 collections of the CalCOFI are made chiefly with 

 nets which retain organisms ^ 500 microns and 

 ^ 333 microns. 



Note: Most CalCOFI plankton tows were made with a 

 1-m silk or nylon net (ca. 0.5-mm. mesh). The directions 

 for the tow indicate possible single or double rig. 





fc- 



J^. 



k. 



Figure 5. — Overside platform ("bucket") described in 

 text, (also see Fig. 4 and 12), used to facilitate handling 

 gear over water and away from side of ship. (The net 

 is the Soutar-Hemingway Animal Trap (SHAT) used 

 for vertical tows; it is not used or described here for 

 standard collections for CalCOFI egg and larva data.) 



