The U. S. Fish and Wildlife Service 

 Exploratory Vessel John N. Cobb is described 

 by Powell and Peterson (1957). 



Navigational equipment of the four 

 charter vessels included the following: 

 loran, radio direction finder, fathometer, 

 radio telephone, automatic pilot, and radar 

 (except for the MA Celtic ). 



Each charter vessel had a complement 

 of seven men: a master, four crewman, an 

 oceanographer from the University of Wash- 

 ington, and a Fish and Wildlife Service 

 biologist . 



Figure 2 shows the charter vessel M/V 

 Mitkof , which is similar in appearance to 

 the other schooners described above. 



GILL NET CONSTRUCTION 



The standard gill net set consisted of 

 18 shackles (fig. 3). Each shackle of net 

 was approximately 50 fathoms in length (300 

 feet) and 20 feet deep. Four mesh sizes 

 were used in each set including 6 shackles 

 of 5 1/4 inch, 6 shackles of 4 1/2 inch, 

 3 shackles of 3 1/4 inch, and 3 shackles of 

 2 1/2 inch stretched measure. Gill nets 

 were of nylon constructed in the manner 

 described by Powell and Peterson (1957) 

 with the exception that "Spongex" floats 

 were used in place of cedar in nets con- 

 structed for the 1956 season. Two to six 

 fabricated seine floats (18" diameter) were 

 placed along the string to supplement the 

 wood and "Spongex" floats. 



The 18 shackles were generally arranged 

 in the following order: 5 1/4 inch, 4 1/2 

 inch, 3 1/4 inch, 5 1/4 inch, 4 1/2 inch, 

 juid 2 1/2 inch; the same sequence repeated 

 three times for a total length of approxi- 

 mately 1.05 statute miles. 



A 1/2- inch nylon drift cable was 

 attached along the corkline at every 10 feet 

 on the "shock" net and on the first six 

 shackles to help reduce the strain on the 

 corkline. This cable was attached to 200 

 fathoms of 3/4- inch nylon line, which in 

 turn was secured to the bow of the vessel by 

 a heavy sisail rope which served as a mooring 

 line. The sisal rope and nylon drift line 

 were submerged, acting as a spring line to 

 take up the surge of the vessel. 



The Tordenskjold used a 40-foot trian- 

 gular section of 4-inch cotton trawl net 

 attached at the head of the first shackle 

 to take up the shock of wave action on the 

 gill nets while the Mitkof , Paragon and 

 Celtic used a 180-foot "shark" net for this 

 purpose. Two flagpoles with lights were 

 placed near each end of the string to mark 

 the position of the net during hours of 

 dctrkness. Figure 3 shows a typical gill 

 net set. 



OPERATIONS 



Setting 



The gill nets were set from the stern 

 while the vessel traveled downwind at a 

 speed of about 4 knots. As the last shackle 



4 SHACKLES OMITTED 



- 250 FATHOUS 



Figure 3. — Typical station set. 



