LARGE PLANKTON NETS iig 



in lo min., the net, hauled at 40 m. per min., travelUng 400 m. in the same time. 

 Thus, if closing be desired on 2000 m. of wire, the messenger must be released at the 

 surface when the recording dial reads 2400 m. Corresponding dial readings can be 

 calculated for any length of wire and for any warp or messenger speed. 



The moment of closing, even in deep water, can generally be detected on deck either 

 by feeling the wire or by watching the drum of the winch which revolves for about a 

 second at high speed as the net, falling back, momentarily ceases to fish. When it has 

 been ascertained that the net is throttled, the open-meshed forward section only con- 

 tinuing to fish, the hauling rate may safely be increased to between 45 and 50 m. per 

 min. It should not however be more. 



When bringing the net on board the release gear, hauled slowly up to the rail, is 

 stopped just outside the fair-lead, and when the warp has been raised as before, the 

 large mechanism is hoisted on board with the winch. The warp, slacked back into the 

 fair-lead, is now hove up until the eye of the hauling rope (Fig. 3, /?), with which all large 

 net rings are provided, can be cast adrift outboard, passed through the fair-lead, and 

 hooked on to a light purchase on deck. With the help of the purchase the heavy frame 

 is lifted out of the water and hauled close up to the rail when the large tackle can 

 be hooked on and the frame hoisted to the derrick head. It is now a simple matter 

 to get the net on board. While the frame is being hauled and hoisted the throttling 

 wire must be brought in simultaneously, hand over hand, otherwise it will slack off 

 and allow the catch in the fore section of the net to drop back and mingle with that 

 in the bucket behind. For easier handling the wire is provided at its forward end with 

 a "tail" of 1 1 in. manilla. 



Throughout the entire operation, while shooting, paying out and hauling, the ship 

 from start to finish is kept dead before the wind. It is impossible in practice to work 

 for long on any other course, for at the low forward speeds employed when hauling all 

 steerage way is lost, and the ship, virtually anchored by the stern, is inclined all the time 

 to come stern on to the wind. When operating long wires under very high tension such 

 a turning movement is apt to have serious consequences, for the warp, leading across 

 the stern, is liable to score deeply into the fair-lead cheeks, and even although the cheeks 

 are recessed, may in a very short time cut its way through and jam on the axle of the 

 horizontal roller. 



