R.R.S. 'DISCOVERY': SCIENTIFIC EQUIPMENT i6i 



two Steel drums, with cast steel ribbed end flanges, and in each of these the barrel 

 is 12 in. and the end flanges 48 in. in diameter. The drum on the port side is izh in. 

 in length, designed to take 1000 fathoms of steel wire rope if in. in circumference. That 

 on the starboard side is 5 ft. in length and carries =;ooo fathoms of tapered wire rope, 

 1 1 to ih in. in circumference. The rope is guided on to the larger drum by a traversing 

 gear driven either mechanically or by hand, and a similar form of hand-operated gear 

 is fitted to the smaller drum. The engine is capable of developing 50 h.p. with a steam 

 pressure of 150 lb., giving a pull of 3! tons on the rope from the top of the coil. The 

 winch, which weighs 9I tons exclusive of wires, was designed to give a speed of haul 

 on the top coil of 100 ft. per minute; the average rate is, however, in excess of this 

 figure and with large plankton nets and dredges a speed of over 200 ft. per minute 

 can be attained when required. As a protection against weather the winch is fitted 

 inside a steel deck house, and warping drums, fitted to each end of the shaft, extend 

 outside the house. 



Though some defects are to be noted the winch on the whole proved very satisfactory, 

 working smoothly and easily under all conditions. 



In order to resist the enormous lateral thrust caused by winding in long lengths of 

 wire rope under high tension, the end flanges of the drums, as noted above, were specially 

 strengthened. The larger drum, however, is built in three pieces, riveted together, and 

 on one occasion after deep-water operations it was found that the inner end flange no 

 longer ran true. Later, in Simon's Town dockyard, the wire was rove off, and it was 

 found that the rivets holding the end flange to the centre barrel had partially sheared. 

 Repairs involved the dismantling of the winch house and occupied a considerable time. 

 Experience indicates that large winch drums should, whenever possible, be cast in one 

 piece. 



Some difiiculty was experienced in fitting the automatic traversing gear to the larger 

 drum owing to the taper of the wire rope. The pitch of the screw on the rod which 

 carries the traveller was made to suit the middle diameter of the wire, but in practice 

 this did not work well. When more than half the wire is outboard the traveller, on 

 hauling, moves too slowly, and the wire takes riding turns. To obviate this a clutch 

 and alternative hand gear was subsequently fitted, but it would probably be better if 

 the screw pitch were adjusted to the maximum diameter of the wire. The rollers of 

 the traveller should be fitted with ball or roller bearings and should be sufficiently 

 staggered to allow free passage to the swivel and shackles which form the connection 

 between the wire and the bridles of the trawl. 



The positions of the Pedestal Fair-leads are shown in Plate IX, and two of them 

 are to be seen in Plate X, fig. 2 : all are securely bolted to tie plates lying below the 

 deck and stand with their centres 19 in. above deck level. In the single fair-leads the 

 height of the revolving part is 9 in. and the minimum diameter 9 in.: in the double 

 fair-lead these measurements are 61 and 12 in. respectively. The revolving parts were 

 in the first place made of cast iron, but in the course of a year, during which compara- 



