PRINCIPLES OF NAVAL ENGINEERING 



ROPE DRUM ■^ROPE DRUM BAND BRAKE- 



DOUBLE CLUTCH 



ROPE DRUM _^SPUR GEARS 



L.H WORM DRIVE 



HYDRAULIC MOTOR 



GYPSY HEAD 



AC ELECTRIC 

 MOTOR 



47.145 



Figure 21-9.— Typical electrohydraulic winch. 



For all other positions, the lever must be held 

 in position for the desired speed. 



CAPSTANS 



A capstan is a spool-shaped, vertical re- 

 volving drum used for heaving in on heavy 

 mooring lines. When a capstan is used to haid 

 a load, as in mooring, several turns of mooring 

 line are placed around the capstan head. A 

 manpower strain is then taken on the free end 

 of the line. Maintaining the strain causes the line 

 to bind on the capstan head, which in turn hauls 

 the load. 



A capstan head may be a component part of 

 an anchor windlass. Since the shaft for a capstan 

 head is vertical, a capstan is always free of the 

 fair lead problem which is often present in 

 connection with gypsy heads which are mounted 

 on horizontal shafts. A line leads fair to a 

 capstan from any horizontal direction. Capstans 

 that are not components of anchor windlasses 

 are usually electrically powered. 



ANCHOR WINDLASSES 



A windlass is a piece of deck machinery 

 used primarily for paying out and heaving in 

 an anchor chain. A wildcat (drum) may be 

 mounted vertically or horizontally at the end 

 of the windlass shaft for handling the anchor 

 chain. The wildcat is usually fitted with whelps 

 to engage the anchor chain. On the windlass 

 there may also be a capstan head or warping 

 head (concave drum) for handling lines. A 

 vertical-shaft anchor windlass with capstan 

 head is shown in figure 21-11. 



All anchor windlasses were formerly 

 powered by steam, and some windlasses on 

 auxiliaries still use steam as the source of 

 power. Small combatant ships have electrically 

 powered windlasses; larger combatant ships 

 have vertical -shaft windlasses with electrohy- 

 draulic transmission. Hand-operated windlasses 

 are in use, but they are found only on small 

 ships where the weight of the anchor gear is 

 small enough to be handled in a reasonable 



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