.      Tr/32      300,000X32      ...^|,
^  =  "Di XX8.25'      '^  ^^^^  ^^'-  P^'  '^-  ^°-

Jib.  —  Total  compression  on  jib  -  P  =  80,000  lbs.  -h  3500  lbs.
=  83,600  lbs.  8-inch  extra  strong  pipe,  outside  diameter
D  =  8.625  ins.,  inside  diameter  d  —  7.625  ins.
Modulus  of  elasticity  E  =  25,000,000.
Moment  of  inertia  I  ^  ^{D*  -c^)  =  ^  (8.625*  -  7.625)*  - 106.
Length  Z  =  189  ins.
CoeflScient  of  safety  =  n.
P     1^?I'        _Tr^E'I  _2X  25,000,000  X  106      ^
n'  l^  '    ^  "   P'l^  83,500  X  189»


The  Naval  Constructor


DIAORASf   OF  STRESSES    AITD   BENDINa

MOMxurra  on  anchor  craitb.
Anchor  Crane  Stresses  409


Area  of  section  »  12.7  sq.  ins.
Fibre  stress  =      '        =  6580  lbs.  per  sq.  in.
Tie  RodB.  —  Diameter  =  2}  ins.,  tension  on  one  tie  rod

24,250  ins.
Fibre  stress  =  .  f.^^^^^     =  6830  lbs'


Spreader.  —  Section  at  hub  of  spreader.
Moment  of  inertia  for  axis  a;  —  a::  "  /,  =  2267,

/«       2267

Bending  moment  for  axis  x  —  x\^  507,000  in.-lbs.
Fibre  stress  fx  =     ^In      ^  2010  lbs.  per  sq.  in.
Moment  of  inertia  for  axis  y  —  j/:  »■  /y  =  186,

Z»  ~  1^  -  41  3  V

Bending  moment  for  axis  y  —  y  —  200,000
in.-lbs.
Fibre  stress  /y  =      .  *  ^


u    iJFui


41.3  K tb' ^


Fio.  222


—  4830  lbs.  per  sq.  in.
Area  of  section  ^  49.5  sq.  ins.
Compression,  18,800  lbs.
Fibre  stress  Jc  —     .!.  ,    =  380  lbs.  per  sq.  in.
4y.o

Total  fibre  stress

/x  +/»  +/*  =  2010  H-  4830  H-  380  =  7220  lbs.  per  sq.  in.
Section  18  ins.  from  hub.
