The  single  plate  forming  the  rudder  blade  is  fitted  between,  and
riveted  to,  the  supporting  arms,  besides  engaging  a  groove  cut
down  the  back  of  rudder  stock.  Its  thickness  ranges  from  about
I''  in  small  steamers  to  1 J  inches  in  liners.
Braces  are  formed  at  the  ends  of  supporting  arms  which  are
turned  out  to  take  fitted  pintles.  One  (two  in  large  rudders)  of
these  braces  must  be  shaped  to  act  as  a  stopper  when  the  rud-
der is  put  hard-over.    The  pintles  should  preferably  be  fitted


Fig.  138.
356


The  Naval  Constructor


separately  and  of  the  cone  type  shown  in  the  detail.  It  is  bad
practice  to  forge  pintles  on  the  frame,  as  besides  the  difficulty  of
turning  them  in  a  lathe  they  have  the  disadvantage  of  not  being
readily  renewable.  The  best  manner  of  bushing  the  pintles  is  a
matter  of  opinion,  the  simplest  and  probably  the  one  most  favored
being  to  make  the  bushes  of  hard  steel  with  a  flange  to  take  the
tap  screws  securing  theni  around  the  eye  of  the  braces.  The
weight  of  the  rudder  in  small  vessels  is  taken  on  a  hard  steel  disc
pla^  in  the  heel  step  bearing  with  a  hole  through  Uie  heel  step


BOLTED  COUPUHQ


mVETED  JOJNT


m


z
o

o

bJ


fUVETED  JOINT


Pia.  139.
Fig.  140.
