U.3.S.  TUCICSR, 
10  August  1918. 
From:  Commanding  Officer. 
To:  Forae  Commander,  U.S.  Baval  Forces  in  Franc®. 
Subject:  Action  with  enemy  submarine, 
knclosure:  Sketch  of  action. 
1.  On  August  9,  1918  at  2:20  p.ra.  (OMT),  in  Latitude 
46®-02’  8.,  Longitude  17°-68f  ». ,  sighted  the  periscope  and  con¬ 
ning  tower  of  a  submarine  bread  on  the  port  bow,  distant  about 
800  yards.  (At  this  time  the  ’’TUCKX^  was  at  the  head  of  a  column 
of  ten  destroyers, (U.f.  .  C0H1J12B  senior  ship),  steaming  south  (  true), 
•peed  twelve  knots,  distance  between  ships  about  three  miles).  The 
submarine  submerged  immediately,  but  not  before  It  was  observed  that 
she  was  heading  about  180°  (true).  .Vent  full  speed  and  headed  for 
a  point  about  200  yards  ahead  of  point  of  submergence,  bent  full 
right  rudder  just  before  reaching  this  point  and  then  let  go  one 
depth  charge,  followed  in  15  seconds  by  the  "I"  gun,  and  then  at 
from  18  to  25  second  intervals  until  number  14,  with  single  charges. 
2.  At  point  14  put  rudder  amidships  until  passing  point  1, 
when  went  south  intending  to  circle  to  the  eastward.  Had  just 
given  left  rudder  at  point  ”B"  when  bow  of  submarine  broached 
abaft  starboard  beam,  heading  in  a  westerly  direction.  Continued 
with  right  rudder,  opened  fire,  and  headed  to  intercept  submarine. 
At  point  ”C”  bow  disappeared,  submarine  apparently  stopping.  Ceased 
firing  and  headed  for  this  place,  hero  the  heavy  oily  wake  ended. 
In  passing  over  this  spot,  the  dim  outline  of  a  long,  large  object 
was  seen,  both  from  forecastle  and  aft,  at  a  distance  of  about  20 
feet  from  the  port  side,  about  £0  feet  below  the  surface,  ano,  making 
an  angle  of  about  30°  with  the  surface.  When  directly  over  this 
object  let  go  numbers  15  and  16  oioargea,  at  about  a  E  second  interval, 
(One  of  these  was  set  at  150  feet  and  the  other  at  100  feet). 
S.  From  point  16,  circled  to  left,  and  returned  to  oil  patch, 
drooping  last  charge  as  shown  at  Lo.  #17*  After  thi  ,  continued 
olrcll'ig  in  vicinity  for  about  one  and  on©  half  hours,  but  saw  no 
further  signs  of  submarine. 
4.  when  submarine  broached,  the  bow  was  just  barely  breaking 
the  surface.  There  was  a  great  disturbance  of  water  throughout  her 
run  near  the  surface  (several  hundre  yards)  and  she  was  api.  are  nay 
eoin«?  at  full  speed  in  an  endeavor  to  come  to  the  but  ace.  *hero 
wac  I  heavy  oily  wafc#  !•«  toxin*  this  run  of  a  few  ^dr®f  jardf* 
and  later,  where  this  wake  ended,  there  was  a  heavy  oi*  patch.  (It 
is  believed  that  the  "FAB KUO”  wae  icon  to  drop  several  depth 
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