b. Copies for via addressees who have yet to endorse the basic letter. (Show these addressees in  a  via  block.  If  two  or  more  via  addressees remain,  renumber  them,  starting  with  a  1  in parentheses  before  the  next  recipient  of  the package.  Don’t  number  a  single  remaining  via addressee.) c. Copy for the originator of the basic letter. (Use  a  copy-to  block.) d.  Copies  for  any  earlier  via  addressees  and any   earlier   copy-to   addressees   only   if   your endorsement  is  significant.  (Add  these  addressees to   your   copy-to   block.)   Routine   endorsements include  “forwarded,”  ‘‘ forwarded for considera- tion, ” and “forwarded recommending approval. ” Significant  endorsements  include  “forwarded recommending   disapproval,”   “readdressed   and forwarded,” and   those   with   substantive comments. e.  Copies  for  any  copy-to  addressees  your command  adds.  (Include  these  in  your  copy-to block.  To  the  right  of  each  of  these  addressees, type  (complete)  to  show  that  your  endorsement includes  the  basic  letter,  enclosures,  and  prior endorsements.) f.  Copy  for  your  file Don’t repeat in your reference and enclosure blocks  any  references  and  enclosures  shown  in  the basic letter or prior endorsements; show only the references and enclosures you add. Assign letters to  all  references  you  add,  even  a  single  one,  by continuing any sequence of letters begun earlier. Likewise,  assign  numbers  to  all  enclosures  you add. Send  any  enclosure  you  add  to  the  action addressee.  Also  send  it  to  the  originator  of  the basic letter if that activity lacks it. The enclosure’s importance will determine whether others should receive it. Omit   enclosures   to   any   addressees   who have  them  already.  Similarly,  omit  enclosures to   any   addressees   when   sending   them   is impractical. SPEEDLETTER Use speedletters for urgent UNCLASSIFIED matters  that  don’t  require  electrical  transmission. The  speedletter  calls  attention  to  the  need  for priority  handling.  Use  it  because  speed  of  delivery is  important,  not  just  because  completion  of  the form  is  easy.  Avoid  issuing  directives  through speedletters. When  speedletters  arrive  from  other  activities, process  them  before  routine  mail.  Similarly, action  officers  are  to  give  them  prompt  atten- tion. Prepare  a  speedletter  on  this  special  form: Naval Speedletter, OPNAV 5216/145 (Fig. 10-8). The  form  has  six  identical  pages  with  carbons between  them.  The  top  three  pages  are  for  out- going   copies;   the   bottom   three   pages   are   for internal use. If  you  need  a  continuation  page,  use plain  paper  and  follow  standard  letter  practice in   setting   margins,   numbering   pages,   and   so on. MEMORANDUM A  memorandum  is  used  to  correspond  in- formally  within  an  activity  or  between  several activities.  Choose  the  format  that  suits  the subject,  occasion,  and  audience.  Your  choices, starting  with  the  most  informal,  are: a. The printed memorandum form (Fig. 10-9) b. The plain-paper memorandum (Fig. 10-10) c.  The  letterhead  memorandum  (Fig.  10-11) d.  The  memorandum-for  (Fig.  10-12) If  the  subject  is  insignificant,  no  file  copy is required. BUSINESS  LETTER Use  the  business  letter  to  correspond  with agencies  or  individuals  outside  the  Department of  the  Navy  who  are  unfamiliar  with  the  standard letter.   It   also   may   be   used   for   official correspondence  between  individuals  within  the Department of the Navy when the occasion calls for  a  personal  approach. Normally,   the   text   should   be   single-space within  paragraphs  (see  Fig.  10-1  3).  Do  not  indent or   number   main   paragraphs.   If   the   letter   is likely to run eight lines or less, you may start the address  more  than  two  lines  below  the  date, use  side  margins  as  wide  as  2  inches,  indent paragraphs,   and   double-space   throughout   the text. Use  Sincerely  for  the  complimentary  close of  a  business  letter.  Start  typing  at  the  center of  the  page  on  the  second  line  below  the text. 10-13