on voice radio, and hoist flag “OSCAR” by day, and flash O to ships astern both day and night. The ship is to put the rudder over to avoid striking the person; she also will not try to pick the overboard person up. The last ship in the column will try to pick up the person. The escort forces will also try to pick up the person. PORT EXAMINATION SERVICE In certain circumstances, it may be necessary for national  authorities  to  control  the  entrance  of  ships into certain ports. The signals in figure 7-4 should be displayed  by  signal  stations  or  by  port  examination service vessels. Examination-service vessels will, in addition, fly by day a distinguishing flag (fig. 7-5). COMMUNICATION CONFERENCES LEARNING   OBJECTIVES:   Explain   the, purpose of the convoy communication and Signalman conferences. Uniformity  of  communications  procedures  is  of the  utmost  importance  in  convoy  communications. General communications instructions, radio and radar watches,   electronic   emissions,   communications security  policies,  and  recognition  and  identification are  the  minimum  that  should  be  covered  by  all communications personnel prior to a convoy sailing. CONVOY COMMUNICATION CONFERENCE The  NCSO  will  arrange  a  conference  to  be attended  by  merchant  ship  radio  officers,  naval communication officers, and senior rating. It will normally take place immediately after the convoy conference  and  will  deal  with  convoy  communi- cations in detail. CONVOY SIGNALMAN CONFERENCE This   conference   is   normally   held   after   the communication  conference  for  Signalmen. The   communications   officer   conducting   the conference  will  ensure  that  Signalmen  are  familiar  with visual signaling used in convoys, especially executive method  signaling,  identification  procedures,  and procedures  for  sending  signals. SIGNAL MEANING RED RED RED FIXED—Do not proceed/Port is closed FLASHING—  Emergency.  Do  not proceed/port is closed GREEN Port is open GREEN You  may  proceed GREEN One-way traffic GREEN Port is open GREEN You  may  proceed WHITE Two-way traffic GREEN Port is open WHITE You may only proceed when ordered GREEN to do so Figure 7-4.—Port traffic signals. Figure  7-5—Examination-service  flag. SUMMARY In  this  chapter  you  learned  how  to  communicate  in a convoy using radiotelephone, flashing light and flaghoist. You learned the function of the convoy organization, including that of the OCA, CDSORG, and the NCSORG. You learned about the different convoy formations and how to change guides. You learned about the port examination services and communication conferences. Review this chapter frequently to become familiar with convoy communication. To become even more knowledgable, study ATP 2, volume II. 7-10