to the right of the right column. Internal lanes take a number composed of the adjacent column numbers less the prefix 0. The left lane is numbered 01, and the right lane takes the number of the right less the prefix 0 but with the suffix 0 added. COLUMN CALL SIGNS The column number is to be used as the collective call sign for ships in that column, preceded by the word column. Example: Column zero four LIGHT REPEATING SHIPS If the convoy is large, special light repeating ships may be designated to relay flashing-light messages from the commodore. GUIDES OF A CONVOY One ship in the formation will be designated as the convoy guide. The duty of the guide is to maintain accurately the course and speed ordered. If the ships are in a single column, the leading ship will be the guide. If, for any reason, the leading ship falls out of line, the ship next astern of it becomes the guide of the column. If the convoy consists of two or more columns, one of the column guides also must act as convoy guide. The convoy guide must maintain the course and speed ordered, and guides of columns must keep their correct station on the convoy guide. Ships in each column are to keep station on the guide of their respective column. Should the guide be disabled and become incapable of acting as guide, the leading ship of the next column to starboard is immediately to become convoy guide without further orders. If there is no column to starboard, the leading ship of the next column to port is to become the guide. If the convoy is in any formation other than columns in line ahead, a new guide will be detailed by signal. A ship becoming guide will immediately hoist her largest merchant ensign at the masthead. If the commodore has detailed some other ship to act as convoy guide and later wishes to make a further change, he/she will make a signal indicating which ship is to become convoy guide. When this signal is executed, the ship that has been acting as guide will haul down her merchant ensign and cease to act as guide. At the same time, the new guide is to hoist her largest merchant ensign and become the guide. If the new guide is the commodore's flagship, execution of the signal will indicate that the commodore has reassumed the guide. The convoy guide and column guides remain the same if the convoy alters course by any of the following methods: 1. By all ships turning simultaneously less than 90° to starboard or port 2. By wheeling (altering course in succession) 3. By column leaders turning simultaneously, the remainder in succession CHANGES OF THE GUIDE To assist station-keeping in a convoy formed in columns, the convoy guide is to change automatically when all ships turn simultaneously through 90° or more. If the convoy alters course, with all ships turning simultaneously exactly 90° to starboard or port, forming line abreast, the port or starboard wing ship respectively of the new leading line abreast automatically becomes the convoy guide and without further orders hoists its largest merchant ensign. The previous guides of columns, however, do not change but become guides in the line abreast. In figure 7-2, if ships turn together 90° to starboard, number 61 automatically becomes convoy guide. Numbers 11, 21, 31, 41, 51, and 61 remains guide of the respective lines abreast. If the convoy alters course, with all ships turning more than 90°, the ship now leading the column originally led by the convoy guide automatically becomes the convoy guide. The ships now leading the columns become the new guides of their respective columns. Thus, in figure 7-2, if the ships turn together more than 90°, number 44 automatically becomes the convoy guide, and numbers 14, 24, 34, 44, 54 and 64 become the new guide of their columns. When a convoy is in a formation other than columns in line ahead, it may be desirable for the convoy commodore to designate certain ships as group guides. Such ships are to take charge of their groups in cases of emergency and, if necessary, act on their own initiative. 7-6