INSTRUCTIONS FOR THE ICE PATROL. 



Treasury Department, 

 United States Coast Guard, 



Washington, February 9, 1923. 

 To the Commanding Officers of Coast Guard cutters on Ice Patrol, 1923: 



1. The Modoc and the Tampa are designated to carry out the In- 

 ternational Ice Patrol during the season of 1923. The Seneca, is 

 designated as stand-by vessel. The senior line officer present is 

 assigned to command the patrol. The commanding officer of the 

 Tampa will command until the arrival on patrol of a senior com- 

 manding officer. Vessels concerned will make the necessary prep- 

 arations to carr}^ out these orders. 



2. The object of the patrol is to locate the icebergs and ice fields 

 nearest to the trans- Atlantic steamship lanes. It will be the duty 

 of patrol vessels to determine the southerly, easterly, and westerly 

 limits of the ice and to keep in touch wi^h these fields as they move 

 to the southward, in order that radio messages may be sent out daily, 

 giving the Avhereabouts of the ice, particularly the ice that may be 

 in the immediate vicinity of the regular trans-Atlantic steamship 

 lanes. 



3. The patrol will continue until the ice no longer constitutes a 

 danger to navigation in the trans-Atlantic steamship lanes. The ice 

 season is usually three months — April, May, and June. 



4. ^Vhile on this patrol the Modoc and the Tampa will base tem- 

 porarily and obtain fuel and other necessary supplies at Halifax, 

 Nova Scotia. The two vessels will alternate on patrol, making al- 

 ternate cruises of about 15 days in the ice region, the 15 days to be 

 exclusive of the time occupied in going to and from base. The patrol 

 commander will so regulate the movements of the vessels that on 

 the fifteenth day after reaching the ice region the vessel on patro] 

 will be relieved by the second vessel, if possible, at which time the 

 first vessel will proceed to base, replenish her fuel supply, and return 

 in time to relieve the other vessel at the end of the latter's 15-day 

 cruise. It is important that the patrol be continuous, and the vessel 

 on patrol must not leave her station until relieved by the other vessel, 

 unless it should be absolutely necessar}' to do so. 



5. Having located the ice, the patrol vessel will send the following 

 daily radiograms. All times in radiograms will be in 75th meridian 

 time: 



