INSTRUCTIONS FOR THE ICE PATROL. 



Treasury Department, 

 United States Coast Guard, 



Washington, March 3, 1922. 

 To the Commanding Officers of Coast Guard cutters on ice patrol, 1922: 



l.The Modoc and Tampa are designated to carry out the Inter- 

 national Ice Patrol during the season of 1922. Lieut. Commander 

 B. M. Chiswell is assigned to command the patrol. Lieut. Commander 

 W. J. Wheeler will command until first arrival of patrol commander 

 on patrol. Vessels concerned will make the necessary preparations 

 to carry out these orders. 



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

 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 with these fields as they move to 

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

 giving the whereabouts 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. While on this patrol the Modoc and Tampa will base temporarily 

 and obtain fuel and other necessary supplies at Halifax, Nova Scotia. 

 The two vessels wiU make alternate cruises of about 15 days in the ice 

 region, the 15 days to be exclusive of 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 patrol will be relieved by the second vessel, if possible, at 

 which time the first vessel wiU 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 is absolutely necessarj^ to do so. 



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

 daily radiograms. All times in radiograms will be in seventy-fifth 

 meridian time: 



(a) At 6 p. m. (seventy-fifth meridian time) ice information will be 

 sent broadcast for the benefit of vessels, using 600-meter wav^o length. 

 This massage will be sent three times with an interval of two minutes 

 between each. 



