USCGC NORTHWIND and USS BURTON ISLAND 

 (AGB 1). Measurement platforms at the 1.5-, 3.0-, 

 5.0-, 12.0-, and 15.0-mile positions were two LVT- 

 3(C)'s, two LCVP's, and one Greenland Cruiser. 



Current profiles were taken at all stations using 

 the biplane (drag) method of Pritchard and Burt.- 

 Metal biplanes with the following characteristics were 

 used in lieu of weighted wooden drags: 



Aluminum 



Drag material (Alclad 24ST) Iron 



Cross plane dimensions 



(inches) 



Thickness 5/32 1/4 



Width 18 18 



Height 12 12 



Ave. wt. in air (lb) 7.34 30.88 



Ave. wt. in sea 4.86 27.04 

 water (lb) 



Velocity range 0.23 0.53 



(3° to 45° wire to to 



angle, knots) 0.98 2.33 



Wire angles were determined with inclinometers 

 using standard oceanographic observing techniques. 



Surface currents were determined from drifting 

 aluminum biplanes submerged 3 feet beneath the 

 sea surface. To minimize wind effects biplane support 

 floats were constructed to provide only a slight posi- 

 tive buoyancy. Velocity was calculated from the time 

 required for a 200-foot drift of the submerged bi- 

 plane. An initial drift of 50 feet was allowed before 

 commencing measurement to obviate inertial effects. 



Surface currents and velocity profiles from 5 

 to 45 meters were taken at approximately half-hour 

 intervals. Measurements at the 1.5- and 3.0-mile posi- 

 tions were curtailed early, since increasing seas neces- 

 sitated returning to shore the amphibious vehicles 

 located at these positions. 



In addition to surface current observations and 

 velocity profiles using the biplane method, for com- 

 parative data a series of velocity measurements were 

 taken at the 20-mile station using an Ekman current 

 meter. Roll at the 20-mile position probably did not 

 exceed 2 feet in amplitude during the measurement 

 period. However, even this slight roll will give erro- 

 neous direction and velocity with the Ekman current 

 meter and must be kept in mind when interpreting 

 these data. 



Prior to 0800 the LCVP at the 5-mile position 

 dragged anchor badly and, throughout the measure- 

 ment period, the boat was subjected to a very severe 

 cross chop and roll. This effect probably accounts 

 for the low values prior to 0800. These data have, 

 consequently, been omitted in later transport cal- 

 culations. 



DISCUSSION OF DATA 



Complete surface current observations and ve- 

 locity profile data from the seven stations are pre- 

 sented in the Appendix, tables 1 and 2, respectively. 



Average current velocities of 0.3 to 0.5 knot 

 (zero at the two most seaward stations) were re- 

 corded from 0200 to 0500. Velocities increased rap- 

 idly after 0500 at all stations reaching maximum 

 ■average values of 1.7, 1.8, 1.8, 2.0, 1.5, and 1.2 

 knots, respectively, at the 3-to-20 mile positions. 

 The data indicate that an area of maximum velocity 

 gradient probably exists in the 5-to-12 mile sector. 



All currents were predominantly north-setting, 

 except for low velocity values recorded prior to 0500 

 at the 15- and 20-mile stations. The variation in 

 direction was most pronounced at the 15-mile station, 

 particularly in the surface current observations. From 

 0200 to 0600 the water appeared to be moving 

 slowly in a clockwise eddy from south to north. De- 

 crease in velocity with depth determined by sub- 

 merged biplanes and checked at the 20-mile station 

 by an Ekman current meter was slight throughout 

 the observation period. 



Average current velocities were calculated by 

 computing the arithmetic mean for each set of profiles 

 taken at the anchor stations. These values are pre- 

 sented graphically in figure 2. 



Average hourly wind speeds and tidal data, 

 both measured at the Cape Prince of Wales Station, 

 Wales, Alaska, during the current survey period, are 

 shown In figure 3. Comparison of figures 2 and 3 

 suggests a correlation between current speed, tide, 

 and wind. Since current observations did not cover 

 a complete tidal cycle, positive conclusions cannot 

 be drawn. Data from the electrode system (presented 

 later in this report) show a corresponding early 

 morning increase in water transport during flood 

 tide, but show very little decrease in transport from 

 1245 to 1700 (during ebb tide). The tide range off 

 Wales is small, generally of the order of 8 inches. 

 The change from low tide at 0445 to high tide at 

 1245, on 1 August 1954, measured 11.7 inches 



