during Cruises V and VI, 1953, under the auspices 

 of the Great Lakes Research Institute, University of 

 Michigan. 



OPERATIONS OF M/V WILLIAMS 



Work in L^ke Superior by the U. S, Lake 

 Survey dates back to 1855, when field parties com- 

 menced the original hydrographic survey of the 

 lake. The first navigation chart of Lake Superior 

 was published in 1858. 



Starting in 1900, hydrographic surveys were 

 performed intermittently as required to keep the 

 charts up to date, to supply detail in the more 

 hazardous places, and to investigate reported dan- 

 gers to navigation. 



In 1929, a survey of the offshore waters of the 

 lake was undertaken with soundings (by line meas- 

 urements) spaced 3 miles apart. This survey dis- 

 covered Superior Shoal which is a shallow area with 

 a least depth of 21 feet located in Canadian waters 

 39 miles south by west from the Slate Islands. When 

 this area was swept for least depth in 1941, four 

 peaks were found in an area of about 2 square miles 

 with 21, 28, 30, and 46 feet of water over them 

 and with relatively deep water between. 



A resurvey of the deep water of the lake was 

 commenced in 1956 with recording echo sounders 

 and Shoran, an electronic system for accurately 

 positioning the surveyship the M/V Williams . The 

 sounding lines were spaced 1-1/2 miles apart and 

 all of the deep waters were sounded west of a line 

 from Passage Island through Manitou Island, to 

 Stannard Rock, to Big Bay Point (fig. 4). 



The following year, the survey was continued 

 in all the deep waters east of the 1956 work area 

 except for a section 30 miles wide adjacent to the 

 south shore from Marquette to Whitefish Point 

 (fig. 4). Because of the limited range of Shoran, 

 the vast expanse of waters in the eastern portion 

 of the lake made its use impracticable. An Elec- 

 tronic Position Indicator system--commonly known 

 as EPI-- which is slightly less accurate but has a 

 much greater range, was loaned to the Lake Survey 



by the U. S. Coast and Geodetic Survey and used to 

 locate the soundings. The sounding lines were again 

 1-1/2 miles apart in most of the area covered. A total 

 of 18,540 lineal miles of sounding and 12. 3 square 

 miles of sweeping on shoal areas were recorded in 

 these 2 years of operation. 



Surface temperature readings have been observed 

 and recorded for many years in conjunction with the 

 sounding operations. The surface temperatures were 

 taken hourly during working hours when the surveyship 

 was under way. In addition, subsurface temperatures, 

 obtained by bathythermograph, were taken in 1956 

 and 1957 by the M/V Williams . The bathythermograph 

 observations were taken at approximately 2-hour inter- 

 vals, sea and weather permitting, while the ship was 

 under way along the designated sounding lines (see 

 figs. 5 and 6 for the distribution of these observations). 

 Air temperatures also were recorded each time the water 

 temperature was measured. 



The bottom was sampled, primarily to determine 

 the character of the bottom for anchoring, each time 

 the ship was anchored. 



Field work still needed to complete the revision 

 of the charts of Lake Superior is as follows: (1) offshore 

 sounding adjacent to the south shore from Marquette 

 to Whitefish Point; (2) inshore sounding, including 

 such sweeping operations as may be required, along 

 selected portions of the American shore of the lake; 

 (3) a complete hydrographic survey of the American 

 waters of Whitefish Bay; (4) survey of an area between 

 Isle Royale and the north-shore mainland. 



The 1956 hydrographic survey of Lake Superior, on 

 which Shoran was used for positioning, was conducted 

 by G. P. Schreiber, Civil Engineer, --assisted by 12 

 others- -under the direction of: Colonel E. J. Gallagher, 

 C. E. , U. S. Army, District Engineer; W. R. Laidly, 

 Chief Technical Assistant; and G. E. Ropes, Chief, 

 Charting and Geodetic Branch. 



In 1957, the EPI-controlled survey in Lake Superior 

 was conducted by F. Wells Robison, Chief, Charting 

 and Geodetic Branch, --assisted by 11 others--under 

 the direction of: Colonel E. J. Gallagher , C. E. , 

 U. S. Army, and Colonel E, H. Lang, C. E. , U. S, Army, 



