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- Description:
- One blueprint drawing entitled "U. S. Lake Survey, Detail of Intermediate Sweep Float." The drawing shows the design of a float (buoy) that was used as part of a sweep for obtaining water depth information. The sweep consisted of a line of 15 floats with flags, spaced at 100-foot intervals, that supported an underwater wire at a set depth. The line of buoys would then be dragged across an area of water by launches at each end of the buoy line. If the wire encountered any submerged obstructions, it would cause one or more float (buoy) flags to tip and thereby give an approximate location of an obstruction that could be investigated further. Such obstructions could then be plotted on the navigational charts that were produced by the Lake Survey Office. The plan is dated January, 1915.
- Date Issued:
- 1915-01-01T00:00:00Z
- Data Provider:
- Detroit Historical Society
- Collection:
- Maritime
- Description:
- One drawing entitled "Survey of Northern and Northwestern Lakes, Design of Intersection Protractor." Notes beneath the title indicate that the protractor was "Made under the direction of Major W. L. Fisk, Corps of Engineers, U.S.A., and E. E. Haskell, Prin. Asst. Engineer, by Murray Blanchard, Junior Engineer." The plan is drawn in black ink on linen and is dated April, 1904. The drawing was prepared at full scale and shows plan, profile, and cross-section views for the design of a protractor which was used for drawing lake survey charts. Additional notes at the bottom of the title block give the following specifications: "Make bar of steel, graduated arcs of German silver, and other parts of brass. Protractor arms to be nickel plated. Graduate protractors to 1/2 degree and verniers to 1 minute."
- Date Issued:
- 1904-01-01T00:00:00Z
- Data Provider:
- Detroit Historical Society
- Collection:
- Maritime
- Description:
- One drawing entitled "Survey of Northern and Northwestern Lakes, Design of Intersection Protractor." Notes beneath the title indicate that the protractor was "Made under the direction of Major W. L. Fisk, Corps of Engineers, U.S.A., and E. E. Haskell, Prin. Asst. Engineer, by Murray Blanchard, Junior Engineer." The plan is drawn in red and black ink on linen and is dated April, 1904. The drawing was prepared at full scale and shows plan, profile, and cross-section views for the design of a protractor which was used for drawing lake survey charts. Additional notes at the bottom of the title block give the following specifications: "Make bar of steel, graduated arcs of German silver, and other parts of brass. Protractor arms are nickel plated. Graduate protractors to 1/2 degree and verniers to 1 minute."
- Date Issued:
- 1904-01-01T00:00:00Z
- Data Provider:
- Detroit Historical Society
- Collection:
- Maritime
- Description:
- One drawing entitled "Survey of N. and N.W. Lakes" and "Standards of Length." Notes in the upper left corner show "Lt. Col. G. J. Lydecker, Corps of Engineers, U.S.A., in charge" and that the drawing (Plate I) was "To accompany report of Asst. Eng. E. E. Haskell." The plan is drawn in black ink on linen and is dated July 1, 1898. The drawing shows plan, elevation, and cross-section views of an apparatus that was used to compare measuring instruments against a standard 8 meter bar. The name, "A. Mangelsdorf," is shown in the lower right corner of the sheet.
- Date Issued:
- 1898-01-01T00:00:00Z
- Data Provider:
- Detroit Historical Society
- Collection:
- Maritime
