Lake Michigan
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348 ¢ U.S. Coast Pilot 6, Chapter 11 19 SEP 2021 Chart Coverage in Coast Pilot 6—Chapter 11 86°W 84°W NOAA’s Online Interactive Chart Catalog has complete chart coverage http://www.charts.noaa.gov/InteractiveCatalog/nrnc.shtml ONTARIO 86°W MICHIGAN 14902 14908 14911 14915 Gladstone L A K Escanaba E H U R O 14909 N WISCONSIN Y 14881 A B N E 14902 Menominee E R 14912 G 14917 14942 45°N 14910 Sturgeon Bay GRAND TRAVERSE BAY 14918 14913 14919 14907 Green Bay 14903 6 14939 PORTAGE LAKE 1481 N 14938 Manitowoc A Manistee 14922 G Ludington I 14937 Sheboygan H L AKE WINNEBAGO 14922 C I MICHIGAN WHITE LAKE M 14935 Muskegon E 14934 Milwaukee Grand Haven K 14933 43°N 14924 A 14931 L 14932 Racine 14925 Holland 14904 14906 14930 Benton Harbor 14927 St. Josephs Chicago 14928 14929 Calumet Harbor 14926 14905 INDIANA ILLINOIS 19 SEP 2021 U.S. Coast Pilot 6, Chapter 11 ¢ 349 Lake Michigan (1) produced by storms. Winds and barometric pressure Chart Datum, Lake Michigan changes that accompany squalls can produce fluctuations that last from a few minutes to a few hours. At other (2) Depths and vertical clearances under overhead times, strong winds of sustained speed and direction can cables and bridges given in this chapter are referred produce fluctuations that last a few hours or a day. These to Low Water Datum, which for Lake Michigan is an winds drive forward a greater volume of surface water elevation 577.5 feet (176.0 meters) above mean water than can be carried off by the lower return currents, thus level at Rimouski, QC, on International Great Lakes raising the water level on the lee shore and lowering it on Datum 1985 (IGLD 1985). (See Chart Datum, Great the windward shore. This effect is more pronounced in Lakes System, indexed as such, chapter 3.) bays and at the extremities of the lake, where the impelled (3) water is concentrated in a small space by converging shores, especially if coupled with a gradually sloping Lake Michigan Dimensions inshore bottom that even further reduces the flow of the Description Length/Area lower return currents. This condition is very pronounced Chicago to Straits of Mackinac 321 miles at Green Bay Harbor. (steamer track) Length at longitude 87°30'W at the 307 miles (15) south end and longitude 85°45'W at Weather, Lake Michigan the north end (16) Rough water is created when strong winds blow over Breadth at latitude 45°25'N 118 miles a long fetch of water. Northerly winds cause this on the Maximum recorded depth 923 feet south part of the lake and southerly winds have the same Water surface (including Green Bay) 22,300 sq mi effect on the north part of the lake. They raise dangerous Drainage basin (including Green Bay) 67,900 sq mi seas and generate hazardous currents at harbor entrances. Winds with southerly components are prevalent during the entire navigation season. Northerlies are a little less (4) General description frequent but are common particularly in spring. The sea conditions are worst in October and November, when, (5) Lake Michigan is the third largest of the Great Lakes and is the only one entirely within the United lakewide, wave heights of 5 to 10 feet (2 to 3 m) are States. The only natural outlet of the lake is at the north encountered about 35 percent of the time. In October, end through the Straits of Mackinac. At the south end of south through southwest winds are most often responsible, the lake, the Illinois Waterway provides a connection to while by November west through north winds often the Mississippi River and the Gulf of Mexico. The north generate rough seas. Seas of 10 feet (3 m) or more are part of the lake has many islands and is indented by encountered 3 to 5 percent of the time from November several bays; Green Bay and Grand Traverse Bay are the through March. Extreme waves of 20 to 22 feet (6 to 7 m) largest. The shores in the south part of the lake are regular, have been encountered. During the spring, high seas are and it has been necessary to construct artificial harbors. infrequent, but 5- to 10-foot (2 to 3 m) seas develop 15 to The forested shores in the north part of the lake are 30 percent of the time in the south and 20 to 40 percent sparsely populated, while those in the south part are near in the north. Summer seas climb above 10 feet (3 m) less the heart of the great urban industrial area of the U.S. than 1 percent of the time, while those in the 5- to 10-foot Midwest. (2 to 3 m) category drop to less than 20 percent in June and July. By August, the fall buildup begins. (17) Gales are most likely from September through April, (12) particularly in the fall. During this season gales blow 3 to Fluctuations of water level 7 percent of the time; speeds of 28 knots or more occur (13) The normal elevation of the lake surface varies from 12 to 20 percent of the time. Strong winds often irregularly from year to year. During the course of each blow out of the west and northwest, making east shore year, the surface is subject to a consistent seasonal rise harbor entrances dangerous. The strongest measured and fall, the lowest stages prevailing during the winter over-the-lake wind was out of the west-southwest at 58 and the highest during the summer. knots. However, since Green Bay recorded a 70-knot (14) In addition to the normal seasonal fluctuations, southwesterly gust in May 1989, it is not unrealistic to oscillations of irregular amount and duration are also 350 ¢ U.S. Coast Pilot 6, Chapter 11 19 SEP 2021 (6) Recommended Courses on Lake Michigan Southbound/Inbound The Lake Carriers' Association and the Canadian Shipowners Association have recommended the following courses for downbound/outbound and upbound/inbound traffi c in Lake Michigan. These courses are recommended and recognized for the Great Lakes by both Associations, with navigation safety and application of the Collision Regulations always taking priority. While strict observance of these courses is recommended for all Masters, Navigating Offi cers of the Watch, and Pilots for their respective vessels in the interest of navigation safety, these are recommended and voluntary lake courses. They are delineated on general and other charts of the Great Lakes both in paper and electronic formats. The distances given in the text for these courses are given in statute miles with the nautical mile equivalents shown in parentheses. Common Course from Mackinac Bridge to Southern Lake Michigan Ports (via Lansing Shoal) From a departure point under the center span of the Mackinac Bridge, steer 279° for 19.9 (17.3) miles to a point 1.5 (1.3) miles north of White Shoal Light, then steer 277° for 17.8 (15.5) miles until Lansing Shoals Light bears 276° at 3.0 (2.6) miles. From here, steer 267° for 3.0 (2.6) miles to a point 0.5 (0.4) mile south of Lansing Shoals Light, then steer 240° for 30.0 (26.1) miles to 30 Mile Haul at position 45°40.915'N., 086°06.235'W., and then steer a course to desired destination below. Calumet or Indiana Harbors―steer 196° for 208 (180.7) miles to position 42°47.000'N., 087°15.500'W., then steer 188° for 69.5 (60.4) miles to position 41°47.200'N., 087°27.200'W., and then steer 185° for 3.8 (3.3) miles to Calumet Harbor Entrance Channel or continue on to Indiana Harbor. Gary or Bu ngton―steer 196° for 208 (180.7) miles to position 42°47.000'N., 087°15.500'W., then steer 183° for 74.7 (64.9) miles to position 41°42.200'N., 087°20.100'W. From this position, steer 165° for 3.1 (2.7) miles towards Gary or steer 222° for 3.4 (3.0) miles toward Buffi ngton. Burns Harbor―steer 196° for 189 (164.2) miles to position 43°03.000'N., 087°09.300'W., then steer 179° for 94.8 (82.4) miles to a point 2.0 (1.7) miles north of Burns Harbor East Light. Chicago―steer 196° for 208 (180.7) miles to position 42°47.000'N., 087°15.500'W., then steer 192° for 63.4 (55.1) miles to a point 3.0 (2.6) miles east of Chicago Harbor. Milwaukee―steer 206° for 113.7 (98.8) miles to position 44°12.650'N., 087°08.800'W., 18.0 (15.6) miles east of Rawley Point Light, then steer 202° for 88.7 (77.1) miles to a point 2.5 (2.2) miles east of Milwaukee Harbor. Sturgeon Bay―steer 220° for 85.3 (74.1) miles to position 44°45.000'N., 087°15.000'W., 4.0 (3.5) miles southeast of Sturgeon Bay Ship Canal. From Lansing Shoal to Port Inland From a departure point 0.5 (0.4) mile south of Lansing Shoals Light, steer 276° for 15.3 (13.3) miles to a point 1.6 (1.4) miles due east of Seul Choix Point Light, then follow the lighted ranges north to Port Inland. From Port Inland to Southern Lake Michigan From a departure point 1.6 (1.4) miles due east of Seul Choix Point Light, steer 213° for 19.8 (17.2) miles to 30 Mile Haul at position 45°40.915'N., 086°06.235'W., and then steer a course to desired destination listed below using the Common course from Mackinac Bridge to Southern Lake Michigan Ports.