314 ¢ U.S. Coast Pilot 6, Chapter 10 26 SEP 2021 85°W 84°W 83°W 82°W ONTARIO 2251 NORTH CHANNEL 46°N D E 14885 T 14882 O U R M S O F M A C K I N A A I T A C P S T R N I A T O S U S L A I N G I S E 14864 L A N Cheboygan D 14881 Rogers City 14869 14865 14880 Alpena L AKE HURON 45°N THUNDER BAY UNITED ST CANADA MICHIGAN A TES Oscoda Au Sable Tawas City 14862 44°N SAGINAW BAY Bay Port Harbor Beach Sebewaing 14867 Bay City Saginaw Port Sanilac 14863 Lexington 14865 43°N Port Huron Sarnia Chart Coverage in Coast Pilot 6—Chapter 10 NOAA’s Online Interactive Chart Catalog has complete chart coverage http://www.charts.noaa.gov/InteractiveCatalog/nrnc.shtml 26 SEP 2021 U.S. Coast Pilot 6, Chapter 10 ¢ 315 Lake Huron (1) Lawrence, Great Lakes, Lake Winnipeg and Eastern Chart Datum, Lake Huron Arctic for complete information.) (2) Depths and vertical clearances under overhead (12) cables and bridges given in this chapter are referred to Fluctuations of water level Low Water Datum, which for Lake Huron is on elevation (13) The normal elevation of the lake surface varies 577.5 feet (176.0 meters) above mean water level at irregularly from year to year. During the course of each Rimouski, QC, on International Great Lakes Datum 1985 year, the surface is subject to a consistent seasonal rise (IGLD 1985). (See Chart Datum, Great Lakes System, and fall, the lowest stages prevailing during the winter indexed as such, chapter 3.) and the highest during the summer. (3) (14) In addition to the normal seasonal fluctuations, Lake Huron Dimensions oscillations of irregular amount and duration are also Description Length/Area produced by storms. Winds and barometric pressure changes that accompany squalls can produce fluctuations De Tour Passage to Fort Gratiot 223 miles (steamer track) that last from a few minutes to a few hours. At other Straits of Mackinac to Fort Gratiot 247 miles times, strong winds of sustained speed and direction can (steamer track) produce fluctuations that last a few hours or a day. These Drummond Island (nearest point to 206 miles winds drive forward a greater volume of surface water entrance of False Detour Channel) to than can be carried off by the lower return currents, thus Blue Point raising the water level on the lee shore and lowering it on Breadth at latitude 44°30'N 96 miles the windward shore. This effect is more pronounced in Maximum recorded depth 750 feet bays and at the extremities of the lake, where the impelled Water surface (including St. Marys 9,100 sq mi (U.S.) water is concentrated in a small space by converging River below Brush Point, North 13,900 sq mi (Canada) Channel and Georgian Bay) shores, especially if coupled with a gradually sloping Drainage basin (including St. Marys 25,300 sq mi (U.S.) inshore bottom that even further reduces the flow of the River below Brush Point, North 49,400 sq mi (Canada) lower return currents. This condition is very pronounced Channel and Georgian Bay) at the mouth of Saginaw River. (15) (4) Weather, Lake Huron General description (16) Gales are most frequent in autumn. By late summer (5) Lake Huron is the second largest of the Great Lakes. there is a noticeable increase, lakewide, in the frequency Three large bays extend from the main body of the lake, of gales, and this increase continues until the end of the Saginaw Bay on the west side and North Channel and navigation season. During November and December, Georgian Bay on the northeast side. The lake receives the gales are blowing 5 to 10 percent of the time, while waters of Lake Michigan through the Straits of Mackinac windspeeds of 28 knots or more may be encountered up to and those of Lake Superior from the St. Marys River. 23 percent of the time. These winds are mainly generated The lake discharges at its south end into St. Clair River by winter storms; their frequency falls dramatically in at Fort Gratiot. The lake is a connecting link in the Great spring. By June and July, gales are expected less than Lakes chain. The depth of water in St. Marys River, St. 1 percent of the time, while winds of 28 knots or more Clair River and Detroit River governs the draft of vessels blow less than 3 percent of the time. However, squall navigating Lake Huron to and from Lakes Superior and lines and thunderstorms can produce violent short- Erie. period winds from spring through fall. For example, the (6) strongest measured wind on Lake Huron’s open waters Vessel Traffic Service occurred in August 1965 and was measured at 95 knots (7) The Canadian Coast Guard operates a Vessel Traffic from west-northwest. Shoreline extremes range from 43 Service in Canadian waters from Long Point in Lake Erie to 53 knots. Directions of these extremes are often out of through the Detroit and St. Clair Rivers to De Tour Reef the southwest, but west, northwest and northeast winds Light in Lake Huron. (See chapter 3 and the Annual have set some of these records. Most of the records were Edition of Radio Aids to Marine Navigation-Atlantic, St. set from late fall through late winter. 316 ¢ U.S. Coast Pilot 6, Chapter 10 26 SEP 2021 (8) Recommended Courses on Lake Huron Downbound/Outbound The Lake Carriers’ Association and the Canadian Shipowners Association have recommended the following courses for downbound/outbound and upbound/inbound traffi c in Lake Erie. 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. Straits of Mackinac to: St. Clair River via Round Island Passage―from a departure position 0.5 (0.4) miles east from the center of the Mackinac Bridge, steer 069° for 5.6 (4.9) miles to the east end of Round Island Passage. Then steer 090° for 9.1 (7.9) miles until Bois Blanc Light bears 180° at 2.3 (2.0) miles. Then steer 105° for 14.2 (12.3) miles to 1.0 (0.9) mile north of Spectacle Reef Light. From this position, steer 121° for 58.7 (51.0) miles until Middle Island Light bears 225° at 15.0 (13.0) miles. Then steer 161° for 105 (91.2) miles until Harbor Beach Light 2 bears 247° at 12.0 (10.4) miles. From this position, steer 179° for 51.6 (44.8) miles to a position 005° at 5.2 (4.5) miles from Lake Huron Cut Lighted Buoys 11 and 12, and then steer 185° for 5.6 (4.9) miles to Lake Huron Cut Lighted Buoys 11 and 12. St. Clair River via Poe Reef Passage―from a departure position 0.5 (0.4) miles east from the center of the Mackinac Bridge, steer 122° for 14.2 (12.3) miles passing to the south of the Cheboygan Traffi c Lighted Bell Buoy. Then steer 108° for 5.5 (4.8) miles until Poe Reef Light bears north at 1.1 (1.0) miles. From this position, steer 077° for 3.2 (2.8) miles until Cordwood Point Lighted Buoy 1 bears 196° at 0.5 (0.4) mile. Then steer 053° for 3.4 (3.0) miles until Poe Reef Light bears 254° at 6.1 (5.3) miles. From this position, steer 115° for 61.0 (53.0) miles until Middle Island Light bears 225° at 15.0 (13.0) miles. Then steer 161° for 105 (91.2) miles until Harbor Beach Light 2 bears 247° at 12.0 (10.4) miles. From this position, steer 179° for 51.6 (44.8) miles to a position 005° at 5.2 (4.5) miles from Lake Huron Cut Lighted Buoys 11 and 12, and then steer 185° for 5.6 (4.9) miles to Lake Huron Cut Lighted Buoys 11 and 12. Alpena or Saginaw via Poe Reef Passage―from a departure position 0.5 (0.4) mile east from the center of the Mackinac Bridge, steer 122° for 14.2 (12.3) miles passing to the south of the Cheboygan Traffi c Lighted Bell Buoy. Then steer 108° for 5.5 (4.8) miles until Poe Reef Light bears north at 1.1 (1.0) miles. From this position, steer 077° for 3.2 (2.8) miles until Cordwood Point Lighted Buoy 1 bears 196° at 0.5 (0.4) mile. Then steer 117° for 45.6 (39.6) miles until Presque Isle Light bears 215° at 2.5 (2.2) miles. Then steer 138° for 23.3 (20.2) miles to 0.6 (0.5) mile east of Nordmeer Wreck Lighted Buoy WR1. —for Alpena, steer 189° for 7.0 (6.1) miles to a position 100° at 1.5 (1.3) miles from Thunder Bay Island Light. Then steer 227° for 5.2 (4.5) miles to Thunder Bay Traffi c Lighted Bell Buoy TB, and then steer 304° for 9.0 (7.8) miles to the Alpena Channel Entrance.