Return Great Lakes & Seaway Shipping
Return to Coast Pilot index (1) Chart Datum, Lake St. Clair.- Depths and verticle clearances are
given in this chapter are referred to Low Water Datum, which for Lake St. Clair is an
elevation of 572.3 feet (174.4 meters) above mean water level at Rimouski, Quebec, on
International Great Lakes Datum 1985.(See Chart Datum, Great Lakes System, indexed as
such, chapter1.)
Dimensions, etc. (2) Length, steamer track, outlet of South Channel of
St. Clair River to Windmill Point Light House; 18.5 miles.
(3) Lenght (right line), on about longitude 82 45'W.; 26 miles.
(4) Breadth (right line), on about latitude 42 25'N.; 24 miles.
(5) Water Surface of the lake (including Detroit River and St. Clair River); 198 Square
miles (U.S.), 292 square miles (Canada).
(6) Entire dranage basin (including Detroit And St. Clair River); 3,05 square miles
(U.S.), 4,370 square miles (Canada).
(7) General Description.-Lake St Clair is an expansive shallow basin,
with low, marshy shores and a flatly sloping bottom. The lake has a greatest natural depth
of 21 feet. St Clair River flows N and enters from the N part of the lake through several
channels of a wide delta area. The outflow of the lake is at the SW end through the
Detroit River. The Chief importance of the lake is the dredged deep-draft channel that
leads across it to connect Detroit River and St. Clair River. No large commercial
facilities or harbors are on the lake.
(8) Fluctuations of water level.-The normal elevation of the lake surface
varies irregularly from year to year. During the course of each year, the surface is
subject to consistent seasonal rise and fall, the lowest stages prevailing during the
winter and the highest during the summer.
(9) In addition to the normal seasonal fluctuations, oscillations of irregular amount and
duration are also produced by storms. Sudden changes in wind or barometric pressure can
cause fluctuations of 1 foot or more that may last several hours. At other times, strong
winds of sustained speed and direction drive forward a greater volume of surface water
than can be carried off by the lower return currents, thus raising the water level on the
lee shore and lowering it on the windward shore. This effect is more pronounced in bays,
where the impelled water is concentrated in a small space by converging shores, especially
if coupled with a gradually sloping inshore bottom which even further reduces the flow of
the lower return currents. This effect is very pronouced in Anchor Bay.
(10) Weather.-Strong winds associated with squall lines or winter storms
occasionally whip across Lake St. Clair causing a danger to shipping. One July, a line of
thunderstorms generated a 61-knot, 1-minute windspeed recorded by a ship traversing the
lake. Peak gusts at Selfridge Air National Guard Base have been clocked in the 60-knot
range in spring and late fall, and in the 40 to 50 knot range at other times during the
navigation season. Winds over the lakes frequently blow out of the S through W, but
numerous local effects come into play on this shallow body of water. At selfridge,
northerlies and northwesterlies are also frequent, particularly during the morning hours,
while southeasterlies are common during spring and summer afternoons.
(11) While haze, and pollution often often drop visibilties below 7 miles, on 9 to 13 days
per month, they seldom fall to less than 0.5 mile. Fog, the principal cause of very poor
visibilities, is most likely in autumn and early spring. Visibilities of less than 0.5
mile occur on about 2 to 3 days per month during these periods.
(12) Ice.-Ice froms early on this body of water, usually starting in the
shallows of Anchor Bay, along the St. Clair shores, and in the E at Mitchell Bay. Because
of prevailing winds and currents, the W side of the lake is the last to become covered and
the first to clear. Navigation is usually extremely limited by early December. The broken
track through the lake closes quickly, but little rafting or ridging occurs. The head of
the Detroit River is relatively ice free for the entire winter, except for minor ice jams.
Heaviest ice cover usually occurs in late February or early March. Thawing is rapid and is
aided by the winds and currents, which move drifting floes to the head of the Detroit
River, where strong river currents move them downstream. The lake is usually open by early
April.
(13) Navigation regulations.-A vessel traffic reporting system and related navigation
regulations have been established for the connecting waters from Lake Erie to Lake Huron.
(See 33 CFR 162.130 through 162.140, chapter 2, for regulations.)
(14) Vessel Traffic Service.-The Canadian Coast Guard operates a Vessel
Traffic Service in Canadian waters from Long Point in Lake Erie through the Detroit and
St. Clair Rivers to De Tour Reef Light in Lake Huron. (See Chapter 3 and the Annual
Edition of Canadian Notices to Mariners for complete information.)
(15) Pilotage.-The waters of St. Clair River are Great Lakes designated
waters; registered vessels of the United States and foreign vessels are required to have
in their service a United States or Canadian registered pilot. Registered pilots for St.
Clair River are supplied by the Lakes Pilots Association. Pilot exchange points are just
below the Ambassador bridge in Detroit River and off Port Huron at the head of the St.
Clair River in about 43 05'30"N.,82 24'42"w. The pilot boat in the Detroit River
, J.W. Westcott II, has a black hull encircled by an orange band and a white cabin with
the words "U.S. Mail" in black letters. Three pilot boats are at Port Huron:
Huron Belle has an international orange hull with an aluminum cabin, and Huron Maid and
Huron Lady each have an international orange hull with a white cabin. (See pilotage,
chapter 3, and 46 CFR 401, chapter 2.)
(16) Charts 14850, 14853, 14851.-The main vessel route across Lake St.
Clair is through the dredged channel that leads from the head of the Detroit River NE for
about 16 miles to St. Clair Cutoff Channel at the mouth of the St. Clair River. The
channel is well marked throughout its length by lights and lighted and unlighted buoys,
and at its lower end by a 227 45' lighted range NE of Peche Island. A
racon is at the front range light. The front range light is protected by riprap and should
not be passsed close aboard, even by vessels of shallow draft. Lake St. Clair
Light (42 27.9'N., 82 45.3'W.) 52 feet above water, is shown from a white square
tower on a cylindrical base on the NW side of the channel at the slight turn near its
midpoint. A radar beacon (Racon) is at the light.
(17) In September-November 1990, the controlling depth was 25 feet (27 feet at midchannel)
in the Lake St. Clair ship channel.
(18 - 51 omitted)
Return Great Lakes & Seaway Shipping
Return to Coast Pilot index