Location

The St. Lawrence Seaway—Iroquois LockThe St. Lawrence Seaway System provides a navigable channel for vessels between Montreal Harbor and the head of the Great Lakes. The E section under the jurisdiction of the Saint Lawrence Seaway Authority of Canada leads from Montreal Harbor (South Shore Canal entrance) to the Cornwall- Massena International Bridge (about 1.5 miles E of Snell Lock). The navigable distance from the entrance of the Seaway to the downstream gate of Snell Lock is 72 miles (83 statute miles).

The continuation of the St. Lawrence Seaway W to the head of the Great Lakes is described in the United States Coast Pilot, Volume 6, published by the National Ocean Service. The St. Lawrence Seaway was opened to commercial traffic on April 25, 1959.

The distances shown on the charts and on the Seaway mileage signs, measured from the origin of Seaway mileage in Montreal Harbor, are in nautical miles.

That part of the Seaway described in this sector is normally open to navigation on April 1 and closes on December 15; however, the actual dates will depend on weather and ice conditions.

Ice.—The Upper St. Lawrence Seaway usually freezes over from shore to shore for varying periods during the late winter months, except in the rapids section. The opening dates of navigation of the various portions of the Seaway system will be published in Notices to Mariners. In order to keep shippers using the Seaway informed of ice conditions which may affect the closing date, bulletins are published periodically during the of November by the St. Lawrence Seaway Management Corporation.

Tides—Currents.—Between Montreal and Lake Ontario the rate of the current varies directly with the width of the river channel. In the canals the rate is generally slight, with the exception of the Canal de Beauharnois, where the rate, although moderate, will vary with the volume of water used at the power dam. In lakes and open reaches, currents vary between 0.25 and 1 knot, and in the narrower sections of the river between 2 and 3.5 knots. The swiftest currents are to be found in the channel between Cornwall Island and the United States shore, where a current of up to 6 knots may be encountered. The currents, in general, set fair with the channel. Depending of the number and position of sluice gates open on the Iroquois Control Dam, the currents in the E approaches to the Iroquois Lock may, under certain conditions, set across the channel.

Depths—Limitations.—In general, the Seaway accommodates vessels up to 225.5m in length and 23.8m in beam. Vessels with an overall length greater than 222.5m must also meet the following requirements:

1. Vessels must have a rounded stem bar.
2. Vessels must be equipped with adequately powered self-tensioning and rendering winches and fairleads at an approved location.
3. Prior review and approval of ship plans will be necessary before actual construction or modifications are undertaken.
4. Adding to the overall length of a vessel will somewhat decrease existing margins with respect to distances to and from ship arresters. Locking of these larger vessels will require special operating procedures. These will increase the lockage time by 2 to 3 minutes.
5. Mariners must comply with special mooring instructions and procedures when proceeding through the locks.

The Seaway entities will allow vessels with an overall length of 225.5m to transit Seaway locks, subject to the above-noted
requirements.

Vessels with masts that extend more than 35.5m above the water level will not be permitted to transit the Seaway. Vessels
in excess of the maximum permissible draft of 7.92m will be delayed and only permitted to transit when the overdraft has been corrected.

The St. Lawrence Seaway—Iroquois LockDeep-draft vessels in transit between Montreal and Lake Superior pass through the following canals: South Shore, Beauharnois Canal, Wiley-Dondero Canal, Welland Ship Canal, and the Sault Ste. Marie Canal. There are 16 locks in the passage, overcoming a total difference in elevation of 177.7m. In the canal sections where it is flanked by two embankments there is a minimum width of 55m between bridge abutments and 68m in canals flanked by two embankments, to 182m in improved channels.

Between Montreal and Lake Ontario all Seaway locks are 233.5m in length and 24.4m in width. There is a minimum depth of 9.1m over the sills. The minimum vertical clearance of Seaway bridges in this section is 36.6m

Order of Transit.—The Montreal Marine Traffic Regulating Center prepares and maintains an order of transit roster for vessels proceeding into the St. Lawrence Seaway. Vessels shall establish their turn by calling "Channel Montreal" on VHF channel 10 when in all respects ready for a transit stating their name, length, present location, and draft forward and aft. The regulating center will notify the ship in sufficient time to make ready to proceed. In order not to miss their turn, vessels are required to maintain a radio guard on the sector frequency they are in, whether berthed or anchored.

Vessels intending to transit the St. Lawrence Seaway without calling at Montreal are examined by Customs and National Health and Welfare officials at the Longue Pointe anchorage. Inspection by officials of the Department of Agriculture will normally take place at the port of destination.

Vessels intending to transit the St. Lawrence Seaway for the first time without calling at Montreal may have their winches, fenders, mooring facilities, and other equipment required by the regulations inspected by Seaway Authority officials while at anchor off Longue Pointe.

Bascule Bridges.—In the Seaway, the upper ends of bascule bridges in the fully opened position encroach to varying degrees over the vessel channels beyond the vertical face of the lock walls. The minimum vertical clearance between the water surface and the under side of these bridges in the opened position is 25m at the face of the lock wall. Masters of vessels with high stern counters, superstructures, and flared bows that can overhang the top of the lock wall when the vessel is not parallel to the wall must exercise extreme care in navigating through these bridge draws.

Pilotage.—Pilotage is compulsory for vessels in transit through the St. Lawrence Seaway from Montreal to Lake Ontario. Upbound and downbound vessels passing through Montreal Harbor normally change pilots at St.-Lambert Lock. Pilots are also changed at Snell Lock. Downbound vessels from Lake Ontario will be boarded by pilots off Alexandria Point.

Regulations.—The "International Regulations for Preventing Collisions at Sea" are modified in waters under Canadian jurisdiction by various special rules. These rules are included in the Canadian "Collision Regulations."

The Seaway Handbook contains the St. Lawrence Seaway Regulations and certain other information relating to the use of the Seaway. A copy of this publication must be carried on every vessel in transit through the Seaway. It may be purchased from the Information Canada book stores.

In the Seaway, specific speed restrictions are in force for all vessels in excess of 12m in overall length. Speed limits are applicable to both normal and HW levels in the St. Lawrence Seaway Regulations. The speed limits given in this sector of Sailing Directions are for normal water levels. Mariners are cautioned that a lower speed limit may be in effect depending upon the existing water level.