While residents living along the Upper St. Lawrence River between Montreal and Lake Ontario have organized protests over elevated water levels in the river, the inland shipping industry has advised of their crucial need for high water levels to move fully laden bulk carrier ships downstream to Montreal and the Lower St. Lawrence River.
The St. Lawrence River is a vital transportation corridor that moves bulk freight such as agricultural products, mined ores and iron pellets at much lower transportation cost per weight unit than either railway or road transport. There are seven navigation locks between Lake Ontario and Montreal that allow authorities to regulate water levels. At this time of the year, the movement of bulk freight is urgent and elevated water levels allow ships to be more heavily laden without the keels striking the river floor. Low water levels require that ships sail partly laden, in turn requiring additional ship sailings.
While the elevated water levels enhance the viability of inland waterway ship transport, residents who live along the river have protested against high water levels that result in even small waves crossing on to their waterfront property. Some residents blame bow waves from passing ships for having eroded significant proportions of their waterfront property. With a warming climate expected to enhance northern summer farming across much of Western Canada, ships that sail through the St. Lawrence Seaway will carry some of that addition agricultural production in the weeks prior to Christmas.
Ships sail at peak feasibility when sailing fully laden and to do so along an inland waterway requires maximum allowable water depth. Such sailing along the St. Lawrence Seaway has elicited protests from residents whose homes are built along the river and whose shorelines have been eroded by ship bow waves. When ships sail partly laden operate at reduced viability and requiring additional voyages to move the same volume or tonnage of cargo. Precedents exist in maritime transportation whereby shallower draft ships carry massive volume and/or massive tonnage and could do so along the St. Lawrence Seaway.
Implementing such precedent along the Seaway would take several years, provided that political support to such an end materialized. If the ship transport industry and St. Lawrence Seaway were willing to undertake experiments in raising vessel productivity, a possible mutually acceptable solution may evolve whereby the ship industry feasibly moves massive tonnage while residents along the river get to enjoy the benefits of reduced water depth. The experiments could begin in a hydraulics laboratory and involve the combination of water pumps at navigation locks, coupled vessels, bow wave deflectors and ship wake deflectors.
The precedent of the coupled ship is proven in both ocean coastal sailing involving initiatives by Crowley Marine and also on the Great Lakes involving tug barges that actually sail across Lake Superior. Converting a ship to a barge involves increasing its payload by removing fuel tanks and engine, then modifying the stern area with a U-shaped indentation to allow a large tug to couple to the stern to provide propulsion and navigation. Wave conditions are sufficiently calm along the waterway going upstream from Sept Iles, Quebec to Lake Ontario to allow for operation of coupled vessel assemblies.
Few a few days during the months of November and early December, the weather phenomena known as the “November Witch” occurs on the Great Lakes, with winds creating ocean height waves. Severe wave heights sometimes occur in eastern Lake Ontario when shallow draft vessels built to maximum 50-feet beam can divert via the Murray Canal. Extended length coupled ships would need to sail on re-adjusted schedules to avoid the occasional severe wave heights that occur on eastern Lake Ontario. Quite often, the projected weather reports are sufficiently accurate to alert sever wind conditions that would cause the severe waves.
Transit Navigation Locks
During the experimental phase involve Seaway-max size of barges, there would be need to decouple the 2-unit assembly to transit navigation locks. While a Seaway-max ship might need 15,000 horsepower to sail at 10 knots, it would briefly need only 120 horsepower to sail at two knots to exit from the navigation lock. During upstream sailing with the upstream navigation doors open, water pumped into the lock between the locked downstream doors and vessel stern would produce a water-current that would help to float the barge out of the lock, making it available for the tug to transit upstream.
During downstream sailing with downstream doors open, flowing water from upstream into the space between the vessel stern and locked upstream doors would produce a water-current that would help push the barge from the lock. Crew would activate a short-term onboard propulsion system to move the vessel from the lock, to await the arrival of the tug. When sailing beyond the locks, a barge of 720 feet and a tug of over 300 feet length would cover about 1,000 feet and push the identical bow wave and produce the same wake as shorter vessels.
Extreme Length Vessel
Researchers at University of Michigan examined a concept two-unit coupled ship that involved a “tug-ship” pushing and navigating a barge built to 50 percent greater length and sailing on relatively calm water. For Seaway operation, the “tug-ship” would be built to 480 feet in length and carry the combination of engine, fuel and some payload, with the barge carrying mainly payload with short-term propulsion capability to exit from navigation locks. There may be scope to build a single test unit of such a configuration from older ships, to sail along the Seaway at shallower draft than present vessels.
If the inland waterway ship transport industry accepts such a configuration of vessel, it could set the precedent to extend the length of navigation locks along the Seaway while maintaining existing width and depth at each lock. To modify the Snell and Roosevelt navigation locks near Massena NY, American authorities may seek to negotiate to have larger vessels transit through the Welland Canal into Lake Ontario to the terminal at Oswego NY where there may be scope to build additional storage for American agricultural produce intended for export to overseas markets.
Bow Waves and Wakes
One of the complaints voiced by citizens who own waterfront property along the St. Lawrence River pertains to erosion of their property caused by bow waves from passing ships. While sailing at reduced speed reduces the height of the bow waves, sailing at excessively low speed reduces operational feasibility. Experiments undertaken in the southern USA involving twin hull vessels involved reshaping the bow area to redirect most of the bow wave to pass between the twin hulls and also partly under the vessel, with a residual bow wave of one inch (2.5cm) for a barge size of vessel.
During an earlier time, a discussion on bow wave reduction focused on the theoretical possibility of sailing slightly deeper and wider ships through the Suez Canal, using bow wave deflection techniques. There may be scope to undertake scale model research in Canada involving retractable bow wave deflectors that when deployed, would form channels along the ship’s hull to redirect the bow wave rearward, perhaps assisted by bow area propellers. Deflectors would be retracted and raised above deck upon approach to each navigation lock, reducing ship sailing beam from 105 feet to 78 feet.
The citizens who own waterfront property along the Upper St. Lawrence River and around Lake Ontario seek reduced water levels and reduced bow waves from ships as a means to protect their property. At the same time, the viability of the inland waterway transportation sector depends on elevated water levels between Lake Ontario and Montreal, to allow Seaway-max size of ships to sail at peak payload. Lengthened vessels could carry the same payload in shallower water and extreme extended length vessels would likely carry greater payload while sailing through the same shallower water depth.
The addition of bow wave deflector technology offers the promise of reducing ship bow waves, with the possibility of ships being to sail at slightly greater speed. One possible future option would be for Seaway authorities to lengthen the basins of navigation locks to transit longer vessels of equivalent width and sailing depth as present Seaway-max ships. Environmentalists opposed an earlier proposal to deepen (to 33 feet), widen (to 110 feet) and lengthen (to 1,200 feet) the navigation locks along the Seaway to allow older generation Panamax ships to sail into Lake Ontario.
The domestic Seaway ship transportation sector and the citizens who own waterfront property along the Seaway need to find a basis for possible agreement that combines lower water levels while ships move freight. Extended length coupled ships that sail in shallower water depth and produce a smaller bow wave while carrying equivalent or additional payload represent one possible option. A shipbuilder capable of modifying older ships into barges is located along the Lower St. Lawrence River across from Quebec City.
The opinions expressed herein are the author’s and not necessarily those of The Maritime Executive.