OP-ED: Prospects for Oceanic Ship Trains

By Harry Valentine 2012-11-20 15:19:00

By Harry Valentine

The history of oceanic transport involves initiatives that date back over several centuries to improve productivity in the form of carrying more cargo while using a smaller crew and making more efficient use of available energy. There is potential at the present day, to further explore possibilities as to how to enhance the future productivity of maritime transportation. Such exploration would involve proven methods that have been well-tested using scale models that have been repeated subjected to real life conditions in laboratories.

There are occasions when real life conditions may duplicate methodologies that are usually confined to marine laboratories. Such is the case with the barge trains that operate along the Mississippi River and several of its tributaries. The idea of building barges with notched sterns that each includes a pair of large bumpers, may have originated in a laboratory where a line-up of such barges may have been coupled together like a railway train. Except that the coupling system allowed the barge train to operate like a straight ship that would be propelled and steered from the stern of the coupled system.

The barge trains that operate along the Mississippi system may be viewed as real life scale models that have been proven and refined over a period of many years of successful operation in a real world maritime laboratory. Over a period of many years, the Mississippi barge trains have periodically encountered waves on the river, sometimes caused by other watercraft and sometimes caused by severe winds that blow along the river. These occurrences from a real life laboratory involving craft the fraction of the size of oceanic ships, provides a technological precedent that may be scaled up to involve ocean going ships.

On the river, a trailing barge sails in the hydraulic shadow of the barge coupled immediately ahead of it. That arrangement reduces water drag at the bow of the trailing barge. On the ocean, over 80% of the power of a ship propeller is used to overcome hydraulic drag at the bow of the ship. A coupled train of 3 to 4-ships could theoretically reduce energy consumption by 40% to 60% over the same number of ships sailing independently across the ocean, from nearby ports of origin to nearby ports of destination.

Trans-Arctic Ship Trains:

In the not too distant past, a merchant ship was allowed to follow a Russian icebreaker ship on a voyage between the Norwegian Sea and the Bering Strait. The trans-Arctic sailing conditions require increased engine power to push a ship through snow packed waters. By comparison, a coupled ship train would combine the engine power of several ships that could push the higher hydraulic drag imposed on the bow of the single lead ship sailing through Arctic waters. The train would operate like a straight ship with computer-assisted control of power and navigation.

When the train needs to change direction, computer control would steer rudders to different angles or operate bow and stern thrusters at different rates at different points along the train. Computer control would also regulate power and thrust at various propellers located under the train. For trans-Arctic sailing, there may be scope for the shipbuilding industry to develop a buoyant icebreaking attachment that would be coupled to the bow of the lead ship. The attachment may include electrically driven machinery that could help break up the ice ahead of the ship train, Regular discharges of compressed air under the ice cover, from subterranean caverns would further assist in breaking a path through the ice.

The shipbuilding industry will also need to explore prospects of developing a buoyant coupling technology that could attach between the stern of a lead ship and the bow of a trailing ship. That coupling technology would need to be designed to keep a large cross section of the bow of the trailing ship in the hydraulic shadow of the leading ship, as a means to reduce fuel consumption. Such technology may be applied to several ships that originated from the same shipyard and that are owned by the same shipping company.

There may be potential in the future, for a shipyard to build groups of ships with a notched stern that includes bumpers to allow the bow of a trailing ship to push against the stern of the leading ship. The precedent for such a concept is well proven on the Mississippi River barge trains and may greatly assist in seasonal trans-Arctic ship transportation. At one end of the voyage are the “nearby” ports of Seoul, Tokyo and Shanghai while at the other end of the voyage would be several “nearby” ports located around the North Sea and the Baltic Sea, including Rotterdam.

Conclusions:

The precedents developed in smaller scale in the real life marine transport laboratory along the Mississippi River may serve as the basis by which to develop oceanic ship trains. Such trains could reduce fuel consumption and operate with a smaller crew than several independent ships sailing a parallel journey. As well, the combined power and thrust that would be possible from coupled ship trains would greatly assist on trans-Artic voyages. Ships that operate that route could incur a competitive edge in the area of international trade.

____

About the Author

Mr. Valentine holds a degree in mechanical engineering from Carleton University, Ottawa, Canada, with specialization in thermodynamics (energy conversion) and transportation technology.
He served as a research assistant to Dr Ata Khan, professor of transportation engineering who is still on staff at Carleton University.  Mr. Valentine has a background in free-market economics and has worked as a technical journalist for the past 10-years in the energy and transportation industries.

Over a period of 20 years he has undertaken extensive research, authored and published numerous technical articles in the field of transportation energy.  His economics commentaries have included several articles on issues that pertain to electric power generation.

Mr. Valentine has technical journalistic experience covering low-grade and high-grade geothermal energy, steam generators (with continuous blow down to keep the boiler water clean), engine exhausts, solar thermal (low-grade and low-grade thermal), nuclear and coal-fired thermal steam-power stations.

 

MarEx does not necessarily endorse any opinions herein.
 

The opinions expressed herein are the author's and not necessarily those of The Maritime Executive.