Global Potential for Towing Icebergs

iceberg

By Harry Valentine 2017-05-14 20:47:08

A recent news story focused on a proposal to tow ice bergs from Antarctica to the Middle East to provide potable water for the drought stricken region. A project of this magnitude would most likely involve a steep learning curve and unforeseen problems. However, Canada's experience and the current drought in South Africa could give rise to opportunities to develop skills that could then be applied globally.

Canadian Icebergs

The idea of towing icebergs dates back to the latter 19th century when large steam powered ships entered trans-Atlantic service. However, serious towing of icebergs only began in very recent years and mainly as a means of redirecting icebergs away from shipping lanes. 

In the north Atlantic, the cold Labrador Ocean current and the cold Greenland current regularly propels iceberg south towards Canada’s east coast near Newfoundland and even into the Gulf of Saint Lawrence. The regular appearance of icebergs off Canada’s east coast provides opportunity to produce potable water for export.

At the present time, some parts of the U.K. are experiencing drought. During other years, parts of Europe have endured drought. The maritime distance between Newfoundland and the U.K. as well as France is much shorter that between the Antarctic and Cape Town. 

There have been occasions where cities along the Saint Lawrence Seaway including Montreal, have imposed water restrictions on their citizens due to summer drought. An industry in Eastern Canada that produces potable water from icebergs could carry that water in tanker ships, upstream along the Saint Lawrence River.

Trans-Atlantic Towing

The Greenland Current often pushes icebergs south along Greenland’s east coast where a team of future designs of super-tugs could intercept them and use cables to redirect them toward the North Atlantic current. Possible destinations would include Iceland, Ireland, the U.K. or France where the icebergs may be converted to potable water. Tanker ships would carry the potable water to the final destinations where the water would be urgently needed. 

In the South Atlantic, a portion of the eastward flowing cold South Atlantic Current joins the northward flowing cold Benguela Current that flows by Cape Town. There could be potential in the South Atlantic to use super tugs to redirect the movement of an iceberg from the South Atlantic Current into the Benguela Current before redirecting the iceberg toward the South African coast. 

However, the City of Cape Town dumps raw sewage into both False Bay as well as the southern area of Table Bay. That practice prevents possible conversion from iceberg into potable water at either location. The historical significance of Robben Island near Cape Town could prevent conversion from iceberg into water at that location. 

Iceberg Melting Sites

Deep water inlets, fjords and bays would perhaps represent the optimal locations to melt icebergs to obtain potable water. In the northern hemisphere, suitable locations are to be found along the northeastern coast of Newfoundland at Trinity Bay, White Bay and Notre Dame Bay while Iceland also has several suitable bays where deep draft tanker ships may drop anchor. Trinity Bay offers greater depth than any bay or inlet off the west coasts of Ireland or the U.K., or even Norway’s Trondheim Fjord. By default, Newfoundland’s Trinity Bay may be the optimal location to blow up and melt icebergs.

In the Southern Hemisphere, Argentina’s Cape Horn is close to the Antarctic and the proximity to Chile would require agreement from two governments in order for icebergs to be towed close to shore, between islands. However, water depth is much shallower that Newfoundland’s Trinity Bay. 

Near the southern tip of Africa, the north end of Saldanha Bay had sufficient depth for bulk carrier ships, except that icebergs would have to be blown up into smaller pieces to be towed into that bay. South Africa’s recent drought makes towing icebergs a possible future option to obtain potable water.

Future Technology

There would likely be a future need to transport massive volumes of water to regions that experience drought. At present, the largest super tankers can carry 320,000m3 of oil or 256,000m3 of potable water that would represent some 10 days of usual water consumption for a city of one million people. With water restrictions in effect, that volume of water could last for up to 15 days. 

Maritime structural designers would need to explore the future possibility of a coupled two-section tanker ship, perhaps using a coupling that would allow for relative yaw and pitch between the leading and trailing sections. 

At the present time, the need to tow icebergs is comparatively rare, allowing the present generation of teams of tugs to undertake the task. A future increase in iceberg towing could warrant the development of automated, submersible super-tugs that may perhaps be powered by (thorium) nuclear reactors. 

Teams of coordinated, automated submarine-tugs sailing at different depths could push an iceberg in a way to minimize rollover and travel parallel to ocean currents over extended distances. The cost of such technology would have to be compared to the cost of other technologies that can provide potable water.

Conclusions

Several regions around the world will, in the future, need to provide greater volumes of potable water to expanding populations. Part of the increasing demand is driven by population growth, while unpredictable weather patterns are causing multi-season drought in many regions. 

Technologies that can provide potable water include water-from-air extraction technology that is suitable for humid locations, desalination of seawater, increasing atmospheric humidity upwind of coastal mountains and transportation of water from other regions. Towing icebergs is one of several future options.

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

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