When considering the transportation sector’s environmental challenges, it is important to be aware of shipping.
There are over 93,000 registered ships worldwide providing a potential total carrying capacity of approximately 1.8 billion tons of cargo, and although this sector is making some efforts to go greener, there is still no clear route to achieving a sustainable solution. Here are some of the ways that are being looked at or progressed.
Many shipping companies are changing the engine fuel from oil based, to gas. The gas is obtained from natural sources and is a mixture of methane and ethane. It is stored as a liquid on the ship at a very low temperature, known as LNG (liquid natural gas) and then brought back to ambient temperature before being injected into the engine. The benefit of this method is a cleaner exhaust and is judged to be environmentally neutral. In the short term this is probably the best solution.
Development of this option is still in the early stages, and there are still some important challenges to be overcome. Firstly, the size of the fuel cells and the size of the electric motors needed are big challenges to be overcome.
Secondly is the storage of the hydrogen which is a long-standing issue. The current favoured method is to use liquid ammonia, which is then heated to release the hydrogen. This gas is then passed into the fuel cell where it mixes with oxygen from the air to produce water, and the spare electrons from this merger are thrown off and collected to become the electrical energy. The negative side of this process is that a poison gas, nitrogen-oxide may also be formed when the ammonia is heated.
There are a few ships that are powered by nuclear fuel but there are serious questions when considering this on a larger scale. The main issue is what to do with the spent fuel, and there are questions as to whether they can travel through the Suez, and Panama canals because of fear of radioactive poisoning by some of the governments of the countries that these canals pass through. It is also highly likely that other harbours around the world will refuse entry for the same reason.
The Magnus Effect
There have been some trials using the Magnus effect, a natural phenomenon which was first observed by Sir Isaac Newton in 1672 and a prototype was developed and trialled in 1921.
This concept was derived from observing a cricketer making a side spin with the ball, or a footballer kicking the ball to make it turn to one side. For a footballer, this is done by kicking the ball squarely, but in a position away from the centre. The spin has the effect of changing the direction of the ball. On the trial ship, the ball was replaced by two tall spinning cylinders, as seen below.
The spinning cylinders draw the wind around them towards the front of the boat which causes a pressure difference (high pressure at the back, and low pressure at the front) and this pulls the boat forward.
This is the Viking Grace, a Finnish ship, which has been in service since 2013. Here there is one tall cylinder, positioned on top of the ship. It is 4m diameter and 24m high and was installed in 2017. The owners claim that it gives a cost saving fuel of 6.1%
Some are convinced that the way forward is to look back and return to using square rigged sailing ships. The problem with this proposition is twofold.
Firstly, the square-rigged design does not sail against the wind. This means that the ships must follow the old trading routes around the world which they can only sail at certain times of the year. For example, an area of high pressure sits in the Atlantic Ocean between America and North Africa causing the wind in the winter to blow eastwards towards Europe. This makes it impossible for these ships to sail westwards from Europe to America. It is only in the summer months when the high pressure reduces in size and moves westwards that a route becomes available which is to sail south near to the European coast and then to the west, skirting around North Africa. This makes transporting goods comparatively slow compared with modern day shipping and renders the solution incompatible with a just-in-time economy.
The second issue concerns cargo loading and unloading. The rigging interferes with cranes lifting goods in and out of the ship which limits the size of the individual load. Because of this, sailing ships cannot carry shipping containers. And this must eliminate them from any consideration for the future.
Here are my thoughts, and from it, my proposal. I am an experienced yachtsman, have been involved in sailing for over 30 years, and I am keen on new technology. If we look at road vehicles, many of the main components that are used have been copied from designs originally created for racing cars. We could do the same for shipping.
In sailing, there are always new developments for racing yachts, and the pinnacle of these are the boats used in the America’s Cup Challenge. These yachts have carbon fibre hulls, Kevlar sails and ropes that are incredibly strong, using a material called Vectran. But one key feature is that in recent years they have changed from being mono hulls to catamarans.
The Catamaran Cargo Ship (Cargo Cat)
My proposal is to take this concept and adapt it for commercial transport. Below is my design for a catamaran cargo ship.
This ship is 53m long with a beam (width) of 15m. The fore and aft sail arrangement makes the boat capable of sailing against the wind, typically to maximum of 45 degrees. This makes it possible to sail the Atlantic from east to west in wintertime, and travel faster with the aid of the on-board engines.
It can hold 10-40ft shipping containers and has two engines, shown here on the left in blue, one in each of the hulls.
These engines will drive the ship when there is insufficient wind, and in harbours they will give very good manoeuvrability. By putting one engine in reverse, and the other in forward, the ship will be able to turn almost within its own length. This ability, together with side thrusting motors will eliminate the need for tugboats to assist.
The other important reason for using a catamaran design is so that the dock cranes can access the holds to lift the shipping containers in and out without interfering with the ships rigging.
The ship can also have deck cranes to lift smaller containers in and out, which will be useful in smaller harbours where crane availability is limited. At the stern I have added a ramp which can be lowered for moving small loads on and off the ship and enhancing the possibility of using the ship as a roll on roll off hybrid ferry.
As a proof of concept, these ships could be used for transporting goods from a container port to the many smaller harbours we have scattered around the UK, greatly reducing the number of trucks on the road, and the associated pollution.
Concerned by sustainable shipping? You may be interested in Shipping and the Environment: Improving Environmental Performance in Marine Transportation (external) and Sustainable Power, Autonomous Ships, and Cleaner Energy for Shipping (external) and other fine green mobility books in our shop.
Maersk Line (https://commons.wikimedia.org/wiki/File:Emma_Maersk_(7099702853).jpg), „Emma Maersk (7099702853)“, https://creativecommons.org/licenses/by-sa/2.0/legalcode
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