Anyone who was born and lives by a ship canal naturally takes a little extra interest in these highways of the sea. Locking systems are a source of wonderment to any small boy and many an engineering or maritime career must have been instigated by an afternoon watching vessels rising and falling as if by magic.

The Panama Canal was opened in the same year as the Houston Canal, 1914, so it is very natural that there should be a particular Texan fascination with Panama.

Canals are, of course, almost as old as civilization. The early examples for irrigation in the Middle East, later for drainage in Europe, finally becoming the forerunner of the railroads - a long distance transportation system in their own right, for just a short while before rail and later the internal combustion engine often drove them out of business altogether.

What isn't obvious is that ship canals come in two varieties, with very different functions. Some were designed to link inland manufacturing centers to the sea - Manchester being a prime example. They were simply made big enough for seagoing ships to reach the city itself, saving transshipment.

Others were designed to provide a short cut across an isthmus and to reduce a sea voyage by anything from a few miles to many thousands. It is not by accident that the Panama Canal seems so important to Americans - it was finished in the year when Europe exploded into war, and when the necessity to move naval vessels from Pacific to Atlantic quickly seemed very real.

Most of the great ship canals that crossed an isthmus were seen as having important military significance. This history has clouded the true commercial importance that can be, as all things mercantile, rather more short-lived.

Unlike navies, commerce is only interested in moving ships from one place to another as a means to the end of moving cargo.

To the trading community a canal is only a method of connecting two transport systems together; the fact that the systems happen to be ocean systems and canals are full of water is merely a useful coincidence. The location is important, but merely as the point where the two ocean systems come most closely together, not necessarily because it is a good place to have a canal.

As it is usually the shortest way, the canal course is usually the optimum route for road and rail too with the line of the canal followed by road and rail links, and with a port facility at either end.

If at any time, the cost of unloading cargo at one side of the isthmus, transporting it by road or rail and reloading to ship at the other, falls below the cost of transporting by vessel transiting the canal, land transportation will be used. The canal will start to fall into disuse. This has happened many times in history.

Indeed the restriction on the maximum size of vessels that can use the canal is already pushing unit costs up on traffics using the all water route. This too has closed canals many times and in many places.

So the ports at either end of the Panama Canal may have more significance in the future than the canal itself. The can be natural transfer points for moving cargo on sea-land-sea transfers. The freight container makes this quick, cheap, safe and easy. These ports can take larger vessels than the canal can manage. They can become hub ports for the area around them and handle cargo that will never enter Panama except as a transshipment point.

And now the unkindest cut of all...

Once we realize that the only significance to trade is the cost of moving cargo from Pacific to Atlantic and vice versa, we wonder if there are any other cheaper routes. There may only be one canal linking the two great oceans, but there are a hundred hungry ports and more each side - and a hundred, hundred potential routes.

...we take the atlas from the bookcase and begin to look at world with fresh eyes, just like that little boy at the lock gates so long ago.