Note 417 — Chapter VIII · —Coast Peoples

With the recent increase in the size of vessels, two contrary effects are noticed. In the vast majority of cases, the inner edge, as marked by ports, moves seaward into deeper water, and the zone narrows. The days when almost every tobacco plantation in tidewater Virginia had its own wharf are long since past, and the leaf is now exported by way of Norfolk and Baltimore. Seville has lost practically all its sea trade to Cadiz, Rouen to Havre, and Dordrecht to Rotterdam. In other cases the zone preserves its original width by the creation of secondary ports on or near the outer edge, reserved only for the largest vessels, while the inner harbor, by dredging its channel, improves its communication with the sea. Thus arises the phenomenon of twin ports like Bremen and Bremerhaven, Dantzig and Neufahrwasser, Stettin and Swinemünde, Bordeaux and Pauillac, London and Tilbury. Or the original harbor seeks to preserve its advantage by canalizing the shallow approach by river, lagoon, or bay, as St. Petersburg by the Pantiloff canal through the shallow reaches of Kronstadt Bay; or Königsberg by its ship canal, carried for 25 miles across the Frisches Haff to the Baltic;417 or Nantes by the Loire ship canal, which in 1892 was built to regain for the old town the West Indian trade recently intercepted by the rising outer port of St. Nazaire, at the mouth of the Loire estuary.418 In northern latitudes, however, the outer ports on enclosed sea basins like the Baltic become dominant in the winter, when the inner ports are ice-bound. Otherwise the outer port sinks with every improvement in the channel between the inner port and the sea. Hamburg has so constantly deepened the Elbe passage that its outport of Cuxhaven has had little chance to rise, and serves only as an emergency harbor; while on the Weser, maritime leadership has oscillated between Bremen and Bremerhaven.419 So the whole German coast and the Russian Baltic have seen a more or less irregular shifting backward and forward of maritime importance between the inner and the outer edges.