The harbor in St. Thomas was popular among merchants and trading companies for its good facilities: the West Indies’ largest floating dock, good machine shops, clear channel marking and inexpensive harbor fees. But it was also notorious for two problems: hurricanes and diseases, particularly yellow fever and cholera. In the 1800s, an average of 2000 – 3000 ships came annually to St. Thomas. In the 1860s, this increased to 4600 annually.
About half of the tall ships arrived from Caribbean ports and a quarter from European ports. Vessels under the Danish flag made up a smaller and smaller share. In the 1820s, it was twenty-three percent; in the final year before the sale in 1917, it was only thirteen percent. Most ships in the 1820s sailed under an American flag, but in the 1910s British ships had become completely dominant.
The vessels in the harbor became larger and larger. In the first half of the 1800s, the average tonnage2 increased from 60 to 100 metric tons. From the 1820s to 1916, the total tonnage increased from 150,000 to 900,000 metric tons annually. In 1823, the first steamship ever put in to St. Thomas – a small North American steamer. From the 1860s onward, steamships came to the fore in earnest, and in 1864 they accounted for ten percent of the tonnage in the port.
The First World War puts a stop to increased shipping traffic
In order to hold their own in international competition, extensive improvements were made to the harbor by the Danes at the start of the 1900s. The basin was deepened, wharves were constructed and conditions were generally improved. There were great expectations for the increased traffic that would pass the Danish colony on the way to and from the newly-opened Panama Canal. However, the outbreak of the First World War in 1914 frustrated all expectations, and the colony was sold to the United States in 1917.