While by the 1930s, diesel engines were revolutionising rail transport, and giving birth to a burgeoning flight industry, on the sea and on rivers, steam was still king. Unlike with trains and aircraft, large ships remained in service for decades, meaning that many of the ships that transported passengers of the 1930s were built as early as the 1850s, and some ships built in the 1930s remain in service today.
The steam turbine, first turned to use in seagoing vessels in 1897, was able to produce far more power than a traditional reciprocating steam engine. By the 1930s, all large ships were being built with such engines, allowing unprecedented speeds. For ships built in the thirties, the most popular fuel for running the boilers was no longer coal, but fuel oil. This meant that modern ships could run with a much smaller crew than earlier vessels. A typical small passenger steamer would have no more than a dozen crewmen, including a few stewards and cooks for the care of passengers. Larger vessels of course could have hundreds of crewmen (The Queen Mary, launched in 1936, had over a thousand), and were almost like floating towns, the crew forming their own community below decks.
Steam ships were used to ferry passengers between all major sea ports, and most navigable rivers were also serviced by ship. Such ships came in all shapes and sizes, from tiny paddle steamers, which could carry no more than a dozen passengers, to more modern screw driven steamers, which could carry hundreds of passengers in total luxury. The variety, diversity, and ubiquity of steam ships through the decade makes a detailed description by area almost impossible. It can be assumed that for most regions throughout the 1930s, if the region was accessible by water, and had any kind of population, then a steam ship would go there.
Passengers on ships in the 1930s could come from any walk of life. Immigrants to the USA (less common in the 1930s than in previous decades) would pack into giant transatlantic steamers, while more wealthy passengers could enjoy hotel-like conditions in first-class cabins. Outside America, river networks were frequently the backbone of trade in developing nations, and such rivers were packed with ships carrying all kinds of passenger, from native labourers to wealthy foreign investors.
For the duration of the 1930s, passenger travel across the Atlantic was conducted almost exclusively by sea. Whether travelling in the greatest luxury, or sweltering in steerage class, anyone wanting to travel between America and Europe would almost certainly do so by sea.
Following WWI, several of the largest German "superliners" (large ships designed and used for transatlantic passenger shipping) were transferred to America and Britain as war reparations. Of these, the Mauretania - the holder of the Blue Riband for the fastest transatlantic crossing for a twenty-year stretch ending in 1929 - is surely the most well known. Under new management, these huge ships continued to serve the transatlantic route. Travel aboard such vessels was glamorous and popular for many passengers the journey, and the style in which that journey was conducted, was as important as the destination. For first class passengers, the experience can best be compared to a modern cruise ship: meals, entertainment, sightseeing and socialising were all taken care of by the ships' staff.
By contrast, the conditions experienced by passengers in steerage (the hold of the ship) could be miserable. Before the United States closed its borders in the 1920s, immigrants to America would sleep packed together like cattle, eating a common meal that was described as frequently almost inedible.
New ships built in the thirties achieved even greater speeds. Two German ships, the Bremen (named after its home port) and the Europa were the first to challenge the Mauretania's dominance, but throughout the decade the Blue Riband continued to change hands. The ships competed not only for speed, but also for glamour. With the transatlantic route no longer dominated by immigration to the United States, ships built in the �thirties were designed as much for elegance as for speed. Competition was fierce, as several of the largest companies (including White Star, of Titanic fame) were operating at a loss for the first half of the decade.
From the 1860s onwards, steam powered icebreaker ships were developed, which allowed unprecedented exploration of the Arctic. Icebreaker ships rely on speed and strength to run their bow up onto a sheet of ice, and then break down through it. Steam power proved ideal for such a task. It was not until the start of the 20th century, however, that such ships saw regular service. The Klondike gold rush caused a surge in Arctic exploration. Union Steam Ships, with their characteristic black and red funnels, regularly serviced the Canadian and Alaskan coasts, even running tourist cruises from warmer southern ports into the frozen north.
With few regulations, large profits to be made, and steam ships becoming ever more ubiquitous and affordable, the thirties saw a proliferation of small-scale operations. None were more small-scale than the tramp steamer. Operating as a one-ship company, tramp steamers worked to no fixed schedule, going wherever there was money to be made. In the colonies, a great deal of shipping was conducted by tramp steamer, rather than by regular lines. While most tramp steamers were freight ships, they would not have turned down paying passengers, and indeed anyone with sufficient finances could charter a steamer to almost anywhere in the world.
Operating on a shoe-string budget, and often dodging regulations and taxation, tramp steamers often existed in a grey area on the edge of civilisation, and the law. The crews of such vessels could hail from any country, and tramp steamers often hired crew who could not find work elsewhere. Tramp steamers were romanticised even in their own time as an adventurous lifestyle, and they were the setting of many a pulp novel. While the reality was frequently much more mundane, tramp steamers were still an exciting part of the decade.
A Cult Afloat: The crews of tramp steamers were often drawn from the most remote and exotic ports, and lived their lives isolated from normal conventions or authorities. In such circumstances, the worship of strange ancient gods could take hold among a crew, who due to their itinerant lifestyle could commit all kinds of awful crimes without discovery. There are still many unexplored or forgotten places left in the world, accessible only by sea, and such places could be a haven for such cults. Worse, in the holds of giant passenger liners, crews might spend weeks or months at sea. Miles from land, the passengers would be at the mercy of whatever unspeakable ritual the cultists wished to perform.
The Ghost Ship: Stories of ships found drifting, seemingly abandoned, and yet perfectly seaworthy, have chilled sailors since the discovery of the Mary Celeste in 1872. Such a mystery could attract significant interest from investigators, and if the ship's route could be determined, an expedition might be launched to discover the fate of the crew. If such a voyage lead into dangerous, uncharted, or infrequently travelled waters, a party of hearty souls would be required for the job.
Strange Visitors: The US and Great Britain were paying increasing attention to border customs and immigration during the thirties, but smuggling remained rife. Criminal organizations that had cut their teeth in the prohibition era remained in operation, smuggling more illicit goods. Eldritch substances in the wrong hands could find their way onto the streets, as a new kind of drug. Worse, with the US imposing ever stricter regulations on immigration, the thirties saw the birth of people-smuggling into the United States. An old-world cult, or some degenerate tribe from the colonies, could find entrance to the States through one of the many ports along its coastline.