Britannia Ruled the Waves

She did, in 1840. RMS Britannia was the first true ocean liner, the first in reliable service between England and North America.

As Peter mentioned, the commercial importance of reliable ocean transport would be difficult to overstate. If you've read any books about life on sailing ships, such as Two Years Before the Mast, two things stand out: First off, sailing ships typically didn't sail until they had a full load of cargo. Second, even if they wanted to sail, unfavorable winds could keep sailing ships in port for days or longer. The two factors probably ran together, because since a ship couldn't count on sailing at a certain date or time, there was no reason to sail until the ship was fully loaded.

The Britannia changed all that. While no ship is immune from weather, steamships were able to sail if the winds were not favorable. Schedules could be made and kept. Businessmen could make appointments from the other side of the world and keep them. Companies could compete for business with a reliable way to get their products to another continent.

Mariners are conservative, for good reason. It was another ninety years before commercial sailing vessels disappeared, which likely had something to do with the adoption of oil as a maritime fuel. But it all began, 175 years ago this month.