You are reading this on the Internet. You may, in fact, make a living online and never need to leave your town. Distance may seem an abstraction when you can talk to anyone on the planet (or in orbit of it!) in real time, or fly almost anywhere within 24 hours. But as long as you need food to eat or clothes to wear – or the electronic device you’re using to read this – geography and distance will continue to have a substantial impact on your ability to to fill those needs.
Which is a roundabout of saying, the ocean is really BIG.
How big is it?
A straight shot from San Diego, California, to Tokyo is a bit over 5,600 miles (9,100 km). This will take you 14 days at 15 knots.[i]
Sailing from San Diego to Brisbane, Australia, will cover 7,200 miles (11,600 km) and take 18 days at the same speed.
London to Hong Kong, via Suez, is a voyage of more than 11,000 miles (18,000 km) and requires 27 days to complete at an average speed of 15 kts.
If the Suez Canal was shut down, the same trip would be 15,000 miles (24,000 km) and 37 days. So let’s hope the canal doesn’t have any issues.
But here’s the part that might shock people of the modern technological age: These numbers have been static for 150 years. As far back as the 1870s, ships were winning the unofficial “Blue Riband” for Atlantic crossings with speeds averaging 15 knots. By 1952, the final Blue Riband winner, the passenger liner SS United States, edged the competition with an average speed of 34.5 knots, crossing from the United Kingdom to New York City in 3 days, 12 hours and 12 minutes. But no (non-nuclear) ship can sustain such speeds for very long. This graph is why:
In general, this asymptotic curve represents every situation in which friction is fighting your efforts – it takes progressively more and more energy to add marginally less and less velocity. Even skydivers hit terminal velocity, where wind resistance keeps them from plummeting any faster even though gravity wants to keep accelerating them at 9.8 m/s2. I propose that we change the term to “asymptotic velocity” and then make that into the name of a rock band. It would be awesome. But back to our point, which is:
Water is much thicker than air. Friction is correspondingly greater.
Three-and-a-half days at 34.5 knots might work for a big ship with plenty of room for the oil bunkers, but they’d never make it across the Pacific at that speed. Even a vast 50,000-ton ship like the United States would run out of fuel.
So a more moderate speed it is – and somewhere in the teens or maybe low twenties in nautical miles per hour[ii] is where you’ll find most transoceanic ships’ sweet spot combining speed and fuel efficiency.
And thus, a trade route or war plan conceived in 1910 is still going to be about the same as today. Except for the occasional addition of a canal, the choke points don’t change. Key ports don’t appear or shut down all that often. Places that mattered to William McKinley generally matter to us now. Check out this graphic from 1938, courtesy of the University of Texas – there’s not too much that needs updating (though the lack of mainland Asian ports like Shanghai or Pusan is a question mark). Things have changed a bit since then, but cities and islands are still right where they used to be. And ships crossing the vast spaces between them are no faster than they were in the coal era.
Ships themselves will always be improving, getting safer and more efficient. Nevertheless, they remain prisoners of geography and physics. The world may feel smaller when I can write this in Bahrain and you can read it the same day in North America – but the time it takes to sail that gulf is the same as it has been for decades, and will be so for decades to come.
***Blog Bonus!!!*** I discovered a Hostra University professor’s transportation maps while researching this post. They accompany a textbook. I didn’t directly reference it anywhere, but it was too good not to mention. Go spend some time there to learn about how the world is stitched together by transportation links.
[i] All these numbers are rounded, if you couldn’t guess.
[ii] A nautical mile is 2,000 yards. The term “knot” comes from the method sailing ships used to estimate their speed.