Recently I was thinking about how in the first Pirates of the Caribbean movie The Black Pearl was claimed to be the fastest ship ever and the HMS Intercepter was the fastest ship in the royal navy, and in one scene The Black Pearl is easily catching up to the Interceptor. I understand that these are fictional vessels, but I still didn’t understand how one could be considerably faster than the other, when I can’t really tell the difference between the two designs(to the untrained eye, you wouldn’t be able to tell which one is faster by looking at it.) How is one ship so much faster than another ship that appears to be designed very similarly?
(Edit: thanks, i have a bit better understanding of what can cause this, thank you to everyone who has commented, although feel free to elaborate or provide additional explanations if you wish!)
In: 65
There’s an interesting characteristic of boats called the _hull speed_.
As a boat moves through the water, its bow creates a wave. The faster the boat goes, the longer the wavelength of the bow wave gets. At some speed, the wavelength of the bow wave is equal to the length of the boat itself. The boat is effectively stuck in the trough between two wave crests. The speed at which this happens is the bow speed.
For a lot of boats, that’s a limiting factor. The amount of energy needed to go faster goes way up, because the boat has to climb out of that trough that it’s stuck in.
If the boat has a lot of surplus power, like big engines or lots of sails and plenty of wind, it can climb out of the trough and start planing. You may have seen this with motorboats, where the front part of the boat isn’t even in the water.
The TL;DRBI5 is that a long boat can go faster than a short boat, and a boat with more power (like more sails) can go faster than a boat with less power.
Latest Answers