Why Do Some Ship Names Have the Prefix "SS?"

You've probably heard of the ship designation SS, but what do those letters actually stand for? Find out here.

Why Do Some Ship Names Have the Prefix "SS?"

Many people are aware that vessels, generally of the larger variety, tend to start with a prefix, with that prefix being the letters "SS." Avid fans of a particular Nintendo franchise may also be familiar with the SS Anne, which has actually colored a lot of perceptions of ship names.

A lot of people would tell you that all ship names start with the letters SS. It just sounds right and natural. But what if we told you that this is not actually the case? That there are almost no ships out there today that start with the letters "SS?" Not only that, but there haven't been many ships with this prefix in a very long time.

This may come as a shock to some of you, but don't worry: we'll explain everything you need to know about this outdated prefix, and why it is well-known in popular media even though that prefix isn't used much if at all anymore.

The Prefix "SS" is Actually a Designation

As you may have guessed prior to now, the letters that precede a ship's name do actually have meaning, and they aren't random at all. Their primary purpose is to designate what type of ship a vessel is, and what purpose that vessel serves. Usually, the ship's full name actually includes the spelled-out version of these designations.

For instance, you may be familiar with the designation "USS," which is used with United States Navy vessels. This designation stands for "United States Ship." So the full name of the USS Arizona was "United States Ship Arizona." But that's a big mouthful to say, so it is shortened to USS Arizona. The prefix describes the vessel's allegiance.

Similar prefixes that designate a military vessel's allegiance include HMS (Her Majesty's Ship) for the Royal Navy of the United Kingdom, as well as IJN (Imperial Japanese Navy) from World War II. However, the majority of ship designations are not actually for military vessels. SS, for instance, does not have anything to do with a country's navy.

That's because most ship designations exist to specify how a ship is powered or what its specific job is. In the case of the designation "SS," that stands for "steamship." This designation serves to specify that a vessel is powered by a steam engine, though SS can, in some very rare cases, refer to "single-screw ship" as well.

That said, nine times out of ten, SS would mean "steamship." As you may imagine, this term doesn't receive much use these days, as there are almost no operating steam-powered vessels left in the world. But in the early 1900s, steam power was a major means of ship propulsion, so this designation had much more relevance.

Why Did Designating Propulsion Systems Matter?

Technically, it wasn't all that important, but when it was not a given that all vessels were steam-powered or better, it actually mattered to people what type of propulsion system a boat had. Designating that a vessel was steam-powered automatically told people a few crucial things about it.

One, the vessel almost certainly required more power to sail than a sail or a rowboat. And two, it was almost certainly faster than those options as well. This would be important for logistics and organization, as the people in charge of dockyards, mail, cargo transport, and more would want to know what types of ships they are dealing with.

Of course, you could always just ask someone, but that's a lot of hassle, especially if you are on a tight schedule or have many ships to deal with. Simple, easy designations like "SS" tell people what they need to know about a boat swiftly and efficiently, at least in this regard. It's much easier than trying to figure out what type ships are without those prefixes.

These days, designating the means of propulsion for a vessel isn't really that important, since technology is pretty comparable now for the most part. The vast majority of ships use the same type of propulsion and the ones that don't are usually very niche vessels with specific designations letting people know.

What Are Some Other Common Prefixes for Ships?

SS may not be in use much these days, but there are many other prefixes that you may have heard before. Nowadays, a prefix generally serves to let people know what kind of job a vessel does. Here are some prefix designations commonly used today:

  • SV -Sailing Vessel
  • RMS - Royal Mail Ship
  • TS -Training Ship
  • MY - Motor Yacht
  • CS - Cable Ship
  • GTS - Gas Turbine Ship
  • LB - Lifeboat
  • MT - Motor Tanker
  • PSV - Platform Supply Vessel
  • NS - Nuclear Ship
  • RV - Research Vessel
  • MV/MS - Motor Vessel/Motor Ship

Now, all of these prefixes seem to imply that every ship out there must have one. But you've probably noticed that a lot of boats have no prefixes at all. That's because designations such as these aren't a part of maritime law or anything. They were mostly used in the past for efficiency related to means of propulsion.

Military navies still use many prefixes in order to establish the roles of ships within their hierarchy. But that level of organization isn't really needed when it comes to most civilian vessels, so there is no real reason to add such designations to boats in most cases. They are still used sometimes, but it's not all that common.

So, if you see the prefix SS attached to any ship name, chances are, you are reading about an older vessel that is not being used anymore. However, if you are looking at a ship still being sailed today, you may be looking at a designation that means "sailing ship" or "single-screw ship," though both of those are pretty unlikely.

As for why most people know about the SS prefix but none of the others, that's a matter of many movies, shows, and books taking place around the time that SS was a common designation for ships.