Why Are Battleships Called “BB”? The Curious Origin of a Naval Code

When looking at us naval history or games that has battleships, battleships in the U.S. Navy are named “BB” followed by ships name not “B” for battleship. From BB-45 USS Colorado to BB-35 USS Texas, the pattern is clear. But why did this happen in the first place?

The origin of U.S. naval hull classifications goes all the way back to the 1890s. At the time, the system was straightforward. Ships were simply listed by their type and number it was given.

Battleship No.1 – USS Indiana

Cruiser No.3 – USS Baltimore

This system worked until the fleet expanded, it became harder to manage. Long names weren’t ideal for official records or communication during urgent times.

That is why it was changed to follow the Alphabet like B-1, C-3, and more.

In 1907, the Navy began simplifying ship classifications using letter codes combined with numbers. This marked the start of the modern hull code system.

• The USS Indiana became B-1 (for Battleship 1)
• Cruisers were labeled C-1, C-2, and so on
• Armored cruisers used ACR
• Scout cruisers were CS
• Destroyers became D
• Torpedo boats: TB
• Submarines: S

These early systems mixed and matched differently as both full descriptions and short codes were used depending on the document or the context.

However, the U.S. Navy had grown dramatically during WW1, and ships became increasingly specialized with variants. To bring order to chaos, Secretary of the Navy Robert E. Coontz issued a standardized classification system that started on July 17, 1920. From that day forward, ships were labeled with a consistent code: the first letter indicated the ship type, and following letters specified its role or variant.

Examples where like

• DE = Destroyer Escort
• BB = Battleship
• CA = Heavy Cruiser (Armored)
• CV = Aircraft Carrier
• SS = Submarine
• DD = Destroyer

So Why “BB” for Battleship?

Here’s where it gets fun and a little absurd.

You might think a battleship would just be labeled “B”. But under the new system, every ship needed at least two letters. Some ships had specific sub-types, like escort or attack variants. But battleships didn’t their only job was to go in, shell the enemy, tank incoming firepower and dominate with heavy firepower.

As the legend goes, when someone asked:

“What’s the sub-type for a battleship?”

The answer was simple:

“There is none. Just write ‘B’ twice.”

And so, BB was born — not because it stood for anything fancy, but simply to fill the two-letter requirement. It’s a classic case of military logic at its finest.

Now as you see above the pattern continued to other ship like submarine and destroyer. This logic wasn’t unique to battleships. Other ship types followed the same rule. If there was No sub-type? Just double the letter. Simple, effective in the eyes of the navy.