You’ve read the title. Aircraft carriers of where​ powered by what​? I was just as surprised as you are, but yes, they really did exist. I now introduce you to USS Wolverine and USS Sable:

Left: USS Wolverine

Right: USS Sable

These two flattops served in the Corn Belt Fleet during World War Two, and featured such notable pilots as future US President George H.W. Bush. Their home port was Chicago, and through their years of US Navy service they never left the Great Lakes – they couldn’t fit through the locks of the Welland Canal that bypasses Niagara Falls. They used coal powered paddle wheels, which had been obsolete on navy ships for decades. And no, none of this is a joke or an elaborate engineering fiction story.

Wolverine and Sable were converted civilian ships, like most of the war’s “escort carriers” – in contrast to the faster and more capable “fleet carriers” that were all purpose built as navy ships. Escort carriers were named for their main role: escorting slower merchant ship convoys and using their planes to guard the merchant ships from enemy attack.

These two particular ships began life as luxury passenger liners sailing between ports on the Great Lakes. Wolverine, originally Seeandbee, plied the route from Buffalo to Cleveland beginning in 1912, while Sable, as Greater Buffalo, brought passengers and cars between Buffalo and Detroit starting in 1924. Both were propelled by coal-powered horizontal paddle wheels, which promised a smoother ride for guests compared to screw ships of the day. These paddle wheels were kept through their Navy service, making these ships the US Navy’s only coal fired carriers in its history.

Seeandbee as a passenger ship

Luxury passenger traffic on the Great Lakes slumped during the Great Depression, so as the US entered WWII and the navy was eager to get their hands on anything that floated, the ships’ owners were very happy to sell. Wolverine was the first of the two to be converted to a carrier, commissioned on August 12, 1942, while Sable followed on May 8, 1943.

One technicality does need to be mentioned: Sable and Wolverine were fully capable of launching and landing fixed wing aircraft, and indeed did so thousands of times per month while in service. Nevertheless, the US Navy didn’t officially classify them as aircraft carriers, since they didn’t have hangars for storing the planes. All the planes they were carrying had to be stored on the flight deck.

So if Wolverine and Sable couldn’t carry that many aircraft, they wouldn’t be all that useful for, say, a surprise raid on Sarnia, Ontario. Thankfully, the US and Canada were fighting on the same side of the war so it never came to that. And while Axis submarines did sink plenty of cargo ships in the waters near North America, they certainly never made it as far as Lake Michigan. But then what were these carriers used for so far from the front?

Well, precisely because they were so far from the front, they were the perfect training ships. The US Navy operated dozens of seagoing carriers during the war – both fleet carriers and escort carriers. Each one was a significant military asset operating in potentially dangerous waters. Aviators could train for carrier landings on Wolverine and Sable where the risk was lower, and be ready to fly on the rest of the Navy’s aircraft carriers.

A crashed plane on Sable’s deck

So it didn’t matter that there wasn’t space for many aircraft on the two ships of the Corn Belt Fleet (an unofficial but popular term). Ideally, every pilot that landed would take right back off again. The deck spaces were only needed if an aircraft was damaged during landing. They’d fix the planes when the ships returned to Chicago. And yes, President George H.W. Bush was one of the pilots certified on Sable – one of over 17,000.

World War Two saw countless crazy new ideas from every corner. Their success varied widely. Some never made it to combat, like bat bombs or ships made of ice. Some never reached their claimed potential, like German super-tanks or the Norden bombsight. And some changed the world forever, like the ballistic missile and the atomic bomb. Compared to some of these, turning a couple coal-fired paddle steamers into makeshift freshwater aircraft carriers seems downright ordinary and sensible.

Coming soon: The “ABC’s” were almost the “ELH’s”