Do you remember the old cars from the early 1900’s that did not actually have a starter? I know you are not that old but you may have seen pictures or antiques at the fair (so get off my back!!).
You got out your crank, you stuck it in the hole and turned the motor until it started.
How about doing that with a World War II 690 horsepower German Tiger Tank! Apparently the batteries were not that reliable, so in cold weather this was how you started it.
Here is a video, it is not English but you get the idea. You can find the history and the specs here.