2020 was a crazy year for Carnival Corporation (NYSE:CCL)(NYSE:CUK) beginning with an 80% plunge, and ending up with a loss of "only" 57%. But there's a silver lining for investors today: Buy Carnival stock now, and if the share price just goes back to where it was before the coronavirus crisis hit, you've got yourself a clean double.

Or so the thinking goes.

And that may be thinking right.

Cruise ship at sea

Image source: Getty Images.

Let's run a thought experiment, shall we? Right now, after its big dip and its partial recovery, Carnival Corporation stock carries a market capitalization of $22.9 billion. Over the five years preceding the pandemic, Carnival averaged profits of about $2.7 billion per year, according to data from S&P Global Market Intelligence. So if you assume that at some point in the future things will get "back to normal" for Carnival (and I do), then the stock currently costs a low 8.5 times normalized earnings.

That's less than half the 18.7 P/E ratio the stock has averaged over the last decade. And it suggests that there really is a case to be made for Carnival stock doubling once things get back to normal.

The bigger question is how long it will take to return to normal, and whether Carnival Corporation has enough cash to survive until cruising resumes and customer interest returns, so that it can get back to making the kind of profit used to make.

But there's good news on that front, too. After running the numbers on Carnival, I estimate the company has something on the order of $14.2 billion in cash available to it right now. Even at a monthly cash burn rate of $530 million, this implies that Carnival has sufficient cash to keep itself afloat through about March 2023 without needing to sell any more stock or take out any more loans.

Will that be long enough? The best estimates I've seen suggest cruising in the U.S. won't start up again before April or May -- and even those cruises will be of limited duration and with limited passengers on board. We can't expect a full return to normal, I suspect, until vaccines have been widely distributed across the U.S., and experts aren't expecting that to happen before summer.  

Still, even if cruising isn't back to normal before the end of this year -- or even next year -- it will return to normal eventually, and surely before Carnival runs out of money in early 2023. If you can afford to be patient, I see a real opportunity to earn a double on Carnival stock within the next three years.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.