How Outlander Made Those Sea Journeys Feel So Incredibly Real 

Warning: This interview contains minor spoilers for the remainder of Outlander season 3.

What looks like an 18th-century wooden pirate ship is sitting in the middle of a parking lot in Cape Town, South Africa. It’s not just set dressing for hit show

; it\'s a “working ship,” which means it could actually sail on the water, for a stretch at least. I try spinning the wooden ship’s wheel on the deck, and it moves, but it wouldn’t actually help me steer. For that, you’d have to use a box down below, which would help you drive the ship like a car, because there are wheels attached to this baby. “It’s quite amusing,” actor Sam Heughan, who plays

\'s Jamie Fraser, says during filming for season three. “These boats are so incredible, so realistic, it just transports you. As soon as you get on one, and the sails open, you feel like it has a life of its own.”

, is one of three ships we\'ve seen this season on the show. The

is the ship Jamie and Claire (Caitriona Balfe) take to the Caribbean to find their nephew Young Ian, who is now a prisoner on the pirate ship, the

. But the rescue mission hits a snag when Claire is in turn shanghaied by British man-of-war, the

season three, which is based on book three of Diana Gabaldon’s

or, as Heughan says, “when the journey becomes more interesting than the destination.”

Neither Claire nor Jamie will go down without a fight. Watch a new episode of #Outlander this Sunday on @STARZ. https://t.co/GEqYWkh3e3 pic.twitter.com/9uxNnbVq8p

It\'s not easy or cheap to realistically portray ocean voyages. The production\'s first order of business was finding the right location. They considered the Caribbean itself and Hawaii, and studios with water tanks in Malta and Mexico. But they kept coming back to the idea of “stealing” the set from another Starz television show:

, which was equipped not only with the required water tanks, but also a recreated version of an 18th-century Caribbean town, and, most importantly, tall ships.

“It would have taken us five years—five seasons—to build all of this,” says executive producer Matthew B. Roberts while standing on the deck of the

nearby, the sound stages, the tanks, a lagoon, and a dock. “We came in and redecorated, repurposed everything, because their Kingston and our Kingston are about 80 years apart. Just by coming to South Africa, and utilizing this facility, and this crew, we were able to do this.”

—it lacks an actual bow and stern when it sits on the lot. (Those are added digitally.) The

appears to rest right next to the water tank. “We never actually filmed on the

,” Roberts says, “but we used it as a model for the visual effects when Jamie and Claire witness Young Ian being taken off the coast by pirates.”

Because Cape Town is experiencing a severe drought, no water is wasted for tank use—every drop has been here for the past five years, and it keeps getting recycled via a collection and filtration system. “People would get sick if they drank this water,” Roberts says, as we stand next to the murky tank. “It’s no good for drinking.” It is good, however, for shooting underwater scenes, which the producers monitor from above. “We yell, and they hear us through a speaker underneath,” Roberts says. “Like, ‘That looks good, move to your right!’”

What really sells the ships\' ocean journeys are blue-screen and green-screen visual effects, inserted later. The below-deck scenes of the

are shot on a separate soundstage, where you can walk through the cabins and holds, or even sleep in the tour bus-like bunks. The windows look out to a “horizon,” which comes later. Shooting above deck, however, requires the cooperation of the weather. The ships can be moved around to get the best angle, so that, for example, the director of photography can shoot with the sun as a backlight. “We had to wait and wait and wait to get some cloudy skies for one scene,” Roberts says. “It was too clear.... And then we had one great stormy day, and I was lucky enough to have three cameras up, and we had four or five actual lightning strikes.”

Claire has a lot of work ahead of her. Watch a new #Outlander at 8PM E/P or NOW on the @STARZ App. #HeavenAndEarth https://t.co/GEqYWkh3e3 pic.twitter.com/TvbDfSkjwi

If you\'ve been impressed with the actors\' ability to make it look like they\'re staggering about on a wave-borne vessel, there\'s actually a secret to that. Both the below-deck and above-deck spaces on the

are mounted on a gimbal with hydraulics underneath, giving the rolling impression of being at sea. “It’s hard to fake that,” Roberts says, as we try to steady our sea legs, the floor moving beneath us. Surface water and crashing waves are simulated, but the water rushing on to the deck is all real, lashed about by a combination of wind and rain machines. “What I enjoyed most was that we’d rehearse it when the actors are dry, and then they have to get wet,” Roberts says. “So my favorite part of the day was when I could just completely soak them. I know they secretly loved it.”

We’re #thankful for stolen moments below decks. #Outlander pic.twitter.com/Ix7tkZPZnn

The waves might be fake, but Heughan learned that they can feel pretty real. To pull off one stunt where a wave was supposed to hit him and toss him to the other side of the boat, he tried to fall on soft bags, “only to discover that they weren’t soft at all!” the actor laughs. “But I’ve had a lot of fun on the boats, especially with the rigging, climbing to the top.”

Doing all the season’s sailing on this parking lot sea saved

“vast amounts of money,” Roberts says. Had the production remained in Scotland, they could have only spent about half of one episode at sea, versus the several episodes we actually saw in the end. “All of the other episodes would suffer,” Roberts says. “We wouldn’t have been able to tell the story.”

What It\'s Like to Film an Outlander Kissing Scene

Cesar Domboy and Lauren Lyle Talk Outlander

Outlander: Jamie Loves Grey Hair, Is Perfect

Outlander: Jamie and Claire Made a Huge Mistake

Watch Jamie\'s Most Romantic Outlander Moment Yet

What the Cast of Outlander Looks Like in Real Life