It's springtime, which means it's also time for the annual migration of yachts from the Caribbean to the Mediterranean.
And for yacht owners who don't want to bother with the time and hassle of an ocean crossing, there's an alternative: shipping the yacht by boat.
A growing number of companies are offering "yacht shipping" services, where yachts are loaded and carried on giant cargo ships to distant locations. Most of the boats being carried are charter boats on the seasonal migrations between the Caribbean and the Mediterranean.
Yet yacht-shuttles are also carrying boats to the South Pacific, and remote parts of Asia and Latin America. The services allow boat owners to fly in, use their boats and then have them transported to their next location. Industry executives estimate that more than 4,000 yachts will be transported by boat this year.
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"For a lot of owners, time is of the essence," said Catalina Bujor, spokesperson for Dockwise Yacht Transport, the largest of the yacht transporters. Dockwise also runs a "yacht shuttle" between Newport, Rhode Island and St. Thomas.
Yacht transporters say that in addition to saving time, yacht-shipping allows owners to avoid the wear and tear that can come with an ocean voyage. After long ocean trips, boats can often require re-painting and repairs. Most yacht-shippers allow one passenger—sometimes the yacht captain—to accompany their boats on the voyage.
Dockwise recently introduced its latest yacht-carrying mega-ship, called Yacht Express. It can carry more than a dozen boats, depending on their size. The largest yacht Dockwise has shipped was over 200-feet long. But many of the boats it carries are smaller sailboats, sport-fishing boats and leisure cruisers.
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The Yacht Express and other yacht-carriers are semi-submersible, which means the ship's cargo bay fills with water to allow the boats to pull into the ship. Once they're loaded and fastened, the water is drained for the ocean voyage. The process is reversed when the ships get to their destination.
Shipping a yacht isn't cheap. The cost of shipping a 120-foot yacht would be about $175,000, according to Dockwise.
Dockwise shipped about 600 boats last year and expects similar numbers this year. The yacht industry is still struggling from an over-supply of yachts for sale and charter, with prices still down 30 percent or more from the pre-crisis peak.
Yet for yacht-shippers, demand continues to slowly rebound.
"We've managed to do well despite the economy," Bujor said.
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How the Yacht Express Works:
First, the vessel submerges to allow the yachts to sail in the dock bay without hitting the deck.
All aboard! The yachts are in, but there is still plenty to do to prep for delivery.
The yachts' engines are switched off and divers enter the water to determine the clearances for each vessel. This helps determine where rubber mats and wooden cribbing blocks are placed. Divers also put the prepared temporary supports in place.
Later the deck will be drained and supports are fastened in place by welders.
A deck's eye view of the yachts with their sea fastenings in place.
Boats secured, the cargo ship heads to its destination.
-By CNBC's Robert Frank. Follow him on Twitter