The first set of foundations for Deepwater Wind’s offshore wind farm near Block Island was loaded onto a barge in Louisiana over the weekend and will begin its slow journey across the Gulf of Mexico and up the East Coast later this week.

Since late last year at its work yards in Houma, La., Gulf Island Fabrication, a company that specializes in marine structures, has been building the five foundations for the Block Island project, which is set to go online next year as the first offshore wind farm in the nation.

Because no other offshore wind farms have been built in the United States, Providence-based Deepwater turned to the offshore oil and gas industry for marine engineering and construction expertise. The foundations for the five-turbine wind farm were designed by Keystone Engineering, a Louisiana firm, and built by Gulf Island, a Houston company that has worked on some of the largest oil platforms in the world.

Each steel latticework foundation for the Block Island Wind Farm has been assembled in two main sections: the jacket, which measures 110 feet tall and will be secured to the ocean floor with piles, and the deck, which stands 60 feet tall and will sit on top of the jacket. A wind turbine will be bolted onto a cylinder in the center of the deck.

Gulf Island is still finishing the work for Deepwater. Completed foundations are moved on to barges so they can be shipped out. Each barge will travel alone, not in a caravan.

The first “loadout” — the process of moving foundation sections from land onto a cargo barge — started Friday and wrapped up on Sunday without a hitch, according to a spokeswoman for Deepwater Wind.

The sections didn’t have far to go because Gulf Island’s yards straddle the Houma Navigation Channel, a man-made canal that cuts through the Louisiana bayou and connects to the Gulf of Mexico. The first barge, which is docked in the channel, is carrying two jacket sections, one deck section and several piles.

When it leaves Gulf Island’s facility sometime in the next few days, it will travel about 30 miles south to the Gulf, continue southeast, round Florida and turn north toward Block Island, a journey of about 1,800 miles that should take 15 days.

While it’s en route, an installation barge with a crane operated by Weeks Marine, of New Jersey, will arrive at the project site, about three miles southeast of Block Island, to start preparations for the start of offshore construction.

The cargo barge carrying the foundation sections should arrive in mid-July. Additional installation vessels, tug boats and crew vessels from Rhode Island, Massachusetts, New York and Louisiana will also make their way to the site of the wind farm as construction starts.

Loadout of the second barge is scheduled for next week. A third — and final — barge will follow.

It is expected to take eight weeks to install all five foundations. The towers for the wind turbines will arrive in Rhode Island for assembly this fall, but they won’t be fitted on top of the foundations until next year.