MAYPORT, Fla. -

Fifty-four Chilean sailors who have made Jacksonville home the last three months headed out from Mayport Thursday afternoon.

The Chilean submarine Simpson was on a three-month deployment to Naval Station Mayport for the diesel electric submarine initiative, a partnership between the foreign Navy and the U.S.

The U.S. Navy doesn't have a submarine like the Chilean Simpson in the fleet.

The partnership is an excellent training opportunity for the U.S. sailors because diesel submarines are the most difficult to track.

The submarine is 59 meters in length and can go 11 knots on the surface and 22 knots when it's submerged.

The diesel submarine that belongs to the Chilean Navy is called the SS-21 Simpson. It was built in 1982 and it has eight torpedo tubes.

"This ship is very unique," said Lt. Commander Corey Barker, of Naval Station Mayport said. "This is a type 209 diesel electric submarine. We don't have these in our Navy, so we don't know how to find them, how to engage them, how to practice with them."

Most foreign navies have submarines like the Simpson, so for sailors in the United States to learn about it is rare.

"It's basically an opportunity for our naval forces to operate with the small, fast, very stealthy diesel submarines to get experience working with them," Barker said. "It's a great opportunity for both the United States Navy and for the Chilean Navy."

During the three-month deployment to Naval Station Mayport, the Simpson crew also trained with U.S. Navy ships and helicopters.

"This is an ongoing program, partnership we have with all of our partners in South America, Chilean Navy, Brazilian Navy, Peruvian Navy," Barker said. "As a matter of fact, the last submarine that was in Mayport as part of this program was a Brazilian submarine."

The diesel electric submarine initiative increases cooperation between the US and partner nations and strengthens capabilities with the maritime strategy.

"All of our submarines are nuclear powered, very large, different mission capabilities and different mission packages," Barker said. "It's just a different type of ship we don't have in the U.S. Navy that we get to train with."