Updated

A U.S. Navy warship is bringing hundreds of Marines and sailors, along with power generators, water purifiers and bulldozers, to bolster relief efforts in Haiti, where Hurricane Matthew has left at least 750,000 people desperately in need of assistance.

Navy Capt. James Midkiff, commander of the USS Iwo Jima, said the eight helicopters on the ship will start ferrying food and medical supplies for aid organizations upon arrival, which is expected as early as Wednesday. The Iwo Jima can also provide medical help in Haiti, where hundreds have died, the injured languish unattended in hospitals, doctors warn of a surge in cholera and anger is rising in remote communities still awaiting aid a week after the hurricane struck.

The Iwo Jima is carrying more than 1,100 sailors and 600 Marines, and with them the number of U.S. military personnel in Haiti to provide relieve will rise to about 2,500.

While the Marines and sailors have yet to be given their marching orders about what they will be doing, the plan is to "alleviate some of the suffering that is going on and prevent any additional loss of life," said Lt. Col. Christopher Hafer, the commanding officer of the Marines' Combat Logistics Battalion 24.

Matthew has officially left 473 people dead as of Tuesday, according to the National Civil Protection headquarters in Port-au-Prince. But local officials in one southwestern region, Grand-Anse, said the death toll there alone tops 500.

The U.N. humanitarian agency in Geneva has made an emergency appeal for nearly $120 million in aid, saying that about three-quarters of a million people in southwest Haiti alone will need "life-saving assistance and protection" in the next three months.

Speaking from his cabin aboard the ship, Midkiff said the Iwo Jima dodged Hurricane Matthew twice and Tropical Storm Nicole as it collected Marines and supplies and headed for Haiti. The ship left its home port in Mayport, Florida, as the base was being evacuated ahead of Matthew.

"It sounds like I'm making some of this stuff up," he said.

Tthe Navy then directed the Iwo Jima to Norfolk, Virginia, to pick up some Marines and head for Haiti.

Along the way it encountered the outer bands of Matthew and then the swells from Nicole, which later strengthened into a hurricane. It also collected some Osprey aircraft and more Marines from the USS George Washington, an aircraft carrier whose orders to help out in the storm-hit Bahamas were cancelled. The Iwo Jima will relieve the USS Mesa Verde, another U.S. ship that has been helping in Haiti but needs to prepare for a future deployment.

Standing in one of the hallways of the Iwo Jima, Matthew Estes, a 31-year-old Navy medic from Corryton, Tennessee, said he's excited to help Haitian civilians who are "devastated down there."

"Before I left, I was nervous, anxious and overwhelmed with excitement," he said. "I'm doing the job that I want to do — that I joined to do."

He was an emergency medical technician in Tennessee as well as a landscaper before joining up.

"My wife was a little upset, but she understands the pick-up-and-go," he said. "She cried a little on the phone but then texted me and said this is what you joined to do, what you love to do."

Marine Lance Cpl. Zachary Younts, 20, of Dallastown, Pennsylvania, said he usually works on trucks as a diesel mechanic.

"I hate sitting in a bay working on an engine all day," he said. "I love this. This is awesome. It gives me a sense of doing something in my career."

Younts said he's excited to hand out food to civilians or ship out equipment, whatever is asked of him. He didn't know he was going to Haiti when he boarded a bus on Friday night from Camp Lejeune in North Carolina.

"I just knew I was going somewhere," he said.

Marine Lance Cpl. Shawn Durrell, 20, of Compton, California, said he expects to work hard.

"It's one of the biggest experiences of my life," he said. "Not only are we going to a different country, we're seeing what we can do. And we're here to help. One of the biggest things in life is to help."