The 40-year-old cargo ship never made it to Puerto Rico after it left Jacksonville, Florida, last week, and appears to have sunk near islands in the Bahamas.
The ex-crew members, who each last traveled on the ship at some point this year, said the ship had issues with taking on water.
"The chief cook's room was constantly leaking water," Kurt Bruer, a quartermaster who spent six months on El Faro, said. There were other problems. "The drainage didn't work well on the ship."
The company that operated the ship, Totes Maritime, said in an email to CNN that the ship met all standards and certifications regardless of its age.
"The El Faro was a well-maintained vessel, classed by the American Bureau of Shipping and regularly inspected by that classification society and the (U.S. Coast Guard)," Tote said.
But Bruer and the other ex-crew members said the ship was showing its age.
Chris Cash, whose last voyage on El Faro ended in January, said it was time to send the ship to the scrapyard.
"The El Faro was on its ... needed a death certificate. It was a rust bucket," Cash said. "You don't take a ship like that ... that ship wasn't supposed to be on the water."
He said the company seemed interested in maintaining the ship but doing so at minimal cost.
"They were bandaging the ship with extra steel all the time," Cash said. "It seemed like they didn't want to put any money into the ship. When things would break they would just patch it up rather than really fix it."
Marvin Hearman, on the ship when it returned to Jacksonville in late August, said there was rust everywhere on El Faro and compared it to a 40-year-old car. He also said the cook's room leaked a lot of water. Bruer said the ship had holes in its deck.
While everything on the ship was old, everyone felt safe, Hearman said.
Still, he and the others were stunned the ship left while there was a big storm in its potential path.
Cash said: "I was very surprised when I heard about the ship leaving during a storm, but when I saw (the captain's) picture it all made sense."
Cash thought Capt. Michael Davidson was stubborn and cocky, but the other two disagreed that Davidson was to blame.
Bruer, who was terminated by Davidson for a reason he wouldn't disclose, said Tote was at fault for the old ship being permitted to set sail into stormy seas. Hearman said he thought Davidson likely was trying to prove a point to the company that he could do the job.
"He was a good captain," Hearman said.
The shipping company said it trusted Davidson to make the right decision.
"Tote Maritime has great confidence in its highly experienced officers," the company said. It added that it wouldn't comment on the ex-crew members' comments about the ship and the captain.
Captain's plan: Avoid the storm
Tote has said Davidson had a "sound plan" to avoid Hurricane Joaquin, a strategy that only unraveled when the ship's main propulsion stopped working.
The captain had current weather information when he left the port in Jacksonville for the four-day voyage and reported favorable conditions at the outset, Tote Services President Phil Greene told reporters earlier this week.
Given the weather system, the captain's "plan was a sound plan that would have enabled him to clearly pass around the storm with a margin of comfort that was adequate in his professional opinion," Greene said.
A friend of the captain agrees with the assessment, describing Davidson as a capable and experienced mariner.
"My guess is that he saw that he could outrun the storm, providing everything went right," said Larry Legere, of Maine.
But the ship's main propulsion failed, the ship's owners say, stranding the 33 people aboard in the path of the storm, which had become a Category 4 hurricane.
Authorities have found one body and debris, but have not seen the ship nor any survivors since the cargo vessel lost contact near the Bahamas on Thursday, just as Hurricane Joaquin was churning through the area.
A U.S. Navy salvage unit will join the search for the wreckage of El Faro, a source close to the investigation said.
The National Transportation Safety Board requested the vessel head to the search site and survey the area to pinpoint the ship's location.
The hope is to mobilize the salvage unit by the end of the week, the source said.
Crews found two debris fields -- one about 345 square miles near El Faro's last-known location (36 miles to the northeast of Crooked Island in the Bahamas) and one 81 square miles located 69 miles north of that position.
The U.S. Coast Guard called off its nearly weeklong search for the missing crew of the container ship at sundown Wednesday.