Jindo, South Korea (CNN) -- Divers searching the wreck of the sunken South Korean ferry are finding cabins overfilled with people, but they are encountering major obstacles in recovering bodies, South Korean officials said Friday.
Searchers discovered the bodies of 48 girls wearing life vests in a cabin with a capacity of 30, indicating many passengers ran into the same room when the ship tilted.
The ferry Sewol is on the sea floor and resting with its right side up, said Capt. Kim Jin-hwang, a South Korean navy officer commanding the rescue operation.
Searchers are now trying to reach a dormitory-style cabin where they believe as many as 50 girls may be, he said.
Officials said conditions remained challenging inside the submerged vessel.
The visibility is very poor and lots of floating objects are blocking the way, the officials said. Some doors can't be opened because of the water pressure, and divers are having to break windows to gain access to certain parts of the ship.
Most of the bodies being found are wearing life vests, which probably made it harder for them to escape when the ship tilted because the exits would have been underwater below them. Divers have had to take life vests off the bodies to carry them out, Kim said.
Meanwhile, strong currents are pulling hoses supplying air to the divers, making it hard for them to stay underwater for long.
The divers have already searched all the easily accessible places, Kim said. They are expecting the search to become harder because of strengthening currents and harsher weather conditions.
Safety concerns about sister ship
A sister ship of the sunken ferry operated by the same company was found to have multiple safety concerns, investigators told CNN.
The prosecutor's office leading the investigation in the southern city of Mokpo said that authorities have been looking at the passenger ferry Ohamana, a ship owned by Chonghaejin Marine. That company also owns the Sewol, which sank off the country's southwestern coast on April 16 with 476 people on board.
The Mokpo Joint Investigation Force Headquarters examined the Ohamana because of its similarities to the Sewol and to get an idea of how the Sewol may have been operating.
Investigators inspected the ship and took away documents from the ship's offices Friday. They studied the emergency escape plans and found the following issues:
• Of the life rafts on board, 40 did not work.
• The emergency slides did not work.
• There was no equipment to tie down cars.
• The equipment for tying down containers didn't work very well.
Like the Sewol, the Ohamana had been modified to add more passengers, the prosecutor's office said.
The Ohamana usually operates between Incheon and Jeju three times a week. According to the ship tracking website MarineTraffic.com, the Ohamana arrived in the port of Incheon on April 16, the day the Sewol sank, and has not left since.
The South Korean Ministry of Oceans and Fisheries said that the Ohamana ceased operating right after the sinking.
Families confront officials
The revelations about the sister ship came Friday, the day after angry relatives of missing ferry passengers cursed government and police officials for failing to do enough to save the lives of their loved ones as hopes of finding survivors dimmed.
The relatives berated Fisheries Minister Lee Ju-young and two coast guard officials, accusing them of misleading the public about the operation and of wasting time.
"How can you fool us into believing you were out there trying to save our children?" one mother yelled at the officials.
Also, officials at the South Korean headquarters for the task force coordinating the search told CNN that they believe the body of a boy who reportedly made the first emergency call from the ship after it began to list sharply has been recovered. DNA tests will help officially identify the remains, officials said early Friday.
Investigators urge patience
On Friday, an official involved in the investigation in Mokpo asked for patience.
"I know a lot of people are curious as to the cause of the accident, but we don't have the information yet," said Heo Yong-beom, a maritime safety judge. "We will try our best to satisfy and answer questions."
The ferry Sewol lurched on its side and capsized last week. Among the passengers were 325 high school students on a field trip to the resort island of Jeju.
The number of confirmed dead rose to 185 on Friday, with 117 still missing, according to the South Korean coast guard.
Hopes of finding any survivors in the sunken ferry have all but evaporated after news that divers have found no air pockets on the third and fourth levels of the ship, where many passengers were thought to have been trapped.
Rescuers saved 174 people on the day the ferry sank, including 75 high school students, but no survivors have been found since.
Authorities do not yet know what caused the sinking, but a widening criminal investigation has ensnared the ship's captain and more than a dozen other crew members and led prosecutors to search the offices of the company that owns the ship.
Officials also searched the offices of 20 affiliated companies and the home of Yoo Byung-un, the man whose family is believed to be behind the company, looking for any evidence of wrongdoing that could have led to the ship's sinking.
Among other things, investigators have said they will look into whether modifications to the ship in 2013 could have altered the ship's balance and contributed to what happened.
Kim Yong-rok, an opposition lawmaker who represents Jindo, an island near where the ship sank, told CNN that modifications to add 117 more passenger cabins to the ship raised the ferry's center of gravity.
Kim said the work on the ferry took place in 2013 after the Sewol was purchased from a Japanese company. The ferry's passenger capacity was expanded from 804 to 921, he said.
South Korean prosecutors were unable to confirm those details for CNN.
But they are investigating the private organization responsible for inspecting and certifying ships for the South Korean government, which signed off on the work.
Authorities said it didn't appear that the ferry was overloaded, according to figures provided by the company and the South Korean coast guard. But coast guard officials said investigators won't know for sure how much cargo the ship was carrying until it is raised from the waters of the Yellow Sea.
U.S. President Barack Obama offered America's sympathies to South Korea on Friday during a diplomatic visit there.
He presented South Korean President Park Geun-hye with a framed American flag that was flown over the White House the same day the ferry sank as a symbol of condolence.
"I'm very mindful that my visit comes at a time of mourning for the people of this nation," he told the U.S. and the South Korean delegations.
"As allies but also friends, we join you in mourning the missing, and especially the young people."
"President Park, I thought it would be appropriate and fitting today to honor the dead and missing if our delegation held a moment of silence," he said.
The two delegations then bowed their heads.
Speaking through a translator, Park thanked him for the gesture, and said, "The Korean people draw great strength from your kindness."
Click here for more from CNN.