Hong Kong ( CNN ) -- They stepped onto the evening ferries in Hong Kong 's crowded harbor to watch the sky light up with fireworks to celebrate China 's National Day . Instead , the night ended in chaos and tragedy . Two ferries collided Monday night , upending one of the vessels and sending passengers into the water . At least 38 people died . Rescuers picked up 123 survivors and are still searching for a countless number of others who are missing . Passengers on board the ferries said they had only moments to escape . `` First it was up to here and then here . The water rose so quickly , '' one woman , who declined to be named , told CNN affiliate i-Cable . `` We thought we were going to die for sure . '' The boat rolled violently before it partially sank . `` I opened the window and pushed a child out . I put a life jacket on him and pushed him out first , '' he told i-Cable . `` At the time , it was very chaotic . The boat was completely standing straight up in the water . It was chaotic . All the tables and chairs were everywhere . It was like a slide ; everything was sliding down . '' Read more : Survivors recount chaos , horror of ferry collision . Authorities are investigating what caused the crash , Hong Kong 's most lethal maritime accident in more than 40 years . Police have arrested seven crew members from the vessels on suspicion of endangering passengers . The collision involved a passenger ferry traveling from Hong Kong Island to Lamma Island and a vessel owned by the Hong Kong Electric Company , which was carrying company employees and their families to watch the scheduled fireworks display . Government officials said it occurred off Lamma 's coast about 8:20 p.m . Photos : Deadly Hong Kong ferry crash . `` I thought we 'd hit a rock or a lighthouse , '' said Chris Head , a teacher who was on the passenger ferry . He said the vessel went from what felt like full speed to `` an abrupt halt . '' Head said the force of the impact threw him out of his seat at the back of the ferry , which was not very full of people . As the damaged ferry began to move toward a pier in the small town of Yung Shue Wan on Lamma , Head said , he could see the other boat had started to sink into the water vertically , like the Titanic . `` It was very dark , '' he said . `` There were very few lights on board . '' According to the Hong Kong Fire Services Department , which led the rescue , the vessel began to sink quickly after the impact . It said low visibility and many obstacles on board made work difficult for rescuers . `` After 10 minutes out , a boat crashed into ours from the side at very high speed , '' one male survivor from the accident told the South China Morning Post , a local newspaper . `` The rear of the ferry started to sink . I suddenly found myself deep under the sea . I swam hard and tried to grab a life buoy . I do n't know where my two kids are . '' Residents on Lamma , a lightly populated island southwest of Hong Kong Island , reported being awakened in the middle of the night by the massive rescue operation going on offshore . Were you there ? Share your stories , images and videos . On Tuesday , the front of the stricken vessel was still sticking out of the water , tethered to a barge equipped with a crane just a few hundred meters from the coast of Lamma . Emergency services boats surrounded the scene , and divers conducted a search . Despite a hole torn in its bow , the passenger ferry was able to dock safely after the crash . Government officials have not confirmed whether passengers aboard that vessel were injured , but Head said nobody around him appeared to have been hurt . The narrow sea lanes leading into Hong Kong 's main deepwater harbor are some of the busiest in Asia , with giant commercial freighters , ocean liners , passenger ferries and private boats of all sizes sharing the waters . Hong Kong is home to more than 200 outlying Islands , including Lamma . Hong Kong Island is on the south side of Victoria harbor , with Kowloon forming its northern shore . North of Kowloon lie the New Territories , which stretch all the way to mainland China . Monday 's crash is Hong Kong 's most lethal maritime accident since 1971 , when 88 people died after the ferry Fat Shan capsized between Hong Kong and Macau amid a typhoon . CNN 's Paul Armstrong , Jethro Mullen , Judy Kwon , Pamela Boykoff and Mark Morgenstein contributed to this report .
A passenger ferry collided with a vessel in Hong Kong 's crowded harbor . The death toll has risen to 38 , Hong Kong authorities say . Authorities are searching for countless others who are missing . Police have arrested seven crew members on suspicion of negligence .