A passenger says a collision Silversea Cruises called \"minor\" put a hole in a cruise ship and badly damaged a Vietnamese container vessel. Andrew Lock told CNN Monday he and his wife were on board the Silver Shadow when it hit the other vessel off the coast of Vietnam in a heavy fog Friday. He said the two ships were about 5 miles off shore. The couple looked up when they heard the foghorn at the front of the Silver Shadow sounding loudly and saw the container ship, he said. They just had time to brace themselves before impact. \"The Vietnamese ship rolled over -- at a 90-degree angle. In fact, we thought it was going to capsize. It then righted itself,\" he said. \"And with the forward momentum of our ship, it pushed the Vietnamese ship around, so that it actually came down the side, the length of our ship, scraping along the side as it went. And from that viewpoint, we could see just how much damage had been done to that ship, and it was substantial.\" Lock said there were no injuries he knew of on the Silver Shadow but he saw crew members on the other vessel lying on the deck. When the Silver Shadow docked in a port the next day, after anchoring for the night in Ha Long Bay as planned, he and other passengers saw a hole in the bow. Silversea, based in Monaco, released a statement saying the Silver Shadow, which is registered in the Bahamas, was involved in a \"minor incident.\" It said it would investigate.