On November 20, 1999, at 1931 hours Hawaiian standard time, a Piper PA-28-181, N4148X, performed an emergency ditching approximately 305 miles northeast of Hilo, Hawaii. The ditching was precipitated by a loss of oil pressure and the subsequent seizure of the engine. The pilot and his passenger suffered minor injuries related to exposure from time spent in the ocean following the ditching. The airplane sank and is presumed to be destroyed. The airplane was operated under the provisions of 14 CFR Part 91 by J. K. Viking, Inc., of Mission, Kansas. The purpose of the flight was to ferry the airplane from Santa Barbara, California, to Hilo, and eventually to Sydney, Australia, for resale. The airplane departed from Santa Barbara at 0630 Pacific Standard Time. According to the New Piper Aircraft Company, the airplane was manufactured on September 28, 1999. The Federal Aviation Administration's Long Beach, California, Flight Standards District Office had issued a special airworthiness (ferry) certificate for the airplane on November 15, 1999. The airplane had been modified with a special 110-gallon synthetic fuel bladder located behind the pilot's seat. The fuel bladder was connected with a 250-psi fuel hose to an electric/manual fuel pump. The pilot said that the oil system on the airplane had not been modified. The pilot stated that the flight was normal after they departed Santa Barbara. When they were approximately 600 nautical miles from Hilo, they noticed a gradual loss of oil pressure, accompanied by an increasing oil temperature. They called the U.S. Coast Guard and requested assistance. A Coast Guard C-130 was launched from Oahu to locate the airplane and provide an escort towards Hilo. The Coast Guard airplane rendezvoused with them about 400 miles from Hilo. The pilot stated the engine seized completely after all oil pressure was lost when they were approximately 340 miles from Hilo. The seizure was preceded by a knocking sound coming from the engine. The Coast Guard reportedly laid a flair path for the airplane as it prepared to ditch at sea in dark night lighting conditions. A merchant ship picked up the pilot and passenger about 0450 local time and transported them to Hilo. The pilot was located and interviewed after he was rescued. He told investigators that he was ferrying the airplane to Hilo with another pilot who holds an Australian pilot's certificate. He stated that he considered the other pilot a "co-pilot" because at his age, he liked to have a second pilot along. A review of the FAA Form 337 indicates that the ferry weight and balance computation for the ferry flight documented that the co-pilot's seat, and both rear passenger seats, had been subtracted from the basic empty weight. The pilot told investigators that the passenger sat in the No. 2 seat, which he had reinstalled in the aircraft. He stated that he did not have the Form 337 corrected to show that he had reinstalled the No. 2 seat. The pilot stated that the airplane had undergone a 50-hour inspection, and that it had about 35-38 hours total time on it when it sank. The pilot did not return the Pilot/Operator Report after numerous attempts by the investigator to gather this information.