I was the pilot of a single engine turboprop aircraft when we suffered a critical engine failure resulting in a Pacific ditching 1,000NM from land. The copilot and I were just past half way on our journey from California to Hawaii. Following the engine failure we had multiple failed attempts to restart the engine, and were hence forced to ditch the aircraft. I was so grateful to have my ACR PLB with me, as it was our saving grace. We ditched at approximately 1500HRS, and roughly 4 hours later a bulk carrier and USCG C130 were overhead. After many failed attempts to pick us up, the rescue was postponed for the night due to the rough sea conditions. The following day, 5 more rescue attempts were unsuccessful by the first bulk carrier. A second US cargo ship attempted a rescue, and was successful on first attempt. We had been rescued after 22 hours in the life raft.