SEA CHEST INSPECTION SYSTEM DEVELOPMENT AND QUALIFICATION AN IMPROVED SOLUTION FOR EXAMINATION OF NAVY SHIPS WASTER SLEEVES WITH THICKNESS MEASUREMENT AND PHOTO MAPPING

摘要

Gathering information on the condition of sea chest waster sleeves in Navy vessels and aircraft carriers represents a challenge. The waster sleeve's lack of accessibility from the outside piping and the limited access from the inside sea chest cavity make inspections a complicated task. In order to inspect sea chests cavities from the top, inboard divers must blank off the bottom opening of the pipe and remove the ship's force valve. This is a time consuming and difficult process. To save time, visual inspections are now being performed from under the ship's hull with a small camera introduced in the inside of the sea chest. These inspections often rely on a diver's ability to move a video camera throughout the length of the sea chest pipe and to capture as much useful video imagery as possible. Unfortunately, this method is not practical, as it provides qualitative but not quantitative data. In most cases not just video but thickness and corrosion data are necessary to make an accurate maintenance decision. This paper introduces a tool that can provide quantitative results: the Sea Chest Inspection System (SCIS). SCIS represents a new generation of high resolution; high speed remotely operated ultrasonic corrosion and thickness mapping systems capable of recording images, videos, and thickness measurements simultaneously. This system was developed under the leadership of the Naval Sea Systems Command - Office of Director of Ocean Engineering, Supervisor of Salvage and Diving (NAVSEA 00C) and is in the stage of testing and NDT certification. The SCIS is diver deployed and remotely operated. C scan image and video and still images are recorded to produce X-Y representations of the sea chest waster sleeve through a thickness color coded map and photo mosaicing of the entire internal surface. The coordinate references of these maps correlate with each other making it easy to review areas of interest and to assist in ship maintenance decision making.