Offshore Petroleum Discharge System

ABSTRACT In response to the needs of the operation forces to be resupplied with petroleum products, over the beach, the Offshore Petroleum Discharge System (OPDS) has been designed, the prototype OPDS demonstrated, and procurement actions initiated for additional systems. This paper describes the OPDS program. INTRODUCTION In October 1985, the Navy completed the demonstration of the newly developed prototype Offshore Petroleum Discharge System COPDS). This system is capable of delivering 1.2 million gallons of petroleum products per day to the beach from a tanker moored four miles offshore. Based upon this successful demonstration, the decision has been made to add additional OPDS to the strategic sealift inventory. OPDS is a welcome and much needed troop support capability. We can appreciate just how needed OPDS is when we recognize the fact that the Marine Amphibious Brigade, with all of its tanks, assault amphibians, aircraft and support vehicles, will run out of gas soon after landing if not resupplied. Prior to OPDS there were no systems with the capability of OPDS. The existing, less capable POL resupply systems took too long to install and were not dependable in adverse weather conditions. Of course, the best way to resupply forces ashore is to bring your tankers into terminals and have them discharge directly into tank farms or inland POL distribution systems. However, it is easy to think up scenarios where the terminals are too far from the scene of the action to be useful, or where terminals in the area have been blocked or damaged beyond immediate use. The solution to these problems is OPDS. But just what is an OPDS, and how does it work? OPDS PROTOTYPE SYSTEM DESCRIPTION The OPDS, as exemplified by the equipment used in the 1985 demonstration, is made up of three subsystems; the OPDS tanker, the flexible pipeline, and the single anchor leg mooring or SALM. TANKER SUBSYSTEM: For the demonstration, the OPDS tanker was the modified T-5 SS POTOMAC. The POTOMAC has a length of 620 feet, beam 83 feet, draft 33 feet, and displacement of 34,800 long tons. The tanker was modified to be able to carry and deploy the four miles of flexible pipeline and the SALM. The modified POTOMAC is shown in figure (1). Forward are the eight pipeline reels. Each reel is hydraulically operated, and contains one half mile of pipeline. The POTOMAC has been fitted with all of the deck handling equipment needed to couple hose sections together and guide them overboard. The other major modification to the POTOMAC was installation of the SALM skid beams. These beams, shown in figure (2), allow the POTOMAC to selfload and offload the SALM. When loading or offloading, the tanker is listed 13 degrees to port and the beams are extended so that their ends are under water. In this position the beams can hook onto, or release the SALM.