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7 NAVAL OPERATIONS INTRODUCTION The Department of Defense (DOD) is concerned that a proliferation of offshore platforms left in the marine environment after their useful life will adversely affect national security by constraining offensive and defensive naval operations. To fulfill its mission, the Navy must have the freedom to utilize the seas, both surface and subsurface. Safety of navigation is of critical concern. From a defensive perspective, the Navy must also be concerned with detection of unfriendly forces off U.S. coasts. Offshore installations compli- cate that mission because of their acoustical saturation of the water column and the restrictions they inherently place on the mobility of U.S. seaborne forces. The DOD has conveyed its concern and position to the oil and gas industry by producing a draft "Minimum Standards for the Removal of Offshore Structures and Installations" (see Appen- dix C). These draft standards are intended to influence industry practice, domestic regulation, and the development of international guidelines within the International Maritime Organization (IMO). Since the DOD has no direct decision-making role in any of these fore, as a practical matter the draft DOD standards set forth a negotiating position. The committee assessed the DOD position itself, considered its operational implications (if implemented), and also considered the international implications of the position. THE WD DOT ST - DARDS The DOD draft standards have been promulgated for interagency and industry consideration and are intended for ultimate submittal to the IMO. The most significant platform removal provisions of the standards are: a. All fixed structures utilized in the Exclusive Economic Zone or on the continental shelf shall, as an essential component of their design, provide for their effective and expeditious removal. 61

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62 This design provision is intended to impact mainly on the new generation of platforms which have increased dramatically in size as i ndus try has moved f urther of f shore i nto deeper and of ten rougher water. Platform des ign has therefore evolved over the years to the extent that the removal process has received increasing visibility. Small platforms in relatively shallow water, which can be lifted i ntac t, do not demand un i que des i En charac ter i s t i c s to permi t removal . b. It shall be the obligation of the coastal state to require that the corporate ent i ty, i ndividual or government under whose control the structure existed, ensure that it is removed and di sposed of when no longer used for hydrocarbon recovery . This provision is consistent with existing international law in that the nation that exercises resource jurisdiction in the area of the platform bears the ultimate responsibility for ensuring compliance with international removal standards. However, it would appear that this is a strict interpretation of the law, which could run counter to developing international practice (see Chapter 4). c. In order to maintain an environment suitable for all forms of navigation and other uses of the sea, removal shall be to within 5 meters above the seafloor in waters less than 400 meters, to within 15 meters above the seafloor in waters less than 2, 000 meters and greater than 400 meters . This apparent relaxation of removal standards may not be that. Current law and practice results in removal of structures approxi- mately 5 meters below the mudline. Cutting at 5 meters above the seafloor, (or 3, 20, or 40 meters) may be more difficult and dangerous . (The proposed DOD standards would of course permit continued cutting below the mudline if that option is preferred.) In deeper water, toppling of platforms has been considered an alterna- tive. It is unlikely that platforms currently on the disposal list would meet the DOD 15-meter limit fen the toppled condition unless additional portions of the jacket were collapsed or removed. If industry were to come forward with reasonable alternative depth removal figures that would still protect U.S. submerged mobility and security concerns, the DOD would be open to discussing them. d. All structures not entirely removed shall at a minimum be modified to the above height and depth standards, shall be indicated on marine charts prepared by the coastal state, and under guidelines provided by IMO, appropriate publicity shall be given regarding the depth, position, and dimensions of any installations or structures not entirely removed

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63 This requirement is similar to accepted practice for providing notice of wrecks and submerged obstructions. e. Nothing shall preclude any coastal state depositing concen- trations of removed structures in special areas for living resource sanctuaries or related purposes so long as such placement does not interfere with navigational and other nonfishing activities. This provision is in accord with the Law of the Sea Convention provisions concerning the rights and privileges of coastal states In the exclusive economic zone. f. Except in archipelagic sealanes and in international straits, nothing shall preclude the coastal state, in its territorial sea (up to a limit not exceeding 12 nautical miles) or in waters less than 20-meters in depth, from permitting exemptions from these provisions. This provision recognizes the increased discretion of the coastal state in its own territorial waters to adopt more lenient standards (except in international navigation routes, such as straits and archi- pelagic sealanes, where the interests of the international community continue to control). The 20-meter depth exemption, which pertains to the continental shelf, takes into account the fact that in such shallow areas certain forms of navigation are restricted in any event (e.g., unsafe for submarines submerged or for deep-draft vessels3, and thus, removal standards may be less stringent. IMPLICATIONS FOR SUBMERGED NAVIGATION The partial removal criteria under discussion essentially rule out collision between a surface ship and the platform residual material. There remains the operational concern of submarine collision. Platform bases may cover a few hundred feet on a side. They are comparable in size to another submarine, but when considered from a "density" viewpoint--that is, structure volume or area per square mile--the obstruction represents less than 1/2 of 1 percent of the area. A discussion of density, however, does little to assuage a submarine operator's safety and security concerns, even if low risk of collision does exist (see Chapter 6~. Accordingly, U.5. Navy Submarine Force practice prohibits submerged operations within ~ radius of S-nautical miles of fixed offshore platforms. This means that each platform reduces the area available for submarine operations by as much as 80 square miles, depending on the density of platforms. The most pract ical and widely used underwater detection system for avoiding collision is sonar. Platform residuals present an effective target to certain types of sonar and may not be visible to other types

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64 designed for totally different missions. The typical platform target is a collection of hollow pipes with considerable space between them. In addition, it is on the ocean floor, returns from which may effectively mask target echoes. Lastly, it is not a moving target, and thus presents no doppler distinguishing echoes. Pri no i pal active submar i ne sonars are designed for search and detection of other submarines and surface ships. They are relatively low frequency, low resolution (related to detectable object size), and long range. In brief, platform residuals and principal submarine sonars are not especially compatible. Irrespective of performance, submarines do not customarily use their principal sonars in an object avoidance or navigation obstruction role. Furthermore, other sonars designed for shorter range, smaller object detection are not routinely used. Any active sonar compromises the position of the submarine, contrary to its mission to run silent and avoid detection. However, should submarines chance to operate in areas where partially removed platforms exist, it is reasonable to expect they might use their fathometer to maintain sufficient altitude to remain clear of residuals. DISPOS ITION OPTIONS The DOD draft standards are not specific with respect to actual platform disposition except that they recognize the permitting of platforms as artificial reefs. Whatever the ultimate disposition of the structure, whether removed to shore, emplaced elsewhere, or ocean dumped, the DOD draft standards would apply. They would require that no residual material be left that is higher than 5 meters or 15 meters; that artificial reef permitting procedures be adhered to; and that ocean dumping must be in deeper depths than 2,000 meters if structure size is greater than 15 meters in any dimension. The DOD draft standards do not specifically address the options of toppling in place, but if the residual material meets the maximum permi ss ible heights off the bottom, and other constraints are met (e.g., charting) toppling would appear to be consistent with the draft s tandards . However, the large size of complex platforms, which would most likely be selected for toppling (as a cheaper removal alternative), makes it all but certain that addi t tonal di smemberment would be required either prior to the toppling or after the structure is lying on the seabed. This added demolition or cutting cost militates against toppling as the disposition choice. It appears, then, that the DOD draft standard and the disposition matrix are compatible only in the complete or partial removal categories, unless industry and DOD can agree on somewhat modified depth standards to allow for toppl ing .

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65 INTERNAT f ONAL IMPLICATIONS As discussed elsewhere in this report, removal standards are likely to be the subject of discussion at the Intergovernmental Mari time Organization in the relatively near future. Formulation of a U.S. position for presentation may perhaps take some time because of the complexity of this issue and the varied approaches being taken by responsible agencies and affected interests. The Department of Defense proposals on removal standards will be an important contribu- tion in the process of preparing for IMO negotiations. The United States will be well served by the achievement of ;nter- national agreement on standards that are acceptable to this country. In anticipation of difficulties in negotiations to accomplish that result, interagency coordination and discussions on removal standards should begin promptly, with the Department of Defense as an active participant.