Operation Dominic, Shot Sword Fish Scientific Director's Summary Report (1/21/63) (Deleted)

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D estroy this report when it is no longer needed. Do not return PLEASE NOTIFY THE DEFENSE NUCLEAR AGENCY, ATTN: STTI, WASHINGTON, DC 20305-1000, IF YOUR ADDRESS IS INCORRECT, IF YOU WISH IT DELETED FROM THE DISTRIBUTION LIST, OR IF THE ADDRESSEE IS NO LONGER EMPLOYED BY YOUR ORGANIZATION. .rIIBEST AVAILABLE COPYBEST AVAILABLE COPY

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REPORT DOCUMENTATION PAGE Approved for public rel ease; distribution 2b. DECL.ASSIFICA TION I DOWNGRADING SCHEDULE unlimited. 4. PERFORMING ORGANIZATION REPORT NUMBER(S) 5. MONITORING ORGANIZATION REPORT NUMBER(S) (If applicable) Defense Atomic Support Agency David Taylor Model Basfn Ba. NAME OF FUNDING i SPONSORING Bb. OFFICE SYMBOL 9. PROCUREMENT INSTRUMENT IDENTIFICATION NUMBER Be. ADDRESS (City, Stat11, and ZIP Code) 10. SOURCE OF FUNDING NUMBERS ELEMENT NO. NO NO. ACCESSiON NO. OPERATION DOMINIC, SHOT SWORD FISH, SCIENTIFIC DIRECTOR'S SUMMARY REPORT, Extracted Version W.W. Murray, Scientific Director FROM TO 114 DATE OF REPORT ('r"Hr,Month,Oay) rs PAG; COUNT 1s. SUPPLEMENTARY NOTATION This report has had sensitive military information removed in order to provide an unclassified version for unlimited distribution. The work was performed by the 17 COSATI CODES 18. SUBJECT TERMS (Continue on ,.verse if ntcesury and identify by block number) 18 3 Sword Fish Depth of Burst 19 7 Underwater Explosions Oceanography 19. ABSTRACT (Continue on reverse if necessary and identify by block number) Sword Fish was an underwater weapon-effects test and was the first occasion in which the Navy's Antisubmarine Rocket (ASROC) weapon system was used to deliver a nuclear depth charge. This report describes the overall test effort, provides general infonnat1on on conditions prevailing at the test site near burst time, and sunnarizes the project results as understood within a few weeks of test completion. - The primary significance of Sword Fish, from the viewpoint of a ship delivering an ASROC nuclear depth charge is to provide information bearing on: (1) mechanical damage to the ship (caused by underwater shock waves); (2) personnel injuries (caused primarilf by gamma-ray sources carried fn the base surge); and (3) restrictions on ship maneuvers due to contaminated water and sonar masking). 20. DISTRIBUTION/ AVAILABILITY OF ABSTRACT 221. NAME OF RESPONSIBLE INDIVIDUAL 21. ABSTRACT SECURITY Cl.ASSIFICA TION DD FORM 1473, 84 MAR 83 APR ed1t1on may be uHd until unausted. SECURITY CLASSIFICATION OF THIS PAGE AU other editions are obsolete. ·UNCLASSIFIEDBEST AVAILABLE COPYBEST AVAILABLE COPY

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SHOT SWORD FISH SCIENTIFIC DIRECTOR'S SUMMARY REPORT W.W. Murray, Scientific Director David Taylor Model Basin Washington 7, D. C.BEST AVAILABLE COPYBEST AVAILABLE COPY

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sword Fish weapon etfects objectives may be divided into two groups: those connected with onsite efforts and those connected with offsi te efforts. The term "onsi te" refers to ectivities conducted withi� a radius of 12 miles of su�face zero on test day. The short term objective of onsite efforts was to secure weapon-effects information bearing on the establishment of a tactical doctrine for nuclear warhead delivery. Specifically, this information will help to: (1) determine the minimum delivery range at which an ASROC destroyer (DD) can make an attack and retain its capability of mounting an immediate re attack (from the viewpoint of both equipment and personnel); (2) determine the minimum emergency delivery range at which an ASROC DD can make an attack and retain its mobility with possible weapon syste� equipment failures and personnel casualties; and (3) determine the restriction which an ASROC attack places on the later tactical maneuvers of a ship because of radiation hazards or deterioration of sonar conditions. The long term objective of onsite efforts was to enhance the general fund of information on effects on nuclear under water explosions. Specifically, this information will he:p to: 3BEST AVAILABLE COPYBEST AVAILABLE COPY

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(4) determine safe standoffs for delivery of underwater nuclear weapons by submarines; (5) establish reliable procedures for extrapolating to underwater nuclear bursts the statistically significant data on ship equipment damage gained from routine HE shock trials of operational ships. Objectives of the offsite efforts were concerned with: (1) the effects of the burst upon strategic hydroacoustic detection systems (e.g., SOSUS) and the improvement of long range hydroacoustic theory; (2) the long-time drift and diffusion of radioactive contaminants left in the water after the burst and the effect of these contaminants on marine life; and (3) the detection and identification of underwater nuclear Planning guidelines for the test were dominated by the short-term onsite objectives. The distinguishing feature of Sword Fish, as compared to previous underwater nuclear tests, was to be the inclusion of Navy ships, equipped with operational modern weapons, at ranges close enough to the burst to have tactical significance. Three FRAM-1 destroyers, equipped with the ASROC system, were to participate. One of these destroyers, Agerholm, was to launch the weapon from a distance slightly in excess of the minimum firing range. A second, Anderson, was to serve as a s�andby firing ship. The third, Bausell, was to be placed in tow, unmanned with its main machinery shut down but with selected weapon 4BEST AVAILABLE COPYBEST AVAILABLE COPY

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the damaged items were individually insignificant they resulted in considerable impairments of the ASROC system, antiaircraft capability, and conventional ASW capability. Damage was repaired on shipboard prior to the nuclear test. A wide statistical variation in damage to apparently identical ships under identical attacks was demonstrated. Two OperaticnalSuitability Test (OST) weapons were fired at a range of 4,000 yards, one each from Agerholm and Anderson, as part of the rehearsals. Preliminary estimates of the burst depths are 650 and 675 feet. Missile delivery accuracy was checked in one or these firings: the surface zero position of the burst was about 240 yards beyond the target, roughly along the line of fire. USS Agerholm launched a nuclear depth charge at the target raft in a lonely spot in the Pacific Ocean about 365 miles west of San Diego, California shortly after 1301 (local time) 11 May �962. Test conditions prevailing at shot time were determined and are summarized below:BEST AVAILABLE COPYBEST AVAILABLE COPY

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Nearly all measurements attempted during the ASROC test were secured. Information is in hand, at this writing, in most areas: surface phenomena, underwater pressures, ship shock motions, ship damage, base surge radiation, contaminated water pool, onsite sonar. In other areas, marine life and offsite hydroacoustics, a considerable amount of data was secured,but additional study is necessary before an intelli gible picture of the results can be drawn. Highlights of the results in hand are summarized in Chapter 5 and, more briefly, The most prominent surface phenomena were: the spray dome, the plumes, base surge, and foam patch. The spray dome 7BEST AVAILABLE COPYBEST AVAILABLE COPY

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stretched over a radius of nearly 1,000 yards from surface zero and rose to a maximum height of about 750 feet in 6 seconds. Radial plumes of water broke tnrough the spray dome 7 seconds after burst and reached a maximum height of 2,100 feet in 16 seconds, at which time they covered a radius of 600 yards from surface zero. The base surge, formed as the plumes collapsed, reached a maximum upwind distance of 2,000 yards 110 seconds after burst; at this time it stretched 2,000 yards crosswind and 2,500 yards downwind and was still expanding in these directions. The base surge settled and drifted with the wind; it remained visible for about 10 minutes but lingered as an invisible aerosol up to at least 20 minutes. The foam patch became visible as the base surge dispersed. It attained a radius of about 2,000 yards abou� 20 minutes after burst and subsequently lost its visible aspects. Underwater pressure waves consisted of the direct shock wave and pressure waves reflected from the sea bottom. The direct shock wave was typical for an underwater burst and was refracted by the thermal gradient existing in the water. Consequently, its s:rength near the water surface diminished more rapidly with distance from the burst than it would have in isovelocity water. The bottom-reflected pressure wave had a complex history, undoubtedly due to multiple sea bottom layers. Moreover, it showed some asymmetry with respect to 8BEST AVAILABLE COPYBEST AVAILABLE COPY

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Shock motions were predominantly vertical in the key surface ships. In all cases except Bausell, the response to the bot-tom-reflected pressure wave was greater than that to the direct wave: in Bausell the responses were about equal. As usual for underwater nuclear bursts the peak vertical velocities measured at ship bulkheads were about equal to the peak bodily velocity. The peak bodily velocities of key ships were: In Bausell about 1 ft/sec after both the direct and reflected pressure waves, in both Agerholm and Anderson about 0.5 ft/sec after the reflected pressure wave. 9 Page 10 deleted.BEST AVAILABLE COPYBEST AVAILABLE COPY

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Gamma radiation measurements at stations within the base surge indicated intensities of many thousands of roentgens per hour. However, intensities fell off rapidly with distance from the edge of the base surge. Bausell, 2,200 yards upwind, was not enveloped by the base surge, which stretched along a radial line to the ship to within about 350 yards of the:fanta.11: a finger reaching out on the windward side of the ship to about 2,000 yards may have come closer. A recorder on the fantail of Bausell showed a maximum intensity of 44 r/hr and a total dose of about 2 r; at other locations on Bausell,recorders registered much lower values. Bausell was not contaminated, The water about surface zero was left radioactively contaminated after the collapse of the plumes. For at least 20 minutes,the boundary·of this radioactive area is defined by the visible foam pat:ch. 11BEST AVAILABLE COPYBEST AVAILABLE COPY

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Certain aspects of the onsite results were ex�lored with the aim of generalizing the results, to a limited extent> though not appreciably beyond Sword Fish conditions. Destroyers could have been located closer than 1,700 yards to the burst without sustaining any mobility impairment; however, complete impairment of weapon delivery capability would be anticipated. Destroyers proceeding at 20 knots, or more, could have been located as close as 1,600 yards upwind or crosswind, or 1,800 yards downwind, of the burst and maneuvered so as to remain at least 350 yards beyond the edge of the base surge. Such destroyers would not have been contaminated and their personnel would not have received radiation doses in excess of peacetime test limits. Comparison of the results with Shot Wahoo of Operation Hardtack indicates that the ship damage and radiation results will not be 12BEST AVAILABLE COPYBEST AVAILABLE COPY

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appreciably changed by variations in yield and burst depth within the limits natural to a properly functioning ASROC Sword Fish was executed successfully, in both its operational and technical aspects. The ASROC system demonstrated its capability to deliver a nuclear depth charge. Associated technical measurements of good quality were secured, nearly to the fullest extent planned. Weapon effects conclusions apply to ASROC burst condit�ons. These conditions are a slight generalization of the Sword Fish conditions and encompass small variation resulting from a properly functioning ASROC depth charge fuzing system. Specifically, ASROC test conditions apply to vields betweer. 13 Page 14 deleted.BEST AVAILABLE COPYBEST AVAILABLE COPY

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to radiation would be less than limits set for 4. For about an hour after an ASROC burst the contaminated water left about surface zero will pose a radiological hazard of significance even under the exigencies of a wartime situation. In Sword Fish, Sioux entered the pool about 20 minutes after the burst and had to withdraw hastily, though she suffered no serious 15BEST AVAILABLE COPYBEST AVAILABLE COPY

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3. Sword Fish re-emphasized the-role of the base surge as a carrier of radioactivity. A ship which maneuvers, following an ASROC burst, so as to remain at least 350 yards from the edge of the base surge will not subject its personnel to radiation doses in excess of peacetime test limits. In Sword Fish the base surge remained visible for as long as 10 minutes; it settled and dispersed within about 30 minutes. 16BEST AVAILABLE COPYBEST AVAILABLE COPY

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In Sword Fish, Sioux encountered an invisible aerosol at 20 minutes and personnel on the weather decks were contaminated, though decontamination was 17 Page 18 deleted.BEST AVAILABLE COPYBEST AVAILABLE COPY

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2. The contaminated water pool produced by an ASROC burst drifts with the current while it diffuses and decays radioactively. This pool can be tracked for weeks. In Sword Fish the pool was tracked for more than twenty days; twenty days after the burst its center had drifted about 50 miles south of surface zero and maximum surface radiation intensity measured 0.04 mr/hr. 3. Considerable information was acquired, for study, 19BEST AVAILABLE COPYBEST AVAILABLE COPY

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on the effects of the radioactive wastes on 4. Information on the long-range hydroacoustic signals produced by the burst was acquired from ship and shore stations. Analysis should enhance ability to detect and classify underwater nuclear explosions. Several observations were brought to light during the planning and execution of Sword Fish, which bear on the performance of the ASROC system. These observations led to the following conclusions. 20BEST AVAILABLE COPYBEST AVAILABLE COPY

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Some of the implications of the Sword Fish results for possible design changes in the ASROC system were explored. While any change in present ASROC design must result from a Navy policy decision, three conclusions were drawn which · are believed to bear on this question. l. Sword Fish results suggest that a minimum delivery range as small as 1,600 yards could be employed by a destroyer, if immediate re-attack capability is 2. A reduction in cresign burst depth is not desirable. Such a reduction will not increase safety to the delivery ships to a sure and significant degree under all operational conditions. Moreover, it appears that any appreciable reduction in design burst depth will lead to a serious degradation of 21BEST AVAILABLE COPYBEST AVAILABLE COPY

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submarine kill probabilities, especilly in view of probable uncertainties in actually achieveble 3. Any appreciable reduction in de�ivery range should be accompanied by detailed reliable weapon-effects information in a form which is readily usable by the fleet under all operational conditions. 22BEST AVAILABLE COPYBEST AVAILABLE COPY

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Sword Fish was an underwater weapon-effects test executed in the Pacific Ocean off the southwest coast of the United States in May 1962 as part of Operation Dominic. Sword Fish was conducted under the technical and operational cognizance of a JTF-8 Navy task group. This test was the first occasion in which the Navy's Antisubmarine Rocket (ASROC) weapon system was used to deliver a nuclear depth This report describes the overall test effort, provides general i�ormation on conditions prevailing at the test site near _,burst time, and summarizes the project results as understoQ4 within a few weeks of test completion. Details of the results have been published separately by the parti cipating projects. The present report provides a timely evaluatio_� of the significance of the test results. It is personal opinions of the author; limited time does not permit solicitation of comments from the many participating project office�s and their home agencies.::: It is not intended to replace the present report with a later updated version. Final results will be published separately by the …