Arsenal| HistoryNet

Arsenal | USS Grayback: Secret Submarine Landing Boat

By Carl O. Schuster
11/18/2011 • Vietnam Magazine

At 0200 hours on June 3, 1972, America’s last POW rescue attempt began when Lt. j.g. Mark Lutz guided a Mark 6 swimmer delivery vehicle (SDV) away from the submarine Grayback, submerged just outside the mouth of North Vietnam’s Red River. Lutz was to deliver two U.S. Navy SEALs, Lieutenant Melvin Dry and CWO Philip Martin, to a small island approximately 4,000 yards away to await the arrival of two U.S. POWs who were to escape their camp by boat. It was a daring secret mission made possible by the only U.S. Navy submarine capable of covertly delivering Marines or Special Forces to an enemy shore.

Originally designed to house the Regulus sea-to-surface missile, the Grayback was modified in 1967 to transport a SEAL team and their equipment, including the secret “Swimmer Delivery vehicle” (SDV). (U.S. Navy)
Originally designed to house the Regulus sea-to-surface missile, the Grayback was modified in 1967 to transport a SEAL team and their equipment, including the secret “Swimmer Delivery vehicle” (SDV). (U.S. Navy)

Commissioned in March 1958 as the lead unit of Regulus cruise missile carrying submarines, the advent of Polaris missiles led to Grayback’s modification and 1968 re-commissioning as an amphibious personnel transport. It received the designation LPSS-574 (for Submarine, Landing, Personnel). The alterations included lengthening the hull to accommodate two auxiliary fuel tanks forward of the engine room, extending the sail by 10 feet and converting the missile magazines on the bow into a dry deck shelter capable of embarking up to 67 troops and two SDVs. The shelter had a special bulkhead to enable underwater launch and recovery of the troops and SDVs. It also had a decompression chamber installed in the starboard missile hangar location. However, SEALs reported that the shelter’s designation as “dry” was at best an exaggeration as it was always damp and humid. Another negative aspect of its design was the air venting, which routed air from the sub’s head through the shelters when the submarine snorkeled to re-charge its batteries.

The hull expansion and alterations reduced Grayback’s speeds by about 2 knots. Although slow when submerged, it was extremely quiet when operating on batteries. Its comparatively small vertical size made it ideal for operations in the relatively shallow South China Sea and coastal waters off Vietnam.

Most of Grayback’s missions during and after Vietnam remain classified. It reportedly conducted its first covert mission of the war in 1971, but the recent release of details about Operation Thunderhead ensures that it will be best known for its key role in that POW rescue attempt, even though it failed. Unexpected currents and poor navigational information precluded Lieutenant Lutz reaching the island before the SDV’s batteries ran out. The SEALs had to abandon it and be rescued by helicopter, sinking the SDV before they departed. Lieutenant Dry was killed while trying to return to Grayback by helicopter, and the rescue mission had to be aborted.

Grayback remained active in Asian waters for another 12 years before its aging equipment and a lack of spare parts led to its 1984 decommissioning. It was sunk as a target off Subic Bay, Philippines, on April 13, 1986. However, its activities during and after the Vietnam War convinced the Navy of the need to retain Grayback’s capabilities. The development of Detachable Dry Deck shelters began in the 1970s, and the first Los Angeles-class nuclear-powered submarines were modified to carry them in 1987. Grayback may be gone, but its capability to support special operations forces lives on in the design specifications and construction of every U.S. Navy submarine built since the 1990s.

USS Grayback 

Max. speed (surfaced):  14 knots

Max. speed (batteries): 13 knots

Cruising speed:  4-6 knots

Surface propulsion:  Diesel-electric

Displacement (surfaced):  2,768 tons

Displacement (submerged):  3,638 tons

Crew:  12 officers/77 enlisted

Armament:  16 21-in. torpedos


First published in the October 2011 Vietnam magazine. Subscribe today!

25 Responses to Arsenal | USS Grayback: Secret Submarine Landing Boat

  1. William Douglas says:

    I served on board Grayback from 1971-73. I remember operation Thunderhead, as well as other special operations we carried out with Seals, Recon, and R.O.K. trops. The crew and officers were the best. If not for our Capt. JD Chamberlain, Lt Dry’s death would still be classified as a training exersize, not killed in action during war. I miss the old girl, and my time aboard her. Doug.——-D.B.F.———–

    • cpl D.Gutierrez says:

      i was on board the grayback for 3 weeks from aug on board at yakusca japan.a1/42nd plt 3rdmardivwestpac fmf

  2. Bluemex says:

    Ditto Doug my best out of four in my twenty seven years the concet will not be the same unless they build it like it.

  3. William Hardwick says:

    As a young Marine I was fortunate to have sailed on the Grayback with 66 brother Marines in early 1972. I thank the crew for their most gracious hospitality. I was only on board for a couple of weeks but it was long enough to be convinced that should I remain in the service it would be as a submariner. Doug and Bluemex we probably met while I had the privilege of sharing your home on the seas thanks again ……Bill. Sempre Fi

  4. James DeFrain says:

    I was on the grayback for training between 1981 and 1983 we launched our IBS did our mission then hooked up with the other teams and stretched a 120 line and waited for the periscope to catch the line. Man what a ride! It was also the best food I had while in the military. 3rd Recon. Sempre Fi

  5. Jim Stevenson says:

    I served on board the Grayback in the ’70s and was the best time of my whole Naval career.

  6. Tom DeRossett Cpl. USMC 1969-1972 says:

    Iwas posted TAD for Raider Training after extending with 7th Comm Bn Oki in early 72, several training programs were opened to non-grunt units to cross train non 0300 mos. personnel. Raider Training and the Army Jump School were highly sought after billets. The training mission on the USS Greyback as part of the training was the highlight of the entire program. If you look closely at the dates you might determine the USS Greyback was preparing for their POW rescue mission in June of 72. Anyone remember they showed the movie “Shaft” while on the exercise?

    • Randy Madrid says:

      I don’t really know if I remember “Shaft” showing in the galley, as I’d seen it several times stateside before boarding the Grayback. (I do remember seeing “Billy Jack” and some chick vampire movie. Haha.

      Were you one of the Marines who rendezvoused with us by way of air drop via helo? That was really impressive seeing Marines jump out the back into the ocean.

      Tragically, that’s what later killed LTjg Dry on the op.

  7. James Shane says:

    Lest we forget LPSS 315 USS Sea Lion

  8. Tamara says:

    Does anyone have any parts or memorabilia from The Grayback?

    • David Willenborg says:

      Yes, I have a sight glass from one of the stern tubes, and I have the forward torpedo room ashtray. Last, I have a union jack that she flew the day before he decom.

  9. Danny Macalanda says:

    During the Vietnam War, U.S.S. Grayback was a regular visitor at SRF, Subic Bay, Philippines. We used to work on Her AN/SPN-32 – An/WPN-4 Loran Charlie. A very memorable sub.

  10. Clint Steffensen says:

    I served on the Grayback from 1982 to 1984 and was also on decommissioning crew I was a spec. warfare diver attach to the Grayback working with SEAL, UDT, EOD, RECON, and R.O.K. is something I will remember till the day I die.

  11. Anonymous says:

    Hello. I’m looking for some information about the U.S.S Grayback if anyone can help me out, my father always told me stories of when he was in the Marine Corps. Almost all which include stories of his time aboard the U.S.S Grayback. Anyway, I’d like to find out if anyone who was on it between 1970-72 would know him or who could just tell me other general stories about that time aboard the ship and if they have any kind of memorabilia from those days aboard !.. thank you to anyone who may read this and reply. It would mean the world to me.

    • cpl D.Gutierrez says:

      It was bad weather out side the sub,and it was tossing and listing left and right uo and down,and most of the marines.were sea sick.we couldnt hold down any chow.we’d come down from tube,down the ledder and the head was right in front of you ,as we made our way to the mess hall you. could see.the sailors eating crackers and cold cuts will we the marines drank the milk an food.and on the way up to the tubes or sleeping quartres.we passed by the head and throw up and back to bed until fur notice.

  12. Richard Kapszukiewicz says:

    I was a plank holder and was on the Grayback 1968 – 1972….What a ride……Will always remember the crew….and the experiences….I was a STS3(SS)

  13. Michael Jordan says:

    I served on the USS Grayback LPSS-574, from 11/80 to 03/82. I was an STS 3 SS/DV, and was on board the night of 1/16/82 when 5 individuals died. I will never forget that night and the lost of my 3 shipmates and the UTD/SEALS. There were friends, and though I might never know the loss their family felt, I am sure time will never erase that.

  14. Randy Madrid says:

    I also served aboard the Grayback from 1971-1973 and remember LTjg Dry and Operation Thunderhead, and also taking a warning round from the USS Long, I believe.

    And I remember Doug and BlueMex (the knife maker). The Grayback had been home-ported in Subic Bay for some years and acquired an interesting crew.

    Then there were the training ops with the Marines! It took me quite awhile to get my sea legs, but a bunch of sea sick Marines was dangerous! The head in Forward AMS was right below the hangers and you had to watch out for puking Marines. Semper Fi, guys!

    Those were some crazy interesting times. I shoulda shipped over!

    Fair winds and following seas.

  15. Rich McFadden says:

    I was on the Grayback in 1975 for training while in the 3rd Recon Div. USMC. I remember the food was great. No one in our scuba recon platoon got sea sick. Subic Bay was like Disney Land for us after being cooped up on the Rock. Rich McFadden- Semper Fi

  16. Jesse Ortega says:


    I was the photographer on one of the Grayback training ops with 3rd Recon. Do you remember Captain Wesley Fox?

  17. BOBBIE A. BUDEAU says:

    rode her oct 58-dec 62 (qual boat). later 70-75 as staff rider while
    stationed at csf-7.

  18. LTJG Brian S Kagy says:

    I would have been the OOD who snagged you.

  19. BOB BUDEAU says:

    enlighten me pls. tks

  20. Dmitry says:

    Hello! I am a retired Soviet/Russian submariner. I investigate an accidents when in 1967 Russians dropped new secret mines RM-2G in the Pacific and later the mines were picked up by US “special forces”. A couple of months later the mines were demonstrated in New York… a few Russian sources claim Grayback team as heroes who did this job. As I understand Grayback had not been commissioned yet in 1967?
    In any case I would be really thankful for any links to declassified information of the case!
    Regards! Dmitry

  21. David Swiger says:

    Trained on her in 1972. Best chow I ever had in the service was cooked by her “chef” (a huge sailor but fantastic cook). Which I still had the pictures from back then. That was the best shipboard experience ever. Semper Fi

Leave a Reply

Your email address will not be published. Required fields are marked *

, , , , , , ,