Tuesday, April 07, 2009

New Picture and Information about the SWORDFISH Test

On 11 May 1962, Razorback participated in the "SWORDFISH" nuclear weapons test. An ASROC (Anti-Submarine Rocket) with a nuclear depth charge warhead was fired by the destroyer Agerholmn (DD-826) at a target raft from a range of 2 nautical miles. Razorback was submerged at periscope depth 2 nautical miles from the target raft. The ASROC weapon produced a powerful underwater shock wave which visibly shook Razorback and her crew. The resulting data was used to formulate tactical doctrine for ASROC, a weapon that remained in front-line service for nearly 30 years.

Recently, Rod Potter wrote us about his experience aboard Razorback during the SWORDFISH test in 1962:
I was in the Razorback at the time, serving in some principal capacity that I don't recall (probably Weapons Officer). One of my collateral duties was photography officer and I was tasked to get a photograph through the periscope. Prior to the actual test, we had some preliminary trials to familiarize the crew with the sound and feel of an underwater explosion. So we did one or two submerged runs near a place where a fairly large chunk of TNT or similar explosive was set off. It was enough to give us a pretty good jump.

On the day of the test we were positioned either at 2,000 yards or 4,000 yards from the target point. (I don't remember which, but more likely it was 4,000 yards). [Editor's note - it was 4,000 yards, or 2 nautical miles] We were submerged at periscope depth, and I was manning the #1 scope to which the camera was rigged. Periscope photography in those days was still pretty primitive. To gauge the correct lens setting for the 35mm camera, I first used high speed film in a Polaroid pack, judged whether that exposure was too light or too dark, attached the 35mm single lens reflex camera and then manually adjusted the lens accordingly. I accomplished those preliminary tasks, but since I cautiously did not wait to do it at the last minute, I could not be sure that the light conditions at the moment of the explosion would be the same.

We all waited nervously, with the boat rigged for collision, not really knowing what to expect. Crew members had been assigned to monitor hull fittings throughout the boat to be ready for potential failures. We had been reassured, of course, by those conducting the test, that all would be well.

At zero hour, the Captain on the #2 scope and I on #1, could see the first evidence of the explosion, a slight rising of the water at the site as the shock wave reached the surface. Shortly thereafter, the first direct wave hit the boat as if we had been struck by an enormous hammer. Seconds later, we were struck by a second wave that had bounced from the bottom, which as I recall, imparted some vertical motion to the boat. While this was happening, I was poised to catch the moment when the plume of water caused by the heat of the explosion would push to the surface, but I was thrown into momentary confusion because the shock waves caused the periscope to cycle up and down on its own. I quickly got it under control, and snapped the only picture I was able to get.

The photograph shows the plume a second or two after it reached its maximum height, and the exposure is a bit darker than optimum. Its authenticity is marked by the photograph of the periscope clock in the upper corner.

Razorback sustained no damage other than a pipe fitting or two that sprang leaks.


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