One of the first things that I learned as part of my military officer training was “Do not, under any circumstances, volunteer for anything”. This was especially true in January 1971 at the height of the Vietnam war. But, through a rather circuitous route of give and take between the army and navy, a short time later I found myself in the eastern Caribbean standing on the heaving deck of a navy research vessel as the executive officer explained the exercise he wanted from the dive team I had been assigned to.
And the more he detailed the concept, the more I wondered if I would have maybe fared better in a rice paddy in southeast Asia. But that decision was behind me and the immediacy of the task facing us as members of the dive team drew quickly into focus.
The navy was making every effort to “silence” the fleet of fast attack nuclear submarines that hunted the Soviet missile subs called “boomers”. The attack subs’ mission was to seek out and destroy, if necessary, the enemy missile subs and they accomplished this by remaining as stealthy as possible. This meant minimizing every conceivable noise that might be emitted from the sub’s machinery, reactor plant, plumbing, even sounds that might be generated by galley appliances and crew movement. One of the largest sources of traceable noise was produced by the massive single propellers that hurled the vessels through the dark abyssal plains of the world’s oceans.
It’s one thing to get a submarine quiet when it’s running at slow speeds. But it’s quite another story to maintain detection security when underwater speeds could exceed 50 knots.
But the navy had some pretty bright engineering experts who had figured out that the key to reducing noise in these racehorses was to manage the wake vortex created by the propeller, dive planes and rudder. The wake vortex was a phenomenon that was visible to the human eye. This “corkscrew” trail followed the sub and created an acoustical signature that was detectable by Soviet submariners through hydrophones and other listening equipment. Our mission was to film the wake vortex and provide the engineers back in the labs with a visible film model to effect modifications to the U. S. subs and help make them quieter. It all sounded so reasonable in the briefing room.
We had already had great success with our films of the fast attack subs creeping silently along at crawl speeds. A few tweaks here and there and the damn things were virtually undetectable. But as part of their tactics in stalking the Soviet boomer fleet, it was necessary for the hunters to make brief speed bursts to get ahead of the enemy craft and then lay silent as they approached. You probably remember some of this from the various Hollywood movies dedicated to this genre of war drama. But no matter what era, World War II or the modern Cold War, the key elements to military tactical success in submarines were remaining quiet and undetected in order to kill the enemy.
Our dive team originally had worked with the hydrophone listening devices deployed from navy P3V Orion aircraft whose mission was to detect enemy boomers from the air. These massive four engine turbo-prop bombers would swoop low over the target area and drop dozens of canisters (that looked kind of like little bombs) in a patchwork grid of the ocean. Upon impact, the canisters exploded a floatation buoy and deployed their hydrophones to depths sometimes deeper than 300 feet. If everything worked okay, the technicians could now monitor any sub activity and track the intended targets.
In fact, we had gotten so efficient at the hydrophone work where we filmed deployments and actual functions of the devices at depth, that the lab guys in their nice neat white coats had decided to ask us to take over filming the passes of the fast attack subs.
Actually, we got the job after an attempt to use small submersibles failed dismally. Most of the time the external movie camera mounts seemed to end up pointed the wrong way or they jammed before the spool was completed. And then there was the almost fatal incident where one submersible lost ballast control and nearly sank to the bottom in over 12,000 feet of very dark ocean trench. No one was too eager to jump back into the tiny one-man submersibles after that.
So the torch fell to the dive team. And that’s why I found myself listening eagerly (and apprehensively) to the exec as he “chalk-talked” us through the plan step by step. When he was finished, the three of us sat there in our neat khaki shorts and asked politely for him to repeat the speech. We were sure that we must have misunderstood something along the way. It was just too crazy…
Here’s the scenario: they wanted us to descend to 250 feet and form an equilateral triangle with about a hundred feet between each man. We would then hold that position while a fast attack sub threaded the needle between us as we filmed it.
And, oh yeah, we’d start the drill off at 20 knots. Any questions?
Well, yes, we did have one or two little concerns. Like how were they going to avoid running us over and grinding us into fish food pellets? And what was going to happen to us once the sub passed and we were left to flounder in its considerable wake? Vortex my ass, this sounded a whole lot like a plan dreamed up by Pentagon geniuses who lacked, shall we say, a certain feeling for conditions in the “field”.
The exec smiled and reminded us that the key to the generous retirement program was surviving long enough to actually be eligible for the benefits. Catch-22 lives on. Just call me “Yossarian”.
A officer from the sub we would be working with explained that we would be equipped with sound locators that allowed the sub to precisely fix our positions and allow them to maneuver through our “target area”. That was a real comforting term to us. He noted that we would do a walk-through drill at slow speed first to let them set their navigation systems up on us before “winding her up” for the actual film pass. About then I was feeling more than a little “wound down” but we adjourned to the dive deck and began preparing our gear.
By one o’clock we were all ready to go and slipped quickly into the water with our bulky 16mm movie camera housings. The ever-present oceanic white tip shark population swam up immediately to greet us. After a few banged noses and punches to the gills, the sharks back off enough to let us split up and get into position.
We left John Hood at about 150 feet where he formed the top of the triangle. Pat Romano and I swam away from him to the prescribed distance and then dropped to 250 feet as the sub waited patiently in the blue gloom. Once set up, the sub eased through our pyramid without incident with about twenty-five feet of clearance on Pat and me. John was barely clearing the conning tower (or sail) so he moved up another ten feet or so after the requisite communications with the sub crew.
And then we were ready. The sub moved off into the blue and disappeared. They would give us a sonar ping when they began their run so we had some idea of when to start running the film. We hung nervously in the water column and waited. After what seemed like hours, but was really only minutes, we heard the ping. And felt it. Getting an active sonar ping underwater is about like being belted by an NFL defensive end. Please sir, can I have another?
We counted off ten seconds and jammed our thumbs on the camera housing triggers. The 16mm Bolex gears hummed efficiently as we stared into the empty void. In the open ocean visibility can exceed 200 feet but we never actually saw the sub as it screamed by us. You had the vague idea of a dark shape appearing out of the blue, but before the human eye could focus, it was on us and racing past. We stared at the fifty-foot high arcs created by the wake vortex and grinded away with the film.
About then the effects of the wake turbulence were felt by Pat and me. He was hurled up and to the south while I was thrown like a limp rag to the north and down by the power of the massive right-hand rotating prop. Pat ended up nearly level with John at the high side of our pyramid while I found myself watching my depth gauge needle peg itself at 350 feet.
Luckily we had clipped the camera housings to our harnesses… because they were immediately ripped from our grasp like Kobe Bryant’s wife snatched that six carat four million dollar diamond ring from his hand as a peace offering following his marital infidelity a few years back. But, incredibly, we were none the worse for our experience. (And apparently neither was she.)
We rendezvoused at 100 feet and swam up to decompress while fending off the sharks that looked happy to see us. An hour and a half later we struggled aboard. Two days later we all looked at the film. It was magnificent with these beautiful wispy corkscrew trails neatly marking the sub’s path. The sub guys were happy. The engineers were ecstatic. The navy brass was happy. And we were tired. No amount of yoga posturing, herbal supplements, or Zen meditation could really get you ready for the upcoming dives… but a good dose of rum in the local Caribbean bars tended to make the aftermath somehow seem tolerable.
Over the next few months we would duplicate our exercises successfully scores of times. We finally even got to experience what actual flank speed (full ahead) for the sub was like. It was simultaneously thrilling and terrifying. Try standing on the white dotted centerline in the middle of the L.A. freeway sometime … blindfolded. I suggest bringing a change of underwear the first time out.
Bret Gilliam worked on U.S. Navy ASW projects on location in the Virgin Islands and Puerto Rico for eight months in 1971. During that period his dive team conducted a variety of experimental diving protocols that advanced the traditional diving technology of the era.