Within five minutes, the frigate's helo was five miles out, dropping Lofar-type sonobuoys. On striking the water, these miniature passive sonar sets deployed a non-directional sonar transducer at a preselected depth. In this case all dipped above the thermocline layer to determine if the target was close. The data was relayed back to Pharris's combat information center: nothing. The passive sonar track, however, still showed a submarine or something that sounded like a submarine. The helo began moving outward, dropping sonobuoys as it went.
Then the Orion arrived. The four-engine aircraft swooped low along the frigate's reported bearing-to-target. The Orion carried over fifty sonobuoys, and was soon dropping them in sets both above and below the layer.
"I got a weak signal on number six and a medium on number five," a sonar operator reported. Excitement crept into his voice.
"Roger, confirm that," the tactical coordinator on Bluebird-Three agreed. He'd been in the ASW game for six years, but he was getting excited, too. "We're going to start making MAD runs."
"You want our helo to back you up?"
"Roger that, yes, but tell him to keep low."
Seconds later the frigate's SH-2F Sea Sprite helicopter sped off north, her magnetic anomaly detector trailing out by cable from a shroud on the right side of the aircraft. Essentially a highly sensitive magnetometer, it could detect the disturbance in the earth's magnetic field made by a large chunk of ferrous metal-like the steel hull of a submarine.
"Signal on number six is now medium-strength. Signal on seven remains medium." The plotting team took this to mean that the submarine was heading south.
"I can give you a working range figure," ASW said to the TAO. Forty-two to forty-five thousand yards, bearing three-four-zero to three-three-six." The frigate relayed this at once to the Orion.
As they watched on radar, the P-3C quartered the area, flying very precise tracks across the box of ocean defined by Pharris's sonar data as the probable location of the submarine. A computer system plotted the lines as they extended to the south.
"Pharris, this is Bluebird. Our data indicates no friendly subs in the area. Please confirm, over."
"Roger that, Bluebird. We confirm no reports of friendlies in the area." Morris had checked that himself half an hour before.
"Signal strength increasing on number six. We now have a weak signal on number five. Number seven is fading out." The technician was really struggling to be professionally impassive now.
"Range is firming up. Estimate target speed roughly eight knots, distance forty-three thousand yards."
"Transient! Transient!" called the ship sonar operator. A metallic noise had come from the target bearing. A closing hatch, a dropped tool, an opening torpedo tube door-something had made a uniquely man-made sound.
"Confirm mechanical transient, copied on buoys five and six," the aircraft called immediately.
"Confirmed," Pharris's TAO answered. "We got that on the towed array, too. We evaluate the contact as positive submarine at this time."
"Concur," the Orion replied. "Positive Redboat classification-madman! Madman, madman, smoke away! We have a NLAD contact." A big spike appeared on the MAD readout. Instantly, a crewman flipped a switch to deploy a smoke marker and the aircraft turned hard right to circle back on the contact point.
"Plotted!" The tactical action officer marked the position on his tactical display scope with a large V symbol.
The helo raced in on the contact as the Orion circled back.
"Madman!" its systems operator called out, and the helo dropped its own smoke bomb, slightly south and west of the Orion's.
The data was now being relayed to the frigate's torpedo-tube and ASROC attack directors. Neither had anything like the range to engage the target, but that could change quickly.
"Patience," Morris breathed from his chair in the CIC, then louder: "Take your time, people. Let's lock this guy in before we fire."
The Orion's tactical coordinator agreed, forcing himself to relax and take the time needed. The P-3 and the helicopter made another MAD run north to south. This time the Orion got a reading and the helo did not. Another run, and both had the contact's course line. Next came an east-to-west run. At first, both missed, but on the second run both had him. The contact was no longer an it. Now it was a he, a submarine being driven by a man. Control of the operation now passed exclusively to the tactical coordinator on the Orion. The big patrol aircraft orbited two miles away as the helicopter lined up for the final pass. The pilot made a very careful check of his tactical display, then locked his eyes on the gyrocompass.
The helo began the last MAD run, with the Orion two miles behind it.
