In the Conning Tower Captain Mealey turned to Lieut. Bob Edge, who was at his station at the TDC, the Torpedo Data Computer.
“Pass the Is-Was down to the Executive Officer,” Mealey said. “I don’t want to clutter up the TDC with the preliminary sonar plots.” Edge nodded and took the celluloid “banjo” from a knob where it hung by a loop of cord. Before the development of the TDC the Is-Was had been the only fire control tool a submarine captain had at his disposal to work out the complicated mathematical problem in order to fire a torpedo at a target. Edge bent down and dangled the Is-Was by its cord and Sirocco took it and hung it around his neck.
“Let’s begin the preliminary shooting plot, Joe,” Captain Mealey called down from the Conning Tower. “Let me have your first plot as soon as you have it.”
Cohen nodded at Sirocco and watched his dials and made notes and then he began to feed a steady stream of information to Sirocco and Grilley, who worked rapidly over a plotting sheet. Sirocco reached for the Is-Was and began to work out the problem on the plotting sheet. He looked upward at the Conning Towel- hatch.
“We have the target steady on a course of two three zero, sir. That jibes with the course we assumed it would take to make its entrance to the atoll.
“Our planned point of intercept is eight hundred yards from the target’s course into the mouth of the atoll with an intersect angle of ninety degrees.
“We have been on our intercept course to that point for some time, now. We should be at our shooting point in thirty-seven minutes, assuming a torpedo run of eight hundred yards, sir.
“If we assume the target was one mile astern of his van when we sighted the masts of the van, that is, the target was seventeen miles distant when we dove and that he was making fifteen knots, as the intelligence report said he would probably make, the target should be at the point of intercept in thirty-seven minutes, sir. With all due respect, sir, our timing is too tight. We have no allowance for planing up for a periscope observation, no allowance if the target decides to change course or speed. Mr. Cohen says we have a good fix on the target so you wouldn’t have to waste any time if you went up for a look, sir.” The hint in his words was just a trifle stronger than it should have been and the people in the Control Room and Conning Tower recognized that Sirocco was telling Captain Mealey what to do. Don Grilley raised his head from the plot and looked at Sirocco, his eyes widening, and then he bent his head to the plotting sheets.
“Very well, Mr. Sirocco,” Mealey’s voice was edged. “I plan to make two observations before we begin to shoot. Mr. Cohen, give me a bearing on the battleship.” Asking Cohen for the bearing rather than asking Sirocco to get it from Cohen was an implied rebuke to Sirocco, and the people listening recognized that, too. Cohen let his head drop on his chest, concentrating on sorting out the clutter of sounds filling his earphones. He spoke softly into the telephone microphone he had hung around his neck.
“Main target, designated as Alpha, bears three three seven, sir. Repeat: three three seven.”
“Make turns for four knots,” Captain Mealey called. The helmsman moved his annunciators and Mealey heard the click of the response from the Maneuvering Room as Hendershot moved his pointer to match up with the order.
“Making turns for four knots,” the helmsman said.
“Very well,” Mealey said. “Bring me up to sixty-five feet, Control. I will take no more than seven seconds for this look. Begin planing back down to two hundred fifty feet after I’ve been up for seven seconds.”
“Six five feet, sir,” Simms said from his post in the Control Room. “Return to two five zero feet seven seconds after we reach six five feet, aye, aye, sir.”
At 65 feet Mako’s periscope would be 18 inches out of the water. From that height the horizon would be only a little more than a mile and a quarter away. But the battleship, with its lofty superstructure and towering masts, would be visible from a distance of more than 10 miles.
If the target had been traveling at the speed the intelligence report said it would travel; if Mako was not detected as it rose to make the periscope observation; if Captain Mealey could get an accurate range on the target and get the “angle on the bow” so the target’s course could be determined as a check on the sonar bearings; if Mako could get back down to 250 feet, then Captain Mealey and Joe Sirocco would have a set of accurate data on which to base the solution of the torpedo problem.
The telephone talkers passed the word in whispers throughout the ship that the Captain was going up to take a look and there was a dead silence in Mako as the ship planed upward through the water. This was the first of what could be a number of crucial moments. If a patrolling aircraft saw Mako’s long, dark shadow beneath the surface of the clear water, if the white feather of the periscope’s wake attracted the eye of a lookout on a destroyer, the long run to get into position would be wasted and Mako would be the target of a dozen destroyers and no one knew how many aircraft as the target, the battleship, alerted, sped for the safety of Truk Atoll.
“Make turns for two knots,” Captain Mealey said as the depth gauge showed 110 feet. “I’m going to raise the scope at eighty-five feet, Control, watch your angle when I do.” Raising the periscope would create a drag that would tend to tip Mako’s bow upward more than desired.
Mealey squatted down by the periscope well and raised his left palm upward as a signal to Paul Botts to raise the periscope. Botts pushed the button that raised the periscope and stopped it as the periscope handles cleared the deck. Mealey snapped the handles outward and rotated the periscope until the lenses were in line with the last bearing given by Cohen.
“Seven zero feet and holding a half-degree up bubble,” Simms reported from the Control Room.
“Very well,” Mealey said. “Up periscope!” He clung to the handles, his face pressed against the heavy rubber eyepiece, his forehead tight against the rubber bumper above the eyepiece, clinging to the periscope handles as it rose upward.
“Six eight feet! six seven feet!” Simms chanted. “Six five feet, sir, and holding!”
“Mark!” Mealey snapped.
“Bearing — three three eight!” Botts sang out. Captain Mealey was rotating the range finder knob below the right handle of the periscope.
“Range! One three zero zero zero yards! Angle on the bow one five starboard! Down ‘scope! Take me down, Control! Fast! Aircraft on our starboard beam! Two destroyers bearing zero two five! Hard Dive! Hard Dive!”
“Six seconds!” Grilley said, looking up from the stop-watch that hung around his neck on a cord. “That is one damned fast periscope observation!”
“You’re not kidding,” Sirocco grunted. He plotted the position of the target and fiddled with the Is-Was.
“Everything is on the nose, Captain,” he reported. “The target has to run twelve thousand yards to the point of intercept. The target will reach that point in twenty-five minutes!”
“Two five zero feet, Captain,” Simms interrupted. “Making turns for four knots, sir.”
“Give me your recommended speeds, Joe,” Mealey asked.
“We will be at the shooting point in fifteen minutes at this speed, sir,” Sirocco answered. “We’ll have too much time to stooge around. Recommend we run at four knots for eight minutes and then slow to two knots. We should be able to come up at our shooting range of eight hundred yards at that point.”
“Very well,” Captain Mealey said. He turned to Edge.
“Work that out on the TDC.” Sirocco heard the order and his craggy face flushed slightly.