"One Boat Wolf Pack"

   As WAHOO’s crew basked in their newfound celebrity, their captain, Mush Morton, was already looking forward to returning to sea.  His boats' performance off New Guinea had indeed been spectacular. He was eager to prove that it hadn't been a fluke. Following a refit which included moving the stern mounted 4" gun forward of the conning tower and installing a third 20mm mount in its place, WAHOO departed Pearl Harbor on February 23, 1943 barely two weeks after her triumphant return from her third patrol.
   Traveling on the surface, submerging only for training and trim dives, WAHOO entered Midway on February 27. Stopping only long enough top off with fuel and water, they departed for their patrol area the same day.
   Despite encountering rough weather and head seas, Morton refused to dive. Without a single enemy contact, WAHOO steamed the entire distance to her patrol area, some 4,000 miles, on the surface. She arrived in the China Seas on March 11, 1943. Hoping to encounter heavy merchant traffic bound from China to the Japanese home islands, Morton pressed into the shallow waters of the Yellow Sea. Previously unexplored by American submarines, he planned to blaze a trail of sinking merchant ships. He just had to find them.
   On the 13th, smoke was spotted on the horizon at 0800. Morton gave chase for five hours without closing closer than 8,000 yards. Frustrated, he broke off the approach. Three hours later the heavily smoking target reappeared. Morton closed, firing a single torpedo. It missed ahead due to an error in the firing solution. Morton withdrew and let this strange craft go. A small inter-island steamer either trawling or patrolling, Morton dubbed him “Smoky Maru”. Barely worth a torpedo, Morton had fired at him because he was, in his own admission, “anxious to shoot something”. 
   Over the next six days, WAHOO sighted several Smoky Marus and numerous sampans. He patiently avoided each one. On the 19th, the fireworks began in earnest with the sighting of a 4,000 ton freighter, ZOGEN MARU, at 0430. Morton fired a single torpedo. It disintegrated the after part of the ship. The forward part sank in two minutes, 26 seconds. 
   Four hours later they sighted another freighter, the 5,900 ton KOWA MARU, and gave chase. Firing two torpedoes, the first hit under the foremast with a tremendous blast. The second was a dud, striking amidships. With the target still underway, Morton fired a third fish. The target spotted it and maneuvered out of its path. Firing a fourth fish up her stern, KOWA MARU avoided it as well and began firing at WAHOO’s periscope. As the water was so shallow and the threat of patrol boats was imminent, Morton reluctantly let his wounded prey go. It would not be learned until after the war that KOWA MARU sank soon thereafter, becoming WAHOO’s second victim. 
   Two days later found WAHOO partaking in another daily double, starting with the sighting of a Seiwa Maru class freighter at 0700. This ship, HOZAN MARU, received a spread of three torpedoes, one of which struck her amidships with a tremendous explosion. Within four minutes she was gone. Closing the wreck site, the bridge watch counted thirty-three survivors in the 40 degree (F.) water. 
   At midday, a second freighter appeared on the horizon; the NITU MARU. Firing another spread of three fish, two struck home beneath her bridge and mainmast. Again, the detonation was unusually strong and the ship headed down vertically by the bow. As her stem struck the shallow bottom, her stern remained
poised majestically in the air. Lt. Chandler Jackson, taking over as ship's photographer from the departed George Grider, snapped several pictures. NITU MARU's stern settled back and she was gone in three minutes, ten seconds. 
   Closing the scene of their latest success, Morton spotted four survivors perched on wreckage, wringing the frigid water out of their clothes. As Forest Sterling would later write, their actions moved Morton to comment: "They're pretty smart". Desiring to take one of the men prisoner, he nudged WAHOO close.
Hailing in English, WAHOO's men ordered them to climb aboard. The Japanese turned their backs to the enemy submarine and refused. 
   Morton then spotted several books floating nearby. He ordered them collected in the hope that they were codebooks. At the same time, they hauled aboard what would be even more highly valued by the crew: two flags from the recently sunk freighter's shipping line. Grabbing a final item, the men pulled
from the water a life ring inscribed "NITU MARU - TARUNI".
   Morton changed course to clear the area and to throw off patrols responding to his attacks. Enjoying his success, Morton calculated that this virgin territory would yield four more sinkings. He further planned on expending his gun ammunition on targets of opportunity as they returned home. The remainder of the patrol would not prove him wrong.
   Just before dawn on the 23rd a coal collier of 2,400 tons was spotted. Morton fired a single torpedo which hit under her bridge and enveloped the target in a cloud of coal dust. Thirteen minutes later, the ship was gone. Morton cleared the area as a Smoky Maru chugged out to the scene and dropped several depth charges in the distance.
   After a day of patrolling on the 24th radar reported a contact. Tracking into the dark night a large tanker hove into view. It was identified as TAKAOSAN MARU, 7,400 tons. Approaching on the surface, Morton fired three torpedoes. The first two detonated prematurely eighteen seconds into their run. The third missed. Morton fired another. It missed as well. Suddenly the target opened fire. A shell bursting directly ahead of WAHOO forced her to dive. 
   Undaunted, Morton surfaced, pulled ahead of the randomly firing tanker and dove. As it approached, WAHOO launched three torpedoes. The second fish struck  the fully loaded tanker in the engine room. She  sank in four minutes, 25 seconds. But the night was not over.
   The light of a ship was spotted on the predawn morning of the 25th. Maneuvering into position, Morton fired two torpedoes. Both detonated prematurely. Tremendously frustrated, Morton ordered “Battle surface” and opened fire with his 4” and 20mm guns.  After taking 90 rounds of 4” shells the freighter, identified in the recognition books as SINSEI MARU, was soon a burning, listing wreck.  However, calls from his lookouts reporting another ship moved Morton to cease fire and approach the second vessel. As they withdrew, WAHOO’s crew called out “So solly, please!” to the SINSEI MARU’s crew.
   Closing quickly, Morton opened fire with his deck guns on the 1000 ton cargo ship SATSUKI MARU. Eighty 4” rounds set it ablaze. As they sent SATSUKI MARU to the bottom, the Quartermaster reported the SINSEI MARU had also sunk. Morton cleared the area. He now had two torpedoes left and was none too confident that they would not explode prematurely like his last two fish.
   At noon, a tantalizing target appeared on the horizon, a large passenger ship. Although they tried their best to close, the target reversed course and WAHOO could not get any closer than 12,000 yards. Then, possibly alerted by the liner, a destroyer appeared on the scene, range: 8,000 yards. Prepared to fire a defensive down-the-throat shot, Morton slunk away, none too confident in his ordinance. He set WAHOO on a course to follow the coastal shipping lanes south of Kyosho in the direction of home.
   Perhaps frustrated at losing the passenger ship, Morton surfaced to fire on a trawler with his 20mms. Possessing a large radio antenna, the gun crews worked the small craft over. Bringing “WAHOO’s  Commandos” on deck, Morton allowed Ensign George Misch and Chief Lane to hurl molotov cocktails into the hold of the trawler. Specially prepared by Marines at Midway and given to WAHOO for the purpose, they created impressive initial explosions. However, they failed to ignite the waterlogged vessel and they left her behind.
   Heading for home, on the 28th Morton battle surfaced on two sampans and worked them over with his 20mms. In his report he remarked with disappointment that the seas were still too rough to go aboard and capture a “mess of fresh fish”. Yet with all this diversion, the patrol was not yet over. 
   Early on the morning of the 29th, a large ship was sighted, YAMABATO MARU. Tracking began. At 0419 WAHOO’s last two fish were fired. The first struck home under the mainmast and “disintegrated everything aft of her stack”. The second missed because its point of aim, the foremast, was stopped “dead in its tracks” by the first torpedo’s blast. With her tubes now empty, Morton turned WAHOO for home.
   The following day a potentially disastrous accident struck. While running on the surface, an “unusual” swell pooped the main induction and shorted out the electrical cubicle in the maneuvering room. All power was lost and WAHOO ground to a stop. Lying to in enemy waters and far from any assistance, feverish repairs restored power and the acrid smoke issued by battery shorts was sucked from the boat. By the 31st the engines were back in good operating order. The crisis behind them, insult was added to injury by a message directing Morton to return to Midway Island for refit rather than continuing on to Pearl Harbor. 
   On April 6, with NITU MARU house flags, sixteen victory flags and “battle cry” pennant flying from her periscope shears, WAHOO returned to the submarine base at Midway Island. Mush Morton’s excursion into the unexplored territory of the Yellow Sea had set a record: nine ships sunk on a single patrol. It would stand for almost a year, only to be broken by his co-approach officer, Dick O’Kane, in his own command.
   As the crew was feted to the best of Midway’s limited ability, Morton was flown on to Pearl Harbor. There he gave a first hand report of his activities to an enthusiastic Admiral Charles Lockwood, Commander of Submarines, Pacific. His torpedo problems, the prematures and duds, were overshadowed by his outstanding success, achieved in spite of them. Had his munitions worked as designed, his score, like many of his contemporaries, could have been even greater. 
   As it was, Lockwood informed him that Japanese communiqués shrieked with tales of a fleet of submarines operating in the Yellow Sea. “Mush,” glowed Lockwood, “You’re a one boat wolf pack!”