The need for larger and more powerful diesel engines led to an experiment in larger submarines. The V-4, V-5 and V-6, were given the names of Argonaut, Narwhal and Nautilus. The Narwhal and Nautilus were nearly identical and resembled in most features the Fleet Type submarine.

Narwhal was launched on 17 December, 1929, but not commissioned until 15 May, 1930. She was 371 feet in length and had two 6 inch deck guns. With a hull number of SS- 167 she operated during the 1930s and immediately prior to the Second World War was operating off Wake Island when she developed fuel ballast tank leaks. She had a partly riveted, partly welded hull and rivet problems caused the leak. Returning to Pearl Harbor for repairs she was at the Submarine Base when on December 7, 1941 the Japanese attacked. She and Tautog downed two enemy torpedo bombers and suffered only one casualty.

While during the opening months of the war Narwhal operated as any other submarine and managed to sink ships on her first six war patrols it became apparent that she was far more suited to special operations where her internal capacity could transport people and supplies. Thereafter, she was primarily engaged in clandestine operations along coasts held by the Japanese. It should be noted that while conducting these operations she had authority to sink enemy ships and this she continued to do.

Admiral Ralph Christie controlled the Femantle boats whose mission was to destroy enemy shipping, while Admiral James Fife handled the special missions requested by General MacArthur out of Brisbane. This arrangement was later changed and both Narwhal and Nautilus operated out of Darwin. It was natural for both these boats to perform the special missions since their age and size prevented them from competing with the Gato and later Tench class boats.

On her seventh patrol she delivered supplies at Paluan Bay on November 10, 1943, then proceeded to Mindanao where she boarded 32 evacuees including 8 women, 2 children and a baby. She debarked the passengers at Darwin. This was to become somewhat routine for Narwhal and she again evacuated persons to Australia on her 9th, 10th, 14th and 15th patrols, but it was the 7th patrol that stands out in Narwhal veteran submariner Ben Smith's memory.

Lieutenant junior grade Ben Smith was in Narwhal's wardroom while on the boat's 7th patrol. It was making its way south from Mindanao to Darwin with 32 passengers. Even though Narwhal had been modified to carry non-crew members the encumbrance of many women and children caused some embarrassing moments. The captain, Cdr. Frank D. Latta was enjoying a respite from his duties. He sipped on a cup of coffee and conversed with three of his officers. The pharmacist's mate appeared in the passageway and knocked on the bulkhead. The captain turned and asked about the reason for the doc's grave expression. The First Class Petty Officer explained that one of the ladies was expecting. Cdr. Latta seemed unconcerned until the pharmacist's mate estimate the delivery date to be shy of Narwhal's arrival in Darwin. At this news Captain Latta inquired as to his doc's qualifications in delivering a baby. The response was that he had once assisted while working in a hospital, but that he would need an assistant.

Of the three watch-standing officers in the wardroom at the time, Smith was the last to slide deep enough in his chair to avoid being singled out. The captain told the doc that Smith would assist and for the doc to make all preparations. Smith said nothing. To resist would be futile. He nodded his head.

As the doc headed aft, Smith followed him. He obtained the doc's best ETA which was two to three days. He then bent over the navigational chart on the master gyro table and estimated the ETA of Narwhal in Darwin. It would be close. He rubbed his chin, then went aft to maneuvering and looked at the bell and turn count. Narwhal was making standard on four and Ben suggested that liberty in Darwin had just been upgraded by a new contingent of nurses. The electricians increased the voltage the turn count indicator reflected their anticipation.

As Ben ambled forward through the engine rooms he prayed that no break-downs would occur. In the control room he tried to think of any unturned stone he could examine to extricate himself from the coming ordeal. He and the doc had a serious discussion and laid out a plan of action after which both Ben and the doc paid a visit to the expectant mother. She lay in a middle bunk and through heavy breathing, smiled and said she was doing OK. Ben was doubtful. The lady looked enormous. So much so that an auxiliaryman had removed the upper bunk. It would be touch-and-go. Back to the chart. He plotted it again, then went back to the doc and told him to stall. Give her something to slow the process down. The doc only shrugged and showed his crossed fingers.

As Narwhal passed 1D buoy and swung into the harbor the expectant mother went into labor. The pains were coming at ever-decreasing intervals, doc reported to Cdr. Latta. The OD went ahead full and radio sent a message to have an ambulance meet the boat at the pier.

As numbers one and four were on the capstan and Narwhal was being drawn toward the pier the brow was made ready. The lady was lifted through a hatch and the moment the brow was secured to the pier two strong seamen helped her across and into the ambulance. A 7.5 pound baby boy was born one hour after the arrival of Narwhal. Ben Smith sat in the wardroom staring at the bulkhead contemplating his reprieve. The doc was there also, rolling his bandages and storing his deadly tools. It had been a close call, but for Narwhal, just another routine mission.

On her 9th patrol she evacuated 28 people from Negros Island in February, 1944. On her 10th patrol she repeated the mission, taking another load of 28 people from Butuan Bay. These latter passengers were delivered to the Australian Navy at Fremantle

During September, 1944 Narwhal rescued 31 swimming prisoners of war after Paddle (SS-263) had torpedoed a Japanese prison ship heading for Japan. She brought them safely back to Australia.

On her last patrol, the 15th, Narwhal collected 26 passengers from Negros Island and delivered them to Brisbane.

On January 6, 1945 she had effectively finished her carrier. She departed Brisbane and headed to the Philadelphia Naval Shipyard where she was later stricken from the Navy inventory, and sold for scrap. Here 6 inch guns currently reside at the Submarine Base, New London.