August 1944–January 1945

Following shakedown training off the coast of New England and in Narragansett Bay, Blower departed Naval Submarine Base New London in Groton on 17 September 1944 for advanced training at the Sound School in Key West, Florida. She left Key West on 10 October 1944 bound for the Panama Canal and the Pacific Ocean. Early on the morning of 11 October, during a heavy rain squall, the submarine chaser USS PC-1145 collided with her. No one on either ship suffered any injuries, but PC-1145′s bow was smashed back to the first water-tight bulkhead. Blower suffered a hole in her bow buoyancy tank, damage to her conning tower, and a sheared blade on her starboard propeller. She returned to Key West on 12 October 1944 for repairs, but the damage proved to be so extensive that the work had to be completed at Groton.

Blower got underway from Groton again on 13 November 1944, bound via the Panama Canal for Pearl Harbor, Hawaii, which she reached on 16 December 1944. She spent a month training at Pearl Harbor, then proceeded to Saipan in the Mariana Islands, where she topped off her fuel supply.

First war patrol

Blower departed Saipan for her first war patrol on 17 January 1945. She spent most of the 48-day patrol in the South China Sea between Hainan Island and Japanese-occupied French Indochina off Cape Tourane. She served as part of a scouting line of 15 submarines stretched out across the South China Sea between Singapore and the Formosa Strait along the most probable track for Japanese warships returning to Japan after an oil resupply mission to Singapore. On 13 February 1945 she sighted the masts of a battleship and two cruisers and, after some maneuvering, managed to fire six torpedoes from a range of 1,800 yards (1,600 m). Her sound operators reported one hit on each of two targets, and she later spotted two oil slicks, but Japanese records do not indicate any damage. She also tried to attack Japanese convoys off Tourane, French Indochina, on 15, 22, and 24 February 1945 but could not get close enough, mainly owing to Japanese air patrols and large numbers of small fishing boats that impeded her efforts. Groups of floating mines often forced her to submerge at inopportune moments, further disrupting her operations.

With her diesel fuel running low, Blower headed for Fremantle, Australia, on 5 March. She arrived at Fremantle on 19 March 1945 and began a refit alongside the submarine tender USS Euryale (AS-22), during which she received new LORAN (long-range navigation) and radio direction-finding equipment and an overhaul of both of her radars and all four of her diesel engines.

Second war patrol

Blower departed Fremantle to begin her second war patrol on 14 April 1945. After a brief stop to refuel at Exmouth Gulf on the coast of Western Australia, she proceeded through Lombok Strait on 21 April 1945 and took up a patrol station in the Java Sea. On 22 April, she received orders to form a coordinated attack group with the submarines USS Besugo (SS-321) and USS Perch (SS-313). The three submarines set up a scouting line at 20-nautical-mile (37 km; 23 mi) intervals across the east-west shipping routes between Makassar and Borneo and covering the north-south lanes between Borneo and Java. Blower′s only surface contact was with Besugo, with which she rendezvoused twice. Blower also was plagued by numerous Japanese patrol aircraft. Indeed, at 11:30 on 25 April 1944, her lookouts spotted two closing Imperial Japanese Navy floatplanes and she quickly dove to avoid attack. Unfortunately for Blower, the water near Solombol Island was clear and only 150 feet (46 m) deep, allowing the floatplanes to bomb and otherwise harass her for almost two hours as she twisted and turned along the sea bed.

Early on the morning of 26 April 1945, Blower picked up two slow-moving radar contacts at a range of about 15,000 yards (13,700 m). Concluding they were what the Americans called "sea trucks," a type of slow Japanese cargo ferry, Blower closed to engage them on the surface. At 03:22, however, one target turned and increased speed to 19 knots (35 km/h; 22 mph), indicating that she was a warship rather than a "sea truck" and prompting Blower to start bearing away. Ten minutes later, at a range of 12,750 yards (11,660 m), the Japanese ship opened fire with a three-gun salvo, bracketing Blower, with two shots landing within 75 yards (69 m) of her. Blower′s war diarist later noted "On target - this boy had nice radar ranges. Submerged." Blower then maneuvered to try and launch a submerged attack, but the Japanese warship moved in a fast search pattern until heading off to the northwest toward Perch′s position at 05:30. Just over 12 hours later, Blower rendezvoused with Perch, whose commanding officer, Commander Francis B. McCall, said the Japanese warship "had worked him over plenty about noon and put his radar and attack periscope out of commission."

Moving to a nearby patrol position on 27 April 1945, the coordinated attack group cruised off southern Borneo for over a week. It did not find any worthwhile targets, just the ever-present fleets of small native sailboats. At one point, Blower′s diarist wrote "Sailboat in sight. They are even up here. Would certainly like to practice [on them] with the 40 mm's [i.e., Blower′s 40-millimeter guns]."

Turning northwest on 6 May 1945, Blower proceeded to Cape Varella off the Malay Peninsula, arranging for a rendezvous with the submarine USS Baya (SS-318) at 12:30 on 9 May, just after exchanging calls with Perch. The entry in Blower′s war diary reads: "Received mail from Baya. What a commentary on the vaunted Jap[anese] air power in the South China Sea. Three fleet submarines within five miles [i.e., 5 nautical miles (9.3 km; 5.8 mi)] of each other; two exchanging mail and movies, and one proceeding unconcernedly on its way." Targets were no more apparent in her new patrol area than off Borneo, however, and Blower turned to providing lifeguard duties for United States Army Air Forces B-29 Superfortress four-engine bomber strikes on Nha Trang and Saigon in French Indochina on 12 and 21 May 1945. She also conducted a submerged reconnaissance of Vân Phong Bay and Nha Trang Bay on 16 May but saw nothing other than local fishing sailboats. Perhaps the most exciting moment took place on 19 May, when Blower′s crew exchanged recognition signals by flashing light with a B-24 Liberator four-engine search plane which passed 50 feet (15 m) overhead, an event commemorated by the war diary entry "They are damn big and look bigger when they are headed in on you."

Blower headed for the Philippine Islands on 23 May 1945, completing her patrol when she moored alongside the submarine tender USS Anthedon (AS-24) in Subic Bay on the coast of Luzon on 24 May 1945.

Third war patrol

Following a two-week refit, Blower, now under the command of Lieutenant Commander Nelson P. Watkins, departed Subic Bay on 23 June 1945 to begin her third war patrol, bound for a patrol area in the Gulf of Siam She sighted Tenggol Island off the east coast of the Malay Peninsula on 28 June 1945 and began patrol operations there. She made rendezvous with the submarine USS Bluefish (SS-222) on the night of 30 June 1945, and the two submarines agreed to coordinate their patrol coverage. Taking the area south of the island, Blower sighted an empty lifeboat on the morning of 1 July, sparking an impromptu target practice with the aft 40-millimeter gun. The crew fired eleven rounds, getting one hit at a range of 1,000 to 1,500 yards (910 to 1,370 m), a result memorialized in the war diary as "The practice was justified by the caliber of the shooting. Terrible." Blower then moved "close aboard and let Gunnery Officer have a go at it with grenades. Result - sore arm. No damages. All in all a very sorry exhibition, so secured, leaving lifeboat bloody and sinking."

On 4 July 1945, the two submarines rendezvoused again to lay out a plan to investigate a ship sighting reported by patrol aircraft. Unfortunately, according to Blower′s war diarist, the aviators' plot "of position showed ships anchored in the mountains." Just in case, the two submarines approached the coast of Japanese-occupied British Malaya and, as Blower′s war diarist reported laconically, "had a good look at all possible anchorages and inasmuch as no ships were sighted zoomie [slang for "aviator"] position must have been correct." Later that day three of Blower′s lookouts spotted a periscope at a range of 800 yards (730 m) and closing. Blower′s war diarist later noted the crew were surprised no attack came as Blower dived to escape and wondered if their would-be assailant was friendly. The next day, the British submarine HMS Sleuth reported attacking a large Japanese submarine with no results, suggesting Blower had indeed made a lucky escape.

On the evening of 9 July 1945, after Blower rendezvoused with Bluefish, the two submarines followed, then closed to attack two Japanese submarine chasers off the Malay coast. Bluefish sank one of them, but Blower broke off her attack run when the other submarine chaser turned away. The two submarines surfaced to try a gunnery attack, but the surviving submarine chaser fled into a minefield and escaped.

On 11 July 1945, Blower tried another night attack, this time against a medium-sized vessel she identified as either a cargo ship or an escort ship. She fired three torpedoes at a range of 3,500 yards (3,200 m). Unfortunately, the first two torpedoes, according to Blower′s war diarist, "leapt clear of the water and chased each other off in a direction not that of the target." The third torpedo missed ahead.

Standing eastward the following day to join a coordinated attack group led by the commanding officer of the submarine USS Charr (SS-328), Blower began patrolling near the Natuna Islands. On 15 July 1945, after tracking the Japanese submarine I-351 in the early hours of the morning, Blower fired four torpedoes at the zigzagging submarine from a range of 1,000 yards (910 m). Instead of the expected "blinding flash" though, Blower′s war diarist wrote that ′the crew heard "only a sickly thump followed shortly after by another thump, both loud enough to be heard throughout the boat. The first two had hit - duds." After a short drop down to avoid any torpedoes fired back down her torpedo track, Blower started up to fire her stern torpedo tubes but was shaken by three nearby explosions. Her sound operators reported fast screws nearby and, worried that a Japanese escort had shown up, stayed low until the presumed Japanese escort ship had moved off. Although unsure of what had happened, Blower radioed a contact report, and an hour later was rewarded by a terrific explosion over the horizon. This was followed shortly thereafter by a report from Bluefish that she had sunk I-351.

Following this encounter, Blower shifted to the Java Sea near Batavia, but encountered only sailboats. Those contacts proved nerve-wracking nonetheless, as constant night radar contacts and poor visilibilty produced several near collisions. To make matters worse, Blower had at least one encounter with two unidentified Allied submarines, avoiding a friendly-fire incident when she flashed a recognition signal to them. Seeing that the area was overly crowded, Blower passed south through the Sunda Strait to patrol in the Indian Ocean off the south coast of Java. At 13:45, the executive officer remarked "Well, the only thing we need to make the patrol complete is to get bombed." Fifteen minutes later, lookouts spotted an Imperial Japanese Navy Mitsubishi G4M bomber (Allied reporting name "Betty") that dropped two bombs near Blower.

With no targets in sight and low on fuel, Blower headed east and arrived in Fremantle, Australia, on 28 July 1945, completing her patrol. She was still at Fremantle when hostilities with Japan ended on 15 August 1945, bringing World War II to a close.