The ship was powered by four-shaft Westinghouse turbo-electric transmission and eight oil-fired Babcock & Wilcox boilers rated at 26,800 shaft horsepower (20,000 kW), generating a top speed of 21 knots (39 km/h; 24 mph).

[4] The ship was armed with a main battery of twelve 14-inch (356 mm)/50 caliber guns[Note 1] in four, three-gun turrets on the centerline, placed in two superfiring pairs forward and aft of the superstructure.

With her working up now complete, she stopped in New York before steaming south, transiting the Panama Canal, and joining the Battleship Force, Pacific Fleet, in San Pedro, Los Angeles on 17 June.

[10] Fleet Problem XXI, the last iteration of the series, was held in early 1940; afterward, President Franklin D. Roosevelt ordered that the Battle Force transfer its homeport from San Pedro to Pearl Harbor in response to rising tension with Japan over the latter's waging of the Second Sino-Japanese War.

Neither bomb inflicted serious damage, but the ship's magazines were flooded to avoid the risk of the fires raging aboard and around the vessel from spreading to them and igniting the propellant charges stored there.

[5] While en route to the west coast, Pennsylvania left Tennessee and Maryland to head to Mare Island for repairs, while the other two vessels continued on to Puget Sound.

Tennessee slowed, deployed paravanes from her bow to cut the mooring cables for any naval mines that might be in the area, and launched her Vought OS2U Kingfisher scout planes to spot the fall of her shells.

Tennessee, Colorado, and the cruisers Mobile and Louisville steamed into their bombardment positions east of Roi and Namur on 1 February and resumed firing at 07:08 before the marines landed later that morning.

The attack was part of the final phase of Operation Cartwheel, the plan to isolate and neutralize the major Japanese base at Rabaul; while Tennessee's unit raided Kavieng as a diversion, a marine force would land on Emirau.

Shells splashed close to her starboard side and she was straddled several times, forcing her to increase speed to 18 knots (33 km/h; 21 mph) and turning away to open the range, though she was not hit.

Tennessee was detached from the fleet to return to Pearl Harbor by way of Purvis Bay and Efate, arriving there on 16 April for periodic maintenance in anticipation of the next major offensive in the Pacific.

Later in the morning, Tennessee attempted to suppress Japanese artillery batteries on Tinian that engaged the bombardment group and had scored hits on California and the destroyer Braine.

The ship remained on station supporting the marines on Saipan but that afternoon, withdrew to make temporary repairs and protect the troop transports from the expected Japanese counterattack.

[5] Tennessee returned to the invasion beach the next morning to resume providing fire support, which she continued into 17 June, helping to clear the way for American advances and to break up Japanese counter-assaults.

The next major operation would be the reconquest of the Philippines, but to secure the southern flank and capture the Kossol Roads for use as a staging area, the high command decided that the islands of Peleliu and Anguar should be invaded next.

The ship was ordered to destroy a large stone lighthouse to prevent the Japanese from using it as an observation post, but after hitting it three times, it remained standing, and so she shifted fire to other targets.

The American infantry encountered little serious resistance, and the Japanese garrison had been destroyed by 20 September, allowing Tennessee to steam to Kossol Roads, where she replenished fuel and ammunition.

[20][21] Observers aboard Tennessee spotted the flashes in the distance as the light American craft attacked Nishimura's force, and at 03:02, her search radar picked up the enemy ships at a range of 44,000 yd (40,000 m).

[23] In the meantime, the main Japanese fleet, the Central Force under Vice Admiral Takeo Kurita, had passed through the San Bernardino Strait under cover of darkness and arrived early on 25 October.

The Japanese battleships and cruisers attacked Taffy 3, a force of escort carriers and destroyers guarding the invasion fleet in the Battle off Samar, prompting its commander, Rear Admiral Clifton Sprague to make urgent calls for help.

By the time the bombardment group arrived on the scene, Kurita had disengaged, having been convinced by Taffy 3's heavy resistance that he was instead facing the far more powerful Fast Carrier Task Force.

Poor visibility from rain squalls hampered efforts to direct their fire, which began at 07:07 and continued intermittently through the day, as Blandy had ordered his ships to shoot only when their spotter aircraft could observe impacts to avoid wasting ammunition.

Dozens of artillery pieces came out of their protective caves and bunkers to engage the UDTs, forcing them to withdraw while the bombardment group resumed firing on the unmasked guns.

Tennessee and the rest of the bombardment group, reinforced by the fast battleships North Carolina and Washington and three cruisers, opened up with slow and deliberate fire on the landing beaches.

[5] Tennessee operated off the island for the next two weeks, providing fire as requested from the marines ashore and launching star shells at night to help repel Japanese counterattacks.

Fighting raged on Iwo Jima until 26 March, but the fleet needed to begin preparations for the next assault against the island of Okinawa, so Tennessee sailed to the major staging area at Ulithi to replenish ammunition and other supplies.

[5][26] On arriving in Ulithi, Rear Admiral Morton Deyo, the new commander of the bombardment group – which was now designated as Task Force 54 (TF 54) – came aboard Tennessee on 15 March.

Unlike previous assaults, the marines faced no opposition early in the operation; Lieutenant General Mitsuru Ushijima had withdrawn the bulk of his 100,000-strong army to the southern two-thirds of the island, where hilly terrain favored the defense.

On 16 October, she departed for Singapore, where Oldendorf transferred to the cruiser USS Springfield; from there, Tennessee crossed the Indian Ocean, rounded the Cape of Good Hope, and steamed up the Atlantic to the Philadelphia Navy Yard, which she reached on 7 December.

She remained laid up in reserve for twelve years, by which time the Navy decided that she no longer held value as a warship, and so on 1 March 1959, she was stricken from the Naval Vessel Register.