Sighting a red smoke bomb and a rescue buoy from Squalus, she established communications, first by underwater telephone and then by signals tapped in Morse code on the hull.

Sculpin aided in the salvage of the sunken vessel by sounding out the approaches to Portsmouth, New Hampshire and preparing supplementary charts of the area where Squalus was refloated.

Departing Cavite on the night of 8–9 December 1941, Sculpin – commanded by Lucius H. Chappell – Seawolf escorted Langley and Pecos as far as San Bernardino Strait.

After Tarpon was twice "pooped" by heavy seas, Sculpin requested she be moved back to Lamon Bay, where she found weather so bad, she proved unable to attack Japanese shipping going in or out.

Three nights later, Sculpin detected a Japanese task force (bound for Makassar City, Celebes)[8] made up of destroyers, cruisers, and an aircraft carrier[8] (a startling sight, as it remained for the duration).

[8] On the night of 17 February, she was detected while making a surface attack, firing two torpedoes each at a freighter and a destroyer, all of which missed,[9] and she was forced to dive.

Off Cape Varella, Indochina, early on the morning of 19 June, she torpedoed a cargo ship, making a hit forward of the stack.

A heavy secondary explosion was heard, and the damaged vessel was last seen headed for the shore to beach, smoke pouring from her forward hatch.

She moved to Brisbane, under Ralph Waldo Christie (part of Admiral Arthur S. Carpender's 7th Fleet, and ultimately General Douglas MacArthur's South West Pacific Area command), along with the rest of Submarine Squadron Two (SubRon 2), in August.

Escaping the Japanese escorts' countermeasures, she remained in the general area where, a week later, she intercepted a three-ship convoy in the shipping lane between Rabaul and Kavieng.

Waiting until the escorting destroyer had made a patrol sweep to the opposite side of the convoy, Sculpin fired a spread of four torpedoes at Sumoyoshi Maru.

[14] Departing Brisbane on her sixth war patrol, from 18 November 1942 – 8 January 1943, Sculpin worked her way past New Britain to the rich hunting grounds off Truk.

[16] Sculpin arrived at Pearl Harbor on 8 January 1943, and sailed east to San Francisco, California, spending three months in overhaul at Mare Island.

Around midnight on 9 June,[17] three days after arriving on station off Sofu Gan (also called Lot's Wife),[18] she detected a Japanese task force consisting of two aircraft carriers with a cruiser escort.

On 14 June, she damaged a cargo ship but was forced to dive and run silent to avoid the vigorous countermeasures of the maru's escorts.

[19] Sculpin's eighth war patrol, from 25 July–17 September, was off the Chinese coast, in the East China Sea and Formosa Strait.

On 21 August, she intercepted an armed cargo ship and fired a spread of three torpedoes which ran "hot, straight, and normal" but did not explode.

Following a brief overhaul period at Pearl Harbor, Sculpin – commanded by Fred Connaway – departed Hawaii on 5 November 1943.

The account of Sculpin's final patrol was given by the surviving members of her crew, who were liberated from Japanese prisoner of war camps after V-J Day.

Making a fast end run on the surface to attack on the morning of 19 November, she was in firing position but was forced to dive when the convoy and its escorts zigged toward her.

When the Japanese task force changed course, Sculpin surfaced to make another run, but was discovered by Yamagumo,[20] which the convoy commander had left behind for just this eventuality,[20] only 600 yards (550 m) away.

Fearing he might reveal the plans for the Tarawa invasion under the influence of torture or drugs, Cromwell refused to leave the stricken submarine, giving his life to escape capture.

Sculpin's diving officer, Ensign W. M. Fiedler (who failed to notice the depth gauge had stuck), along with ten others, some doubtless already dead, joined him.

The survivors were questioned for about ten days at the Japanese naval base at Truk, then were embarked on two aircraft carriers returning to Japan.

On 4 December, the carrier was torpedoed and sunk by Sailfish and twenty of the American prisoners perished; one man, George Rocek, was saved when he was able to grab hold of a ladder on the side of a passing Japanese destroyer and hauled himself on board.