The U.S. nuclear weapons tests that were conducted at Bikini Atoll in July 1946 involved two detonations near more than 90 target vessels: one air burst detonation above the fleet (Able) and one underwater detonation (Baker).
After the detonations, personnel worked to decontaminate the radioactive ships (mainly contaminated by the Baker explosion). In August 1946, surviving ships were towed to Kwajalein Atoll so that live ammunition and fuel could be unloaded in uncontaminated water. Work continued through the fall, so my pap would have definitely passed through here during this time.
If you look closely at this picture you’ll notice that these ships appear damaged and somewhat submerged or sinking.