During filming, a near-serious accident was averted. When Jake (Richard Rossi) was about to grab the large chest as the crane lifted it from the and swung it towards him, the crane slipped and it came perilously close to clocking him in the head at a rapid speed. Fortunately, he ducked and they were able to re-shoot the scene.
The fictional submarine here is USS Dolphin. Two US submarines have borne that name - SS-169 and AGSS-555. The first one, SS-169, was a V boat, which served 1932-45; she was at Pearl Harbor during the attack on 07 December 1941, and she left on her first war patrol on 24 December 1941. The second Dolphin, AGSS-555, was a small deep-diving R+D submarine, which served 1968-2007.
Despite the switch in Season 5 from "Full Screen" (4:3 aspect) to "Wide Screen" (16:9 aspect), a brief flashback scene at the beginning of the episode was deliberately filmed in 4:3 Full Screen. This was presumedly to remind viewers that the event occurred in the past at a time when TV would have been Full Screen.
In the American submarine's contact report, there is reference to cruisers, battleships, and "flattops" in the Japanese fleet as it approached Pearl Harbor on December 5. In the real world, the slang term "flattop" is credited to Lieutenant Commander Robert Dixon, who radioed "Scratch one flattop!" to report the first sinking of a Japanese aircraft carrier. This happened during the Battle of the Coral Sea in May of 1942, five months after the Pearl Harbor attack.
While Robert's advises Campbell he could have a heart attack exercising so hard in a rubber suit, Campbell is, in fact, wearing an exercise suit made of plastic that rustles as he walks.