Not that it matters for the submarine discussion, or maybe this is common knowledge, but here is an abbreviated history of the duct tape allegedly used:
Duct tape, originally not named as such, was developed for sealing ammunition cans as a substitute for paper and wax, which was sometimes difficult to remove. The mother of two servicemen penned a letter to President Roosevelt after her superiors in the company rejected her suggestion, and her proposal was approved. The tape was made of rubberized
duck cloth or duck canvas and for many years was only available in Army olive green. Supposedly, another reason it was called duck tape was because servicemen described its waterproof properties as similar to water shedding off a duck's back.
After World War II, someone got the idea that it would be good for sealing air conditioning ducts, and so now it became known as duct tape. However, a study by a Berkeley Lab (either Lawrence or Livermore) found that it is, in fact, unsuitable for sealing ducts, probably because the adhesive and cloth deteriorate with heat. This was the current state of "duct tape" about 40 years ago.
A common type of duct tape currently sold is silver, with a waterproof coating covering a thin, loose cloth mesh, which seems to be 1/3 or 1/4 the thickness of the original tape. But there are a variety of cloth tapes available that are similar to the original tape.
Military grade duct tape is rated at 50 psi.