I heard that the name "100MPH tape" was granted by Alaskans who taped their cars together and found that it was good up to about 100mph. Or so say my Alaskan buddies.
Great stuff, duct tape. My brother-in-law duct taped the internals of his old upright piano together. It was a little hard to tune, and some of the keys were a little sticky, but otherwise good to go.
In the submarine force, we have a stuff called "EB Green," popular in the shipyard of Electric Boat. It's like duct tape on steroids, heavier and with a stronger adhesive. There are stories about components in sea-water systems that have inadvertently been taken to test depth (the deepest the boat is designed to go) and have survived.