Death Star
The Death Star is a type of fictional mobile space station and galactic superweapon featured in the "Star Wars" space opera franchise. The first Death Star is stated to be more than 100 km to 160 km in diameter, depending on source. It is crewed by an estimated 1.7 million military personnel and 400,000 droids. The second Death Star is significantly larger, between 160 km to 900 km in diameter depending on source, and technologically more powerful than its predecessor. Both versions of these moon-sized fortresses are designed for massive power-projection capabilities, capable of destroying multiple naval fleets or entire planets with one blast from their superlasers.
Jackass-barque
A well-known example of a steel four-masted jackass-barque was the "California" (1890), the last and largest of the White Star sailing ships. The use of steel enabled the addition of another hundred feet to the two hundred foot effective maximum length of a wooden vessel. A fourth mast, called the jigger, provided the driving power for the increased length. The lower and topmast were built in one steel tubular piece. Mechanical improvements were introduced to the rigging.