A mother ship, mothership or mother-ship is a large vehicle that leads, serves, or carries other smaller vehicles. A mother ship may be a maritime ship, aircraft, or spacecraft.
Examples include bombers converted to carry experimental aircraft to altitudes where they can conduct their research (such as the B-52 carrying the X-15), or ships that carry small submarines to an area of ocean to be explored (such as the Atlantis II carrying the Alvin).
A mother ship may also be used to recover smaller craft, or go its own way after releasing them.
A smaller vessel serving or caring for larger craft is usually called a tender.
The term mother ship dates back to the 19th-century whaling trade when small, fast ships were used to chase and kill whales. The dead meat from several boats was then brought back to the larger, slower ship for processing and storage until the return to land. This model enabled a far more efficient method of whaling. Though whaling is much lower-scale than in earlier days, the single large storage ship model is still used extensively by fishermen. Such ships are known today as factory ships.
In many languages, such as Chinese, Finnish and Japanese, the word mother ship refers to an aircraft carrier; see (literally "mother" + "warship").
During World War II, the German Type XIV submarine or Milchkuh (Milk cow) was a type of large submarine used to resupply the U-boats.
Mother ships can carry small submersibles and submarines to an area of ocean to be explored (such as the Atlantis II carrying the Alvin).