https://patents.google.com/patent/DE2625520A1/en

In the oil drilling industry, certain devices are used for drilling Oil drilling used in underwater areas. In general, these arrangements have a riser consisting of individual There are sections that stretch from a floating watercraft on the surface all the way down to the underwater one Extend borehole. On the watercraft, the upper part of the riser protrudes through a through-hole in a turntable, the subsequently

vessel encompasses a wide variety of ships, boats, craft, etc.