Transocean Ltd. (NYSE: RIG) announced on June 4 that John Stobart, executive vice president, COO and chief performance officer, is retiring.

Keelan Adamson, senior vice president of operations, has assumed Stobart’s responsibilities as of June 1, 2018.

“It has been my sincere pleasure to work with John over these past three years,” Jeremy Thigpen, president and CEO, said. “Under John’s leadership, Transocean re-established itself as the standard for excellence, delivering industry-leading performance in safety, uptime and drilling efficiency.”