H.L. "Duke" Zinkgraf
prolific inventor, Duke Zinkgraf provided practical solutions to the
problems of dynamic positioning (DP) of offshore rigs, including the
world's first DP coring vessel, the Eureka. He was intimately involved
in the design and construction of the SEDCO 445, the world's first DP
vessel used to drill exploratory wells with a riser and subsea BOP. He
was also actively involved in building the SEDCO 709, the world's first
DP semi-submersible rig.
Working for The Baylor Company, Zinkgraf
was instrumental in adapting the eddy current current brake to the
drilling industry, and was the first to convert rig power from AC to DC to
provide higher efficiency. He also assisted Varco with the design of the
top drive system.