Vantage Drilling Co. reports that the terms of the Cobalt Explorer construction contract have been amended to defer the second progress payment on the newbuild ultra-deepwater drillship until July 2015.

In consideration of the deferral, Vantage says it has also agreed to reduce the potential liquidated damages associated with the contract. All other terms and conditions of the construction contract remain in full force and effect.

The Cayman Islands-exempted offshore driller has a fleet including three existing ultra-deepwater drillships, the Platinum Explorer, Titanium Explorer and Tungsten Explorer, as well as the additional ultra-deep DP drillship, Cobalt Explorer, currently under construction.