Patent ID: 8875805

Claim:
A mobile drilling system comprising: a top member having a drilling rig positioned thereon; wherein said top member is floatable in order to be transported to different drilling sites and is removably engageable with a tower member located on a base member of a foundation member; wherein said tower member has a portion extending above an expected ice level; wherein the foundation member is ballastable and deballastable, so that it can be floated to an installation site, said top member having jack up legs for elevating and lowering the top member out of and in to water; wherein the top member comprises a recess formed in a side of the top member, the recess receives and partially surrounds a circumference of the tower member; and wherein said top member is adapted to be locked on top of said tower member so that the jack up legs can be lifted out of the water after the top member has been engaged with the tower member.