Offshore drilling, simply put, is the process of exploiting mineral resources in the seabed; most of those resources are related to the oil and gas industries. Drilling is conducted by several kinds of specialized vessels, some with a planing hull supporting huge legs and a drilling platform, some with legs more than 300 feet long that rest on the seabed to support a drilling platform, and some that are ships, either purpose-built or converted from other forms of commercial vessel, with a drilling rig on top.