The Joint Mobile Offshore Base (JMOB) will enhance the ability of the United States to provide logistical support for the projection of power and aid worldwide. At the same time, it will lend greater security to the men and women on it. And compared with traditional land bases, this moveable, reusable investment is not subject to the politics of other nations, enabling military equipment to be pre-positioned in the theater of interest within 30 days nearly anywhere in the world.

McDermott performed an extensive evaluation of the JMOB concept for the Naval Surface Warfare Center under sponsorship by the Defense Advanced Research Projects Agency (DARPA) and Office of Naval Research (ONR) using offshore oil production and construction technology. Hydrodynamic tests of a 1/60-scale model were completed to confirm naval architecture and motion calculations for a variety of sea states. These tests verified the feasibility of design methods. The conceptual design has been model tested for validity as well as verifying the unit’s performance through analytical and simulation methods.

In transit, each vessel will be able to operate independently, deballasted onto its ship-shaped lower hulls for propulsion efficiency. On reaching an operational theater, the units can be ballasted to a deeper draft, submerging the lower hulls so that only the columns, supporting the upper hull, are exposed to the sea. This greatly reduces the motion of each module. The modules will then be connected at the upper hull to form a full JMOB unit and to allow some relative motion between units. The individual modules are substantially identical. All have power generation, propulsion, control, cargo handling, and air traffic control systems and are capable of completely independent operation. This multiple system redundancy allows military operations to begin with one module on station and permits smaller operations to be performed with less than a full JMOB. Five individual single-base units, each 1,000 feet long, connected together can form a one-mile floating runway 500 feet wide and 120 feet above the ocean surface.