Mobile offshore base

An ocean-wise semi-submersible wave and wind resistant platform capable of moving at one-half the speed of conventional prepositioning monohull cargo ship has been researched and proposed, but never built.

The Mobile offshore base concept emerged during a search for a more cost effective option of sustaining in-theater strike, flight, maintenance, supply and other forward logistics support needs compared with utilizing traditional joint logistics approaches including nuclear-powered aircraft carriers and large medium speed roll-on/roll-off (LMSR) sealift ships.

It was argued, that once positioned, the MOB would operate as a sea base for an extended period, so it would need to have port-like facilities for unloading and loading conventional container and roll-on/roll-off ships.

[5] The joint mobile offshore base (JMOB) was a MOB concept for expeditionary warfare and humanitarian and commercial operations developed in the 1990s by McDermott International, Inc. of Arlington, Virginia.

[6] A technical report presented to the U.S. Congress in April 2000 identified that such a base was technologically feasible and could be built by the defense industry of the United States.

[7][8] However, a 2001 feasibility study for the United States Department of Defense concluded that a MOB would have lower cost effectiveness compared to alternatives such as aircraft carriers and LMSR cargo ships.

[11] In December 1999, the Office of Naval Research (ONR) in response to a congressional mandate issued a report which delineated the impracticality of MOBs, "the largest floating offshore structure ever conceived by maritime engineers",[12] on the grounds of high cost and vulnerability to threats such as missile attack.