Abstract: A deep water operations system includes a submersible vessel including a propulsion system for operating the vessel on and beneath the surface of a body of water. The vessel will operate on the water surface to travel to a designated site and then submerge beneath the surface to a depth sufficient to avoid surface wave and weather conditions. A surface power buoy is deployable from the vessel at the water surface and connected to the vessel by an umbilical cord and includes a propulsion system, RF vessel communication and a GPS receiver. An ROV launch cage is supported by the vessel by a second umbilical cord and stores and deploys an ROV remotely controlled from the vessel for deep water work and repair activities via the second umbilical cord.