A tidal stream impeller generator. The generator is a closed container, housing generators and related equipment in a non-flammable environment. The generator housing has affixed to it impeller blades, oriented to maximize the force captured from the movement of seawater with tides at depth. The housing and impeller blades rotate about a conduit, the conduit serving as an axle as well as a conduit for cables, pipes, and related structures to enter the housing without breaching the watertight housing. The conduit passes through end caps on the housing, through watertight bearings.