Abstract: An underwater air pocket work unit has a work chamber contained within a double walled flotation chamber, the upper end of which has a resilient gasket to seal against the hull of a vessel, or other submerged structure. The work chamber is open completely through the structure to provide unobstructed access at both ends and the flotation chamber is open at the lower end. Valves are provided for admitting pressurized air to the flotation chamber to control the buoyancy for holding the structure in place, and for admitting air to the work chamber as necessary for working space. Both chambers have dump valves for releasing the air and the work chamber has window ports for holding work lights.