Abstract: A hydrodynamic swimming mask includes a front mask, including a face lens and a sealing element; and a head strap, such that the sealing element is configured to connect with a skin surface of a face of a user, such that the sealing element and the face lens are configured to form a water tight enclosure that covers the eyes of a user when the user is wearing the hydrodynamic swimming mask, such that the front mask is configured with a shape such that the seal forms a smooth border between the skin surface of the user and the face lens, when the front mask is put on the face of the user, such that there are no depressions, cavities, indentations, or protrusions in the smooth overlap between the face lens and the face of the user, which would cause increased water resistance during swimming.

Abstract: Natural gas deposits vented by oil or gas wells may pressurize a well beyond the capacity of installed apparatus to contain damage in the event of equipment failure, blow-out, or fire with the result that a well may flow out of control. The means and method of this invention provide for emergency action to shear a well casing together with internal piping or tubing and to seal a well if blow-out preventers otherwise provided do not prove effective. The apparatus of this invention may be self-powering.