Hatch or door system for securing and sealing openings in marine vessels

A hatch or door system for closing an opening in a surrounding structure, comprising:

• a panel assembly configured to fit within the opening in the surrounding structure in a closed position, the panel assembly comprising an interior panel and a metal frame circumferentially surrounding the interior panel, a latching flange extending outwardly around a substantially continuous perimeter of the frame;
• the panel assembly hinged to the surrounding structure for rotation between the closed position and an open position, wherein in the closed position, the opening in the surrounding structure is closed by the panel;
• and
• an operating mechanism for retaining the panel assembly in the closed position, the operating mechanism comprising a discrete-to-continuous latching mechanism mounted on the surrounding structure and a shaft mechanism mounted on the surrounding structure, the shaft mechanism comprising a plurality of rotatable shafts extending around the perimeter of the frame, and continuous latching elements mounted on the rotatable shafts to contact the latching flange of the frame, the operating mechanism operative in a first stage wherein the shaft mechanism holds the panel assembly in the closed position and in a second stage wherein the discrete-to-continuous latching mechanism seals the frame within the opening.