Pressure Type for Marine Porthole

According to the structure type of the boat, the pressure of porthole is divided into three types, one is A-type heavy porthole, the second is B-type medium porthole, and the third is C-type light porthole.

The structure of the heavy-duty and medium-sized portholes is similar. The main difference is the thickness of the glass. When the porthole is opened, it is divided into left-opening, rear-opening, co-hinged and fixed. When the window is short, a circle of flanges should be set for installation and fixation. If the window is long, it can be welded directly to the ship.

Heavy-duty are generally installed below the bulkhead deck or freeboard deck of sea-going ships, where the side openings are allowed above the full load waterline, and where watertight and airtight are required.

Medium-sized portholes are installed on the end of the side or superstructure above the bulkhead deck or freeboard deck in passenger ships, on both sides and ends of the first superstructure on the freeboard deck in non-passenger ships.

Light type are installed above freeboard for passenger vessels