The porthole, a tiny circular window, is used by the ship’s hull for adding lighting and air to the interior of the ship. The function of the porthole is to bring light and air to especially damp parts of the ship located below deck quarters. Just like any window, the port hole window allows the occupants of the lower deck to enjoy a view albeit limited. While air and light can get in, the porthole is water-tight, and can even be light-tight if need be.
Sometimes the porthole of a ship is referred to as the side scuttle, aka side hole. This is the proper term used by the U.S. Code of Federal Regulations, as well as during the construction of a ship. Side scuttle, however, is a broad term that indicated any uncovered hole on a vessels side.
The porthole is made from two structured components, and is very similar to the design of standard windows in both design and application. The porthole is bolted to the ship’s hull carefully and securely. The porthole’s glass may even come in two frames so as to allow the opening and closing of a window. Also, they have storm covers made from metal that work to secure the porthole when heavy seas and storms arise. This is also a way of blocking light if the vessels cargo calls for it. Ship’s used for battle also use storm covers to protect their stealth in battle to avoid enemy detection. These are accessed from the inside of the ship’s hull and are fastened closed by tightening several pivoting devices known as “dogs”.
Portholes that are older typically have a jutting “collar” part of their base plate that is meant to accommodate the thick wooden hull. The size of a porthole can vary. Some may only have diameters of a few inches while others may be a couple of feet wide. This applies to the weight as well, as some may just a few pounds, and others other a hundred pounds! The weight of the porthole is mainly in its glass which can be as thick as two inches. That’s a lot of glass! The metal parts of a porthole also add on to the weight of them. These metal parts are mainly sand-cast and made from bronze, brass, steel, iron, or even aluminium. The most commonly used metals being bronze and brass due to their salt water resistance. The porthole is designed to be secure so as not to limit the integrity of the hull. The porthole’s quality and assured building are what make them so resilient. With anything less, the entire ship would be put into jeopardy.