||Portholes seal up tightly against the elements and don't allow water in while allowing light to come into a cabin and air to circulate if opened . They are essential to any ship or boat.
When the seas are high and waves are crashing against the hull they can be dogged down tight to keep the sea out.
We carry portholes in many sizes. Some are brightly polished brass, some are carefree aluminum. All of our portholes can be converted from mirror to window glass .