compncards

Hi. Got a question for you folks here. In a recent auction I got what looks like either part of a porthole or a window from a boat. Its brass about 10 inches in diameter, good glass but instead of a door like portholes, it looks like it has threads to screw into something. Is this a part of a porthole or window from a ship? I can take a couple of pics if that would help. Any info would be appreciated.