While both this photo, and the previous photo, were taken on my workbench the plywood is representative of the hull of your boat and the bronze fittings of two very typical installation methods used today. In this photo one can easily see the major differences in how both of these installations are affixed to the hull.
This photo is representative of a proper seacock installation with a through-bolted flange and the previous photo of a not-so-good installation method with no flange and mismatched threads.