I can't find it in American Military Belt Plates, so I don't think it is American military. What made you decide it was silver. Being silver it would likely be fashion related would be my guess.
I believe we have seen similar items here, as well as ones with an anchor but otherwise the same. In a previous thread someone posted a link showing them to be from bathing suits from around the 1920's.
I wish I could get a closer look at the buckle pictured here.... I realize it is an anchor not a sailboat but I would lean more toward the bathing suit connection than anything else.