1869 SS Adriatic 12c Green
This pictorial shows the SS Adriatic. I do not own this stamp yet. It is here courtesy of the Wikimedia Commons.
Ships
1893 Columbian Exposition: Santa Maria 3c Green
This stamp commemorates Columbus by showing a likeness of his flagship, the Santa Maria. Note: I do not own this stamp yet. It is here courtesy of the Wikimedia Commons.
Steamship 10c Carmine Rose
This parcel post stamp shows a steamship and mail tender, presumably hauling parcels.
2012 USS Constitution (Forever) Multicolored
This stamp commemorates the 200th anniversary of the War of 1812 by showing the USS Constitution.
1997 Pacific 97 32c
This pane of stamps shows ships and stagecoaches. It was issued for the 1997 Pacific International Stamp Exhibition.