The ship on the stamp is incorrectly
dentified as "HMS Gordon 1864." The correct identification is "Royal
Navy Sail Sloop 1864" according to Jean-Pierre Mangin (Guide
MOndial des Timbres Erronés, vol. 2, Yvert & Tellier, 2005).
It also appears that the flag at the stern of the ship is flying in
the wrong direction. A sailing ship is propelled by the wide blowing
from the stern, so the flag should be flying toward the bow.