The United States Postal Service is honoring the U.S. Merchant Marine by releasing four stamps on 28th July, 2011 featuring vessels playing an important role in U.S. maritime history, including a Matson Navigation container ship. The Matson ship is based on an undated photograph of the R.J. Pfeiffer, which was launched in 1992, and is depicted passing Diamond Head in Honolulu, Hawaii. The container ship illustration is meant to represent the container ship era in America’s maritime history, and how without them the global economy as we know it would not be possible.In addition to the R.J. Pfeiffer stamp, the new series includes images of a clipper ship, auxiliary steamship and Liberty ship.The Merchant Marine stamp series are being issued as “Forever” stamps, meaning that they will always be equal in value to the current first-class, 1oz. mail rate.