This post was originally placed against a stamp illustration. Unfortunately I had written up the wrong ship. Out of interest I will leave the write up although I don't think this vessel has been illustrated on a stamp. Thanks to Peter Crichton for pointing out the mistake.
Stalwart Class Ocean Surveillance Ship:
Laid down, 16 April 1984, at Tacoma Boat Building Co., Tacoma, WA.
Launched, 12 January 1985. Delivered to the Navy, 1 May 1985, assigned to the Military Sealift Command (MSC) and placed in service as USNS Assurance (T-AGOS-5)
Placed out of service, date unknown
Laid up in the National Defense Reserve Fleet, Suisun Bay, Benecia, CA. in March 1994
Struck from the Naval Register, 6 January 1995
Transferred, 30 September 1999, under the Security Assistance Program to Portugal, renamed ALM Gago Coutinho (A-523)
Current Disposition, active Portuguese Navy
Specifications:
Displacement 1,565 t.(lt) 2,285 t.(fl)
Length 224'
Beam 43'
Draft 15'
Speed 11 kts.
Complement 18 Civilian 15 Navy
Propulsion Diesel-electric, two shafts, 1,600hp
http://www.navsource.org/archives/09/66/6605.htm