British A.I.O.C. sea going screw steam tug St. Athan stationed at Abadan, Persia in May 1946

Gross register tonnage 427 tons and as dimensions 143.2 (over all) x 30.3½ (extreme beam) x 15.0 (maximum loaded draught) feet. Horsepower 1.250 ihp. Salvage and towing. Part of the fleet of Anglo-Irian Oil Company (A.I.O.C.).(1)

Note
1. According to Lloyds Register 1947-1948 built by Day, Summerc &Co. Ltd,m Southampton, England in November 1919. United Kingdom-flagged, homeport Lonson, official number 143447 and call sign GLBN/ Gross tonnage 427 ton, tonnage under deck 367 ton and as dimensions 135.0 x 29,1 x 13.7 feet.

Source
Quatar Digital Library's digital archive. Naval Intelligence Diversion Admiralty, S.W. 1, Persia Intelligence report May 1946-C.B, 1885 (X) (5/46) Link