The Curnow class tactical cruiser was a type of Federation starship on active duty during at least the late 23rd century. Construction of the class was authorized in December, 2287 and the first ships of the class were commissioned probably ca. 2289 or 2290. (Jackill's Starfleet Reference Manual: Ships of the Fleet, vol. 3) The secondary hull was similar to that of the upgraded Excelsior-class, with hull reinforcements on either side of the navigational deflector. (Jackill's Starfleet Reference Manual: Ships of the Fleet, vol. 3)