The USS Alfr (NCC-1741) was a Constitution-class Federation heavy cruiser starship of the Achernar-subclass, ordered for construction in the 23rd century, named for the star Alfr.

Construction of Alfr was authorized by the Starfleet appropriation of stardate 5930. (TOS reference: Star Fleet Technical Manual)

The stardate given would seem to suggest this ship was ordered during the TAS era. It is not positively known if this vessel was built, only that it was authorized.

Achernar-subclass (Constitution-class mk III class I/class XI cruiser/heavy cruiser starships)
Refit with mk III engines	Bismark • Bonhomme Richard • Challenger • Constellation • Constitution • Defiant • Eagle • El Dorado • Endeavour • Enterprise • Essex • Excalibur • Exeter • Farragut • Hood • Hornet • Intrepid • Kent • Kongo • Lexington • Potemkin • Republic • Saratoga • Valiant II • Yamato • Yorktown
Built to mk III specifications	Achernar • Akagi • Ark Royal • Caspan • Chikuma • Discovery • Forrestal • Kaga • Kitty Hawk • Langley • Littorio • Marseille • Radetsky • Richelieu • Rivoli • Santissima Trinidad • Sirius • Ticonderoga • Victory
Authorized for construction	Ahzdar • Alam'ak • Alferaz • Alfr • Androcus • Annobon • Astrad • Behr'ak • Czar'ak • Ekinus • Elohim • Esabl • Eskiis • Galina • Ghar • Ghondr • Hajj • Hiemdal • Horok • Jassan • Jenshahn • Jupiter • Kars • Kasimar • Kep Salu • Kestral • Ketoi • Maat • Mazda • Mengen • Mirazh • Mondoloy • Mongo • Ndele • Oblik • Oomaru • Paegan • Pari • Pelione • Phardos • Pilar • Procyon • Proxima • Qizan • Qual'at • Quindar • Rigil Kentaurus • Salayna • Samaara • Shaandra • Shahr • Sinuiji • Sol • Tajarhi • Tali • Temir • Thelonii • Tholus • Tulan • Tutakai • Xanthii • Yaan • Za'faran • Zaahm • Zindar