Answer:
賞 SHOU - prize, praise
勝 SHOU, ka(tsu), masa(ru) - win, be superior
艦 KAN - warship
拡 KAKU - extend, expand
昔 SEKI, SHAKU, mukashi - antiquity, long ago
All take 大 (DAI, oo(kii) - big) in front to make a word, but only 昔 uses the "Oo" reading (OoMukashi); the others are all "Tai/Dai":
大賞 TAISHO - Big prize, Grand Prix
大勝 TAISHO - Great victory
大艦 TAIKAN - Large ship. battleship
拡大 KAKUDAI - Enlargement
大昔 OOMUKASHI - A long time ago