Shadow Killers Tiger Force (1986)

This is one of the earlier cut-and-paste ninja films of Godfrey Ho, using only one old film - and a women's prison film at that - and new footage with ninjas. Ninjas kidnap women and take them to a camp as slave labor in a secret lair no one can find, but still manages to have mail call. A female ninja comes to rescue one of the women before she and 52 others are sold to the Middle East. There's a torpedo, a beheading by belt, a telekinetic ninja using sign language because she's talking to a woman from a different film (and one is indoors and one is not) and, after a lot of tedium, a finale involving a ninja-seeking rocket.