***Minor Plot Spoilers***
I must confess to having a soft spot for Wayne Crawford. I know little about him, but he appears to have masses of enthusiasm to compensate for his lack of talent. In his films he usually performs multi-tasks - perm any 3 from lead male, director, producer and script-writer - tackling story lines from the sub-basement. Despite this the end product is usually enjoyable fun for the non-discerning.
'The Evil Below' features Crawford as a down-on-his-luck Captain of a ramshackle charter boat, a bit like Bogart in 'To Have & Have Not' - the similarities between the films ends here though.
The story begins with an underwater scene with two divers searching a wreck, before being attacked by an unseen creature - bit like the start of 'Jaws 2'. The wreck turns out to be that of the 'El Diablo', which went down centuries earlier. The ship was manned by heretic priests on the run from Spain, with a cargo of stolen Church treasure. This allows the introduction of various links to supernatural forces with Lucifer and The Armageddon both getting a look in. The films title refers to this sunken Devil-ship, rather than any malevolent sea-creature.
Whatever faults the film has (and there are many) it is fun to watch and competently made. You can't help but like a film which, in the final 5 minutes, copies the famous beach scene in 'From Here to Eternity' and the final line from 'Casablanca'.