Possible Clues:

• 1944 Hitchcock classic
• Vessel used in rescue
• It carries out rescues at sea, and is carried aboard large ships
• It will come to the rescue, if able to anyhow
• It rescues a lot at sea around first of month
• Iron snake enters illuminated rescue vehicle
• To fable I turn if in danger of sinking
• Somehow fail to be identified as a saver, in the main
• Rescuer, albeit of strays
• Chopped up filet for snaky type inside - it will save someone's bacon if something else is scuppered