The Special effects were supervised by Byron Haskin and photographed H. F. (Fred) Koenekamp.
Byron Haskin described Fred Koenekamp as "the greatest trick man who ever lived." Haskin also said that each miniature ship, built to 1/12th scale, concealed an operator who, from a prone position would guide the rudder and work the little inboard motors and the tiny Cannons.
I assume the little inboard motors would be referring to the motorised rowing mechanism of the Spanish Galley. The models were generally towed through the water by an underwater cable.
The ships were shot on the Warner Brothers backlot lake with the cameras mounted low in glass fronted boxes and shooting at around 70 frames per second. The bow waves were enhanced by a underwater nozzle pumping water up at an angle.
The models are very finely detailed with particularly good looking sails, and the camera gets pretty close in some shots.
A section of the black and white film, namely when the story moves to Panama, was tinted a sepia colour. It was supposed to represent the unrelenting heat and humidity of the place as experienced by the characters.
|Note bendy rubber armed miniature figure posed atop the yard.
American Cinematographer Magazine August 1996, Part 2 of a Sea hawk article by Rudi Behlmer.
A directors Guild of America Oral History - Byron Haskin Interviewed by Joe Adamson, published by the Scarecrow Press 1984.