Captain Blood really re-invigorated the swashbuckler genre. The previous era of swashbucklers had been made in the 1920's when full size ships were more the style than the use of miniatures. In fact this film borrowed some footage from the silent movie Sea Hawk made in 1924. The miniature work is energetic with impressive scenes of splintering hulls and spars, setting the bar for the classic pirate films to follow. Fred Jackman was the special effects supervisor. He was the head of Warner Brothers special effects department but left around this time to start his own independent special effects company.
The three main model ships built for the film were around 18 feet (5.48m) long with 16 foot (4.88m) tall masts. The total cost of building them was $3,300.00.
Other miniatures included mechanised rowing boats and the town under bombardment.
The cannons were electrically fired and made to be clipped into position so that after firing pre-loaded replacements could be quickly fitted for another take.
The miniature crew had a 3 week head start over the live action production to produce the sequences used as background process plates.
Source: American Cinematographer February 1936 - Process Shot Economies made Captain Blood Possible by Fred Jackman A.S.C.