Spanish television station RTVE has posted video footage from the set, featuring some of the shooting and a brief interview with Balagueró and Manuela Velasco, who plays Vidal. It is in Spanish without subtitles, but Balagueró discusses the complexities of filming on the boat, and his attempts to create the claustraphobic atmosphere of such a space.
Considering that the film series began as almost a lark as a small film project between friends more than six years ago, it's amazing to see how far it's come, and how the series has altered the course of the found footage mode. The film is due to be released next year.