From ICG Magazine, Watership Down by Pauline Rogers (May 2000)
All submarine interiors-- both American S-boats and German U-boats-- were photographed on sets constructed on Soundstage Five at the reputed Cinecitta studios in Rome, Italy. "We divided the first-unit shots up into sections," divulges Wood. "We had a sub on set at Cinecitta, created 20 percent bigger than normal size, which didn't feel any bigger, since we still had to stoop to get through the doors. Because it was going to be filled with water most of the time, we had to go 110-volt DC [in terms of electricity]. To light it, we cut hundreds of holes over the top to focus tiny little [150-watt] Pepper lights inside. The biggest light on this set was a 300-watt bulb. There was nowhere to hang the lights.
"We took the studs out of some of the loud speakers and put magnets in, so we could stick the lights to the metal. That worked fine, when we were level. However, when the set 'shook' they would fall out. So we tried finding ways to screw things in. Whenever we saw a light in the frame, we struck a bit of black in front of it. Simple, but it worked. I really think this picture was made with Black Wrap. It was an integral part of lighting this whole project!"