It was early June 1942. Dal and I were analysing the breakdown of the shooting script. We were surprised to discover that the lifeboat carried the largest number of scenes. As no one had ever attempted to shoot sustained synchronous dialogue scenes in an open ship's lifeboat, at sea, supposedly in mid-Atlantic, obviously they were going to present problems. As we would be breaking new ground, many would be unforeseen and would have to be resolved, hopefully, as and when they appeared. It would need Merlin to foresee them all and take the necessary measures to avoid them.

The lifeboat must carry a cast of about 24, the camera crew of two if not three, the ‘mike’ boy, someone to hold the reflector, the continuity girl, and me. Thirty-six people. Then, there was the equipment. The Technicolor three-strip camera which was as cumbersome as the average sized refrigerator. To mount it was going to be difficult in a lifeboat, bouncing about in seas that were supposed to be in mid-Atlantic. The normal tripod could not be expected to keep on its feet against every angle of pitch and corkscrew roll that the boat would obviously undergo. We would have to have an adequate towing craft which must house the sound equipment because we couldn't expect the lifeboat to take the recordist and his paraphernalia. Besides, we must be free, so far as possible, to be able to move around to alter the camera set-up after each shot. Our towing craft therefore would have three cables pulling us through the water: the microphone cable, the camera cable and the main towing cable. Quite a prospect, obviously fraught with imponderables. I asked Dal whether Technicolor had ever put to sea in a lifeboat with their three-strip and recorded sound.

‘They've made a film called Western Isle, but whether they recorded sound we'll find out.’

‘With a blimped camera and no post-synching back in the studio. Direct sound, that's the key question.’ Dal was soon on the phone to Technicolor, on the Bath Road, opposite open farm lands where already bulldozers were at work on Heathrow. He asked for George Gunn, their brilliant head technician and inventor.