Sutho wrote:
Pretty sure in "Alarm Starboard" by Geoffrey Brooke he describes seeing the Ark Royal pitching at sea from the Nelson and wrote that her underwater hull looked to be a brown colour.
Not the hull, just the forefoot as I read it:
(Page 7) “…heaving her bow right out of the sea so that the angular brown-painted forefoot jutted clear…..”
Brooke records the incident with Ark Royal as being two weeks into the war, so roughly mid September 1939. Her previous docking was July 1939 and the relevant D495 docking report tells us that at that time Ark Royal’s bottom was coated with Moravia paints, but this particular report does not tell us the colour of the paints used.
First on would have been two coats of protective. Moravia protective came in grey and red. Say the grey went on first and red second. We don’t know the hue of Moravia ‘red’ but my suspicion, based on the builder’s model of KGV, is that Moravia’s red protective was actually quite brown.
After that came the top coat, the anti-fouling. Moravia anti fouling came in grey or black. The bow area was one of the areas of the bottom subject to most wear from water friction, the forefoot perhaps particularly so. Say the anti fouling there was beginning to wear off and the top layer of protective was showing through…. that could account for what Brooke recalled when he wrote his book 43 years later.