Thanks for the reply Don. I actually have that article and it has been invaluable.

My quandry is that some boats had the metal bow and stern sections in whatever upper hull colour they had and others more closely matched to the wood preservative paint. I'm leaning to the latter as I found a photo which is supposedly of U-96 at sea and taken from the bridge which seems to show a lack of any huge tonal difference between the wooden and metal sections.

Looks like charcoal grey it might be!

Cheers,

Tim