Hood's possible gray antifouling paint

Could HMS Hood's underwater hull have used gray rather than red antifouling paint in 1941?

Yes; gray antifouling paint existed, and wartime dockyards could use the suitable coating they had available.

Research cited by a viewer suggests that Hood carried gray rather than red antifouling paint in 1941. That is plausible because gray antifouling coatings existed. In wartime, a dockyard could use whichever suitable stock was available instead of preserving a familiar peacetime color convention. The paint question therefore opens onto the practical limits of maintenance supply.