Information for this article came from a British Admiralty publication, C.B. 3098 (45) R, entitled The Camouflage of Ships at Sea. A Xeroxed copy of the document was given to me by John Lambert, noted Naval Historian and co-author of the series of books called Allied Coastal Forces.
Since the date printed on the document was October 1945, I can only surmise that the descriptions of the two schemes designated for what the document refers to as "Coastal Forces Boats" are for the later stages of the Second World War.
The Royal Navy had two schemes for these boats, Scheme E (for boats operating in Home Waters) and Scheme F (for boats operating in Foreign Waters).
"Scheme E is the light modification of the basic design for Coastal Force craft and is for use on Home stations only. The colours used are G.45 and White on vertical surfaces and B.15 on horizontal surfaces, with full countershading in White and colour B.15. It is of particular importance that the countershading in Schemes E and F should be executed with great thoroughness, since at the very short ranges at which actions between coastal forces are fought and at which concealment of small craft is possible in favourable conditions, the presence of even small shadows and highlights can very easily make the difference between concealed and being sighted. This scheme gives concealment from surface observation on dark nights, in moonlight fully diffused by cloud, and in starlight."
"Scheme F is the basic design for coastal force craft and is for use on all foreign stations. All vertical surfaces and side are painted colour G.45 except those in shadow which are painted White, and horizontal surfaces are painted colour B.15. The remarks on countershading under Scheme E above apply also to Scheme F. This scheme will give concealment at dusk and dawn, in partly diffused moonlight and in starlight in the partly directional light. It will also give fairly good concealment in the conditions for which Scheme E is intended.
Note: Schemes E and F will also give good concealment in overcast weather by day, but in all daylight conditions the bow waves and wakes of boats under way are likely to be more conspicuous than the boats themselves."