Extract from a mail from James Duff concerning revisions to RN colours in the Colour Coats range. (Sovereign Hobbies).
"Deck coatings, and particularly Semtex is more complicated than is shown here - there were at least 3 brands of latex based trowel-on deck coatings of which Semtex was one brand, and each brand was a different colour."
The make it go bang stuff was developed late 50s in Czechoslovakia I believe.
Named after the place it was made from 1964. Colour is usually red/brown or orange/red.
More info on the Semtex green paint for modellers (unless you like trowelling on your deck paint😁) is here
Much too dark for the Pilot Boats.