I feel sure the military would use Stockholm Tar, for that authentic scent that really
sticks to your hands.
(I have (UK) mast stays that were treated with the stuff (for the 34-ft and 36-ft masts. The post-WW2 versions used synthetic rope (Terylene or polyester), so are a bit nicer to handle. The WW2 Canadian 20-ft and 34-ft telescopic mast kits seem to use untreated white cotton (Or possibly linen?) sash cord for the stays.)
Chris.