ΔE 15.1, loose: different enough that you should pick on purpose. Phthalo Blue RS is much more saturated, warmer than Triumphant Navy.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 15). Phthalo Blue RS is much more saturated, warmer than Triumphant Navy.
The same difference applies the other way round: Triumphant Navy is much more muted, cooler.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Triumphant Navy on the colour wheel See Phthalo Blue RS on the colour wheel
All matches: Triumphant Navy equivalents · Phthalo Blue RS equivalents