ΔE 31.4, loose: different enough that you should pick on purpose. Grey Spell is a little darker, much more muted, warmer than Raging Sea.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 31). Grey Spell is a little darker, much more muted, warmer than Raging Sea.
The same difference applies the other way round: Raging Sea is a little lighter, much more saturated, 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 Raging Sea on the colour wheel See Grey Spell on the colour wheel
All matches: Raging Sea equivalents · Grey Spell equivalents