Substitute to Morse Code Flag Correspondence

If you look at your average International Maritime Code Flag chart they will often have substitute/repeater flags listed.  Since it would be cumbersome to have multiple flags, substitute flags were created that repeat certain positions.

Morse Code is often put next to the flags, but there is little relationship between Maritime Signal flags and Morse Code.  Nor is Morse Code listed for any of the signal to the substitute flags.  Likewise many websites often forget to list the 4th position substitute.


But finally today, we have Morse Code Substiute Flags and Morse Code prosigns to go along.  These flags are based upon three letters, always starting with S for Substitute which has three stars.  Consequently the Morse Code flag for 1st Substitute is SST; the first S comes from Substitute and the ST comes from st in 1st.

Unlike the other Morse Code flags that have their colour code based upon the order of the spectrum, the colours of Morse Code Substitute flags follow the colour pattern already established by International Maritime Flags.