



Brown 1943 and 1951 show a blue flag with two widely spaced narrow white horizontal bands and a white S between them. Rosanoski doubts the attribution because the letter seems inappropriate. Stewart 1953 shows the yellow-and-black flag, but whether this was an actual change remains uncertain.
Rosanoski assumes the funnel yellow matches the flag. Phil Nelson’s FOTW illustration follows Stewart 1963.
This version comes from the undated Amsterdam harbour flagchart.