Both you and @radix@lemmy.world came to the same conclusion I did that “operating astern” might mean “we are slowing down” but the impression I got from Wikipedia was that flag was for literally travelling backwards, and the ship is clearly not doing that.

Interpretation 2 is that the first flag is the blue Peter referring to obstruction (usually fishing nets) and it is instead a reference to Jucika herself, kind of a “hey, you, the thing in our way”.

Interpretation 3 is the in-port meaning of the same flag, which is “come aboard”

The third flag about having a pilot aboard is also a little weird and I can’t be sure whether he’s saying the ship has crew or whether they’re asking if she needs guidance back to shore.

Still fairly mystified by Jucika, especially the spotted neckerchief. Spots don’t seem to be a good match to anything.

… though I do like the idea that the shorts mean she might be calling herself a firecracker.

The top flag may be a blue Peter, but I think the slowing to a stop interpretation makes more sense. I’ll bet you a nickel this strip is printed on newsprint using a limited color process that can’t reproduce blue, so we may never know. (I imagine if they could it would have been used in the water at least a little bit.) That was extremely popular in the '60s and '70s to keep costs down, and there are tons of ads out there from those eras designed around one or two color printing. I also had a pile of children’s books from back when which did the same and forced the authors/artists to make some… strange… color choices and omissions.

The registration is also exceptionally awful here and reveals that they’re apparently only using black, magenta, and yellow. I imagine Jucika’s kayak is actually meant to be red, and it would be except for the registration miss:

That’s also why the polka dots are falling off of the fabric…