colregs question

[RichardS]

No it could be where two boats start off roughly abeam of each other and just move together because they steer down the waves differently or something.

Running by the lee in waves, boats can move across the pitch quite a bit. And as they take turns to surge forwards, they can go from showing you a green light to a white, and back. And that's without them altering heading at all, which they may well do.

So two boats, running alongside each other on parallel courses with neither boat overtaking the other, but gradually being drawn closer and closer by different action of the waves on each boat .... and, as they get closer, neither boat can see which tack the other is on so do not know whether to use the starboard rule or the upwind rule?

It sounds like an extremely unlikely situation but would be resolved, as you say, by the requirement to assume that you are the give way boat which would mean steering away from the other boat a tad.

Anyway, someone else can take over from me now as we seem heading further into "angels dancing" territory.

Richard