Acoustic messaging is possible, but again hard to do. Timed charges are plausible but that's a heck of a commitment (of course 3/4 breaches suggests a possible misfire - I imagine theres a hunt on for the last one).

Even assuming all of these nations record the real-time location of every fishing boat, dinghy, yacht and tug-boat; and can play it back and analyze all of the data; and thereby backtrack to port of entry; and then crew; and then investigate all of the false positives within days. Implausible, but ok, assuming.

But they can find no one, or all the trails run cold. Your next go-to idea for the failure would be Russia or the US?

Come on. Aren't there other plausible reasons?

This is a pretty safe assumption to make. The relevent authorities have this data and are certainly poring through it as we speak.

> Your next go-to idea for the failure would be Russia or the US?

Don't put words in my mouth. I did not allude to anyone in particular, just exclude the possibility of some independent group pulling this off in case the vessels behind sabotage this do not get identified very soon.

I agree that the various coast guards are extremely competent and coordinated, and are poring over the data that they have now. I disagree that capture is inevitable unless submarine.

Someone upstream suggested dragging explosives along behind the boat like an anchor, detonating when detecting the steel and concrete of the pipe. Wouldn't need scuba gear, nor even to stop.