First, here is a pretty good summary of what has taken place (including videos) posted by RT:

I will just add that at the time of writing (07:38 UTC) the cargo ship blocking the passage under the bridge has been removed, traffic has resumed and the situation has returned to normal.

Second, let me give you the single most important element to understand what is (and what is not) taking place: the Sea of Azov and the Black Sea are, in military terms, “Russian lakes”.  That means that Russia has the means to destroy any and all ships (or aircraft) over these two seas: on the Black Sea the life expectancy of any intruder would be measured in minutes, on the Sea of Azov in seconds.  Let me repeat here that any and all ships deployed in the Black Sea and the Sea of Azov are detected and tracked by Russia and they can all easily be destroyed.  The Russians know that, the Ukrainians know that and, of course, the Empire knows that.  Again, keep that in mind when trying to make sense of what happened.

Third, whether the waters in which the incident happened belong to Russia or not is entirely irrelevant.  Everybody knows that Russia considers these waters are belonging to her and those disagreeing with this have plenty of options to express their disagreement and challenge the legality of the Russian position.  Trying to break through waters Russia considers her own with several armed military vessels is simply irresponsible and, frankly, plain stupid (especially considering point #2 above).  That is simply not how civilized nations behave (and there are plenty of contested waters on our planet).

…click on the above link to read the rest of the article…