Earlier today, I put ARCTUROS into marinetraffic.com and looked at the her past track and speed. I plotted the location of a speed reduction to Navionics and the position is marked by the “crosshairs” on the attached screen shot.
Not any conclusion, but the information indicates to me that the incident did not occur in the entrance channel. Indeed the entrance-proper has soured many weekends…we have seen it ourselves.
To be clear, I am NOT slinging mud here…only pointing out the probable location for safety and awareness of ourselves and others.
Agreed, the track recorded by Marinetraffic does look fairly supportive of hitting a charted rock. I uploaded a recording of the playback:
https://adobe.ly/3w0n7As Attached is a screenshot of the NOAA Raster chart of the location.
If my calculations are correct this would have been just after 8pm on Friday Aug 5th, which was just above a 6' tide and within half an hour of sunset. The symbol for the rock I drew the arrow to (just a guess, obviously) means "Rock awash at the level of chart datum" so that could definitely be an unseen but dangerous rock at that tide level.
Please note that this track is not a full depiction of reality. It is only as good as the data the vessel was sending, and the track between data points (which, sometimes confusingly, are not just the places with the arrows marked) is interpolated. It doesn't consider other traffic, etc. The speeds and positions at the arrows should be accurate based on what the vessel reported, however everything between is subject to interpolation (ie. made up).
This is pure speculation, however if I were in that situation I could easily imagine it being late, trying to get in before sunset, and being focused on reviewing the "known dangerous" tricky entrance and thus missing this danger. Again, pure speculation based on me thinking how I could end up in this situation: this is especially true if you are trying to use your primary chart plotter to review the entrance while still underway at 8 knots.