My Speculation on USS Fitzgerald – ACX Crystal Collision

USS Fitzgerald

Fitzdwg

FitzphotoFitzchar

ACX Crystal

Crystalph

Crystalchar

Crystal Vessel Track

The Crystal’s track from an Automatic Identification System (AIS).

CrystalTrack
Credit Freerepublic.com

 

This plot appears to show the Crystal making a 90° port turn into the collision at 17:29 UTC (02:29 LT)

A finer scale time lapse animation of the ACX Crystal’s track is available on YouTube.   From this we get this tract, I have added approximate course of Fitzgerald and event times from the AIS time tags.  There is a discrepancy in the times, if I read the Marine Traffic time stamps correctly, and it is UTC, there is a one hour difference, that need to be resolved.  The T-4 time tag is approximate position of Crystal at 17:30 according to Marine traffic’s time stamp.

MarineTraf

 

If the AIS data is correct, and the collision occurred at T-3,  the ACX Crystal was on a parallel reciprocal course from the Fitzgerald when it did a 180° turn to port at T-1 (17:45 ?),  Then at T-2 (18:28 ? ) it did a 90° turn to port before colliding with the Fitzgerald at T-3 (18:35 ?).  The reported time were:

Time1
T-1   17:45 UTC ?

 

Time2
T-2   18:28 UTC ?

My T-3 is about the time of the collision, based on the vessel track, not the reported time of the collision.

Note: I find it strange that the mainstream news media hasn’t purchased a copy of the Marine Traffic data and presented an analysis similar to this.

Time3
T-3   18:35 UTC ?

From AIS reporting it appears the normal cruise speed of the ACX Crystal is 20 kts.  I will assume, based on the “30 knot Navy” that the Fitzgerald was like doing 30 knots or more, overtaking the Crystal.

Alternate Scenario

If the collision occurred at T-4 then the Fitzgerald track would have had to been 90° to the Crystal track, heading northerly.  The Crystal’s post collision track would have been loitering in the area.

Questions

The erratic track of the ACX Crystal prior to the collision (T-3 or T-4)  certainly raise the possibility of some form of mechanical failure.

Likewise the 90° turn to port just prior to the collision (T-3)  raises the possibility of an intentional ramming.

I will leave it to those more knowledgeable to comment on the lane separation distance, T-3 scenario.

June 20 Update

Another AIS video, annotated with vessel speed; https://youtu.be/m1b58yelh_c

Just to add a little more fog to the narrative, the time of the collision is now in question, according to Daily Mail article.