My Speculation on USS Fitzgerald – ACX Crystal Collision

USS Fitzgerald



ACX Crystal



Crystal Vessel Track

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



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.



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:

T-1   17:45 UTC ?


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.

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.


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;

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