I found the still photos and I think your are is right. MF was turning to
port, away from SB, and nearly close hauled at the point of collision.
Since she was turning away at the time of collision and giving SB more room,
she might well be blameless. Imagine facing a rub rail repair that costs
more than your whole boat! OTOH, if the original course would have taken MF
astern of SB and SB had maintained a straight course the bulk of the blame
would be on MF.

My best guess at this point would be misjudgement by SB due to the size of
MR combined with a desire to make a close pass. The degree of stern swing
in a turn of a vessel that large will enormous compared to what the SB
operator might expect thinking of her as a "sailboat". A vessel of that
size is of necessity rather shoal in proportion to length. Turning from a
reach to close hauled, it will take a while to accellerate to a speed where
the underbody is fully effective and there will be a few boat lengths of
greater leeway. This could add up to where MF was quickly half a boat
length, a huge amount at this scale, closer to SB than anticipated. Throw
in a few moments of deer in the headlights indecision about whether to head
up or fall off and CRASH!

--
Roger Long