Thanks, Tor, I had overlooked that one is in decimal and the other in minutes.
I now think that the camera timestamp is automatic and therefore the more reliable (also more recent)
looking at the data on the ship track site, there is what looks like a decimal point slip in temperatures (44 deg water temp at 00:00 on the 11th ?) so these are probably entered by someone by hand and therefore more likely out of date.
but:
pos given at 13:00 on 2015/07/11: 71.40 / 160.60 on sailwx
is a close if not exact match to photo 20150711-1301 71.463 / 160.586
what made me question the times was originally the observation that water temperatures were lower with little ice at 13:00 than at 18:00 with more ice seen. With your help I now am convinced that this is genuine, The large floes seen at 18:00 can probably last for a while in water of 4.5deg.