We've had a chance to compare ships in the same harbor before, and the first thing we figured out is that those were in slightly different places in an urban estuary. The wind bouncing off different buildings can vary wildly in relatively nearby spots. I have no idea how built up the Yukanski harbor is, or how warehouses etc. are situated near the various berths. But this may be a way of evaluating how to read the harbor rather than ship accuracy.
The second thing I noticed is one ship has a mercurial barometer, the other an aneroid barometer. The first is raw data needing calculation to include the temperature of the weather instrument cabinet into the equation, the second does not. They are not supposed to be the same.
The third thing is, our gentlemen seem to disagree about what is rain or a passing shower or misty drizzle, but they both agree it is a cool, damp, humid, cloudy day.
But the point that really interested my is that their thermometers, both dry and wet bulb, are calibrated differently. The difference is temp is consistent and obvious. I wouldn't be the least surprised if the team didn't average the readings and then use this information to slant all other readings off both these ships for all of 1917. And probably thank us for this find.