The first act of the watch is to update the log,
The last act of the watch is to update the log.
Ok, I don't want to start being picky because its not the intent of anything here... But just 'saying' things that don't conform to reality just makes the poor crews job confusing and irrelevant.
The first thing one does on watch is to take the hand over from the previous watch keeper. Then go out on deck and sail the boat.
It can't be to update the log because that has just been done by the retiring watch keeper. Not only that but the new watch keeper will be wrong in what he puts in the log because he hasn't been sailing the boat since hi sprevious watch. So if he looks, for example at the wind meter and writes that in the log he doesn't know if its a gust, average, high or low. Same with direction, heading, current etc etc. he needs to go straight on deck and sail the boat and then update the log at a suitable time lapse. (Which I recommend every 4 hours, but every skipper is different).
Disagree with the shipping lane stuff too. If you bore the crew senseless they will be senseless and fall asleep at night, shipping lane or not.
What I feel important is the watch keeper to have a watch that interests him enough to keep him excited and awake. Better to have a speed competition with the other watches than bore him by reefing because its night. Or having too short a watch - if its only a 2 or 3 hour watch its not long enough on a sail boat to get anywhere... You can see two hours forward... But four hours coastal you have seen a lighthouse from nothing, thru loom, to light and then back to darkness... Weather is the same: four hours has given a cycle of weather even in the tropics it's never the same over the watch.
By giving excitement and not being pedantic you give the crew the things they want. And if they are not then repos able enough to be left of deck unsupervised then you need to retrain them or replace them.
There is theoretical safety and practical safety and in cruising I feel it should err on the side of practical or you will be without crew! Or wife! If one is in the Navy it's different. There you can spend three hours writing the log because there's others looking out the window... And there's other to keep you awake during the graveyard shift. But that theoretical safety isn't going to be safe when there's only one on watch on a cruising boat.