After reading the log, they were probably trying to get morale back up after chasing the humpback and coming back empty-handed the day before. Also, I can't help but wonder if the crew were maybe making trenchers. It takes an awful lot of calories to keep a crew hardy while at sea, especially on fishing vessels (and whaling vessels even moreso, obviously), where the work is incredibly physical by nature. A trencher of an average size, with beef and pork, assuming the meat had been cured prior to cooking (in this case, salted, possibly smoked or pickled, but just going with salted for the purpose of counting) runs a bit short, but in the neighborhood of 1,000 calories (between 850 & 1100 depending on the curing method for the meats).
Modern commercial fishermen (at least on the boats I've worked on) can burn upwards of 3,000 calories a day, and this is on vessels that are powered by engines, rather than wind. I'm not a nutrition expert, or a fitness expert, but I'd wager that our whalers would be burning a bit more than that. Exhaustion, hunger, and bad fishing can turn crews into raging, murderous, mutinous beasts in relatively short order. After missing out on a haul, and having (from what I can see) less than stellar opportunities prior to that, a belly full of meat and bread would go a long way toward keeping the crew from taking their aggression out on each other (or worse, on the captain).