Here, we're basically driving home the point that, after the Nore mutiny, anxiety is rampant in the British fleet.
Though the mutiny won a few victories for the sailors, like getting the people who sold the crews goods not to provide them with junk, it also left a lot of their demands unfulfilled. To boil it down, things were tense.
One example of just how tense is that Lord Nelson was intentionally shifted from his ship to one of the ships that took place in the mutiny, because it was thought that he might be able to win the men over with his personality.
He did, but there were still many captains who thought of their crews as powder kegs ready to blow.