For those who don't know, "Spanish Ladies" is an 18th century sea shanty whose chorus goes,
We'll rant and we'll roar, like true British sailors,
We'll rant and we'll roar, all on the salt sea,
Until we strike soundings in the Channel of Old England;
From Ushant to Scilly is thirty-five leagues.
The Oxford English Dictionary lists one of the meanings for rant as a riotous, boisterous merry-making, in the Northern dialect by 1675. A related possibility for rant would be the rant step, a very common Northern step dance.
Its not for nothing that Churchill listed The Lash as one of the three traditions of the Royal Navy. Much of the force was conscripted, or as they called it at the time, impressed, into the service. In many cases this was done by physically grabbing random men off the streets of port and coastal towns. These men were usually very unhappy about this, and kept in line with rigid, harsh punishment. These men were almost universally illiterate or uneducated for very good reason. Though they were familiar and skilled at the menial labor a sailing ship required, none of them new how to navigate. Mutinies were kept in check not only by the threat of punishment, but by the knowledge that only the officers knew where the nearest source of fresh water was. So muttering, complaining, griping, and all manner of divisive talk was relatively common, actual mutiny was rare, even from men who had been basically kidnapped.