The old canard (which by the way means "duck" in French, so I'm always particularly tickled by its usage in English - as always, words don't have to make sense to be fun!) is that sailors despise a woman aboard ship. We've certainly seen that women went to sea long before modern navies got over their squeamishness and put women solidly among many a crew, but how each individual mate on each individual ship felt (or feels) about it is open to speculation. The story is women brought trouble, caused jealousies and infighting and could lead to the very worst possible outcomes. Patrick O'Brian uses this premise in more than one of his Aubrey/Maturin novels to great success. "The Far Side of the World" in particular features a love triangle between the gunner, his nubile wife and an older midshipman that has the most tragic of consequences.
Interestingly, the superstition included a clause that stated a naked woman aboard ship brought good luck and protection to the barky. Hmm. Sounds like sailors thinking wishfully, doesn't it? Well, maybe, but...
In 77 AD Pliny the Elder wrote in his voluminous "Natural History" that "...out at sea, a storm may be lulled by a woman uncovering her body..." How handy is that? One has to wonder if Roman ships kept a woman below to climb up on deck and reveal her charms when the weather turned awkward. I know more than one of you is liking that idea. But no, they didn't do it that way as a rule. Instead they invoked the female force of protection at sea less literally, and many still do today.
The Goddess of the Double Axe worshipped at Knossos in ancient Crete with her breasts bare was not only the Great Mother in that culture but the protector of ships at sea. The Egyptian Isis (Au Set in the ancient language) was considered a universal protector of ships and shipping. When her worship spread across the Mediterranean, Roman, Greek and Carthaginian ships were routinely named for her and small amulets with her name were worn by seamen. The Norse goddess Frigg, wife of Odin, was called upon by all who went to sea for safety and good hunting.
To this day, Catholic sailors have a special affinity for the Virgin Mary. Fishing villages in southern Europe and South and Central America almost uniformly feature a church dedicated to Mary, many of which have small chapels or altars set aside for sea goers and their families. Stella Maris - The Star of the Sea - is Mary's incarnation as the queen of the oceans and in Haitian Voudon her counterpart is La Siren, the mermaid who will grant safety on the water or entice people to a watery grave.
Ships were routinely named Mary, Maria, Marie or any combination that included the Virgin's name. Columbus famously had his Santa Maria and the Spanish Armada that had such bad luck against Elizabeth of England's sea dogs contained at least ten ships with Maria in their name. Pirates and privateers were no exception, and in the early 1800s the Gulf of Mexico was jam packed with ships named Santa Maria, Maria Corazone and Estrella de Mar. In fact, Mary's name even includes the Latin word for sea.
Finally, the rage for female figureheads with one or both breasts bared may stem from the idea of the female body calming the waves. Before the 17th century, figureheads tended to be mythical or known animals. Lions and rams were popular, but so were dragons and griffins. As the Reformation marched across Europe, though, the attachment to the Virgin for protection at sea waned, particularly in northern Europe and North America. It doesn't seem like much of a coincidence that by the 18th century ships - even those with names that weren't feminine - had female figureheads. Though the form of invocation had changed, our superstitious mates were loath to give up their goddess.
Aside from all that, figureheads were and still are beautiful pieces of the woodworker's art. Many port cities have mariners' museums and a trip to one of the larger ones will probably bring you face to face with some of these delightfully fanciful figures. Check them out if you have a chance, Brethren. What is more inspiring than standing next to history?