Friday the 13th and Other Unlucky Days in Maritime History

For centuries, sailors have been known for their superstitions. From avoiding certain words onboard to believing particular animals brought bad luck, maritime history is full of unusual traditions.

But did you know that some sailors were also extremely particular about the day they set sail?

In fact, choosing the wrong day to begin a voyage was once believed to invite everything from terrible weather to shipwrecks and other disasters.

And when it came to supposedly unlucky days, Friday had a particularly bad reputation.

So why did sailors fear Friday departures? What made Friday the 13th even worse? And were there other dates that seafarers preferred to avoid?

With Friday the 13th just around the corner, we thought we’d take a look at the calendar-based beliefs that influenced maritime traditions, and how they developed over the centuries.

Why Was Friday Considered an Unlucky Day to Set Sail?

Long before Friday the 13th became associated with horror movies, Friday itself was regarded with suspicion by many European sailors.

The belief was particularly strong in Christian maritime communities, where Friday was associated with the crucifixion of Jesus Christ.

Because Good Friday commemorates the crucifixion, some people believed that beginning an important undertaking on any Friday could bring misfortune.

For sailors preparing to embark on a potentially dangerous voyage, this was not a risk they wanted to take.

The superstition became so established that it appeared in maritime reference works. Admiral W. H. Smyth’s The Sailor’s Word-Book, published in 1867, described Friday as a day on which older seamen were reluctant to get underway because they considered it unlucky.

Of course, not every sailor believed this, and commercial or operational demands did not always allow captains to choose their departure days.

Nevertheless, the idea that Friday was a poor choice for setting sail became one of the best-known calendar superstitions in maritime folklore.

Why Was Friday the 13th Even More Unlucky?

Friday already had a questionable reputation, but combining it with the number 13 created what many people came to regard as an especially unfortunate date.

The number 13 has long been associated with bad luck in parts of Western culture.

One frequently suggested explanation comes from the Last Supper, which involved Jesus and his twelve apostles, making thirteen people at the table before his arrest and crucifixion.

However, the history of Friday the 13th is not quite as straightforward as many people assume.

According to research published by the Library of Congress, clear written references to Friday the 13th being unlucky appear in French sources during the 1830s.

This suggests that the combined superstition became established considerably later than some of the older beliefs about Fridays and the number 13 individually.

For superstitious sailors, however, the combination was hardly reassuring.

If Friday was already a bad day to leave port, Friday the 13th could seem like an even worse choice.

The Curious Legend of HMS Friday

One of the most entertaining stories connected with unlucky sailing dates concerns a supposedly ill-fated British Royal Navy vessel called HMS Friday.

According to the legend, the Royal Navy became frustrated with sailors refusing to begin voyages on Fridays so to prove that the superstition was nonsense, they supposedly commissioned a ship called HMS Friday.

The story claims that:

• The ship’s keel was laid on a Friday.
• The vessel was launched on a Friday.
• Its captain was named James Friday.
• The ship departed on its maiden voyage on Friday the 13th.

Neither the vessel nor its crew was ever seen again.

It sounds like a perfect maritime horror story.

There’s just one problem.

HMS Friday never existed.

The story is a maritime urban legend, not a documented Royal Navy disaster. Earlier versions of the tale circulated with different details, including accounts involving privately owned merchant vessels rather than the Navy.

Its popularity demonstrates how firmly the belief in unlucky Fridays had become embedded in maritime storytelling.

It also provides a useful reminder that not every supposedly historical maritime disaster actually happened!

Were Thursdays Considered Unlucky Too?

Friday wasn’t the only day to attract suspicion.

Some collections of maritime folklore also identify Thursday as an unfavorable day for beginning a voyage.

The explanations vary, but one traditional belief connected Thursday with the biblical story of Cain and Abel.

According to certain interpretations passed down through folklore, Thursday was the day Cain killed his brother Abel.

There is no biblical evidence establishing Thursday as the day of the murder, but the association became part of some collections of unlucky-day traditions.

It’s important to remember that these beliefs were not universal.

Different maritime communities developed their own traditions, and a day considered unlucky in one culture might have had no particular significance in another.

What About Other Unlucky Dates?

Historical calendars and collections of folklore sometimes identified specific dates as unfortunate for travel or major undertakings. There are also maritime superstitions and folklore centered around Christmastime.

One particularly interesting tradition involved so-called Egyptian days, also known as dies aegyptiaci.

These were days considered unlucky in certain medieval European calendars, and people were sometimes advised to avoid activities such as traveling, beginning important work, or undergoing medical treatment.

The precise dates could vary between traditions and manuscripts.

Although these beliefs were not exclusively maritime, they illustrate the wider culture in which sailors’ superstitions developed.

In an era when voyages could take months and ships faced considerable dangers, it is understandable that some mariners might have paid attention to warnings about particular days.

The idea of an unlucky departure date was therefore part of a much broader historical fascination with fortunate and unfortunate times.

Did Different Cultures Have Different Unlucky Days?

Absolutely. The reputation of Friday the 13th is especially familiar in Britain, the United States, and several other Western countries, but it is far from universal.

For example:

• Great Britain and the United States – Friday the 13th
• Spain and some Spanish-speaking communities – Tuesday the 13th
• Greece – Tuesday the 13th
• Italy – Friday the 17th

Obviously, these are general cultural beliefs rather than rules followed by all sailors in those countries.

Tuesday’s reputation in some Mediterranean traditions has been linked to associations with Mars, the Roman god of war, and historical events such as the fall of Constantinople, although explanations vary.

Italy’s association with Friday the 17th is often connected to interpretations of the Roman numeral XVII, whose letters can be rearranged to spell VIXI, a Latin expression meaning “I have lived,” sometimes interpreted as implying death.

These differences show how ideas about unlucky dates developed through religion, language, history, and local customs.

Therefore, a date that worried one group of sailors might have seemed perfectly ordinary to another.

How Did These Maritime Traditions Develop?

It’s easy to dismiss unlucky sailing dates as old-fashioned nonsense, but they developed during a period when going to sea was considerably more dangerous than it is today.

Before modern weather forecasting, satellite navigation, and reliable communications, sailors faced enormous uncertainty.

A vessel might disappear during a storm without anyone knowing exactly what had happened.

When disaster struck, people naturally searched for explanations.

If a ship happened to depart on a Friday and subsequently sank, the coincidence could reinforce an existing belief that Friday was unlucky.

Meanwhile, countless vessels that sailed on Fridays and arrived safely attracted much less attention.

Over generations, stories were repeated, exaggerated, and passed between sailors, families, and maritime communities.

Religion, local folklore, and traditional calendars all helped shape these beliefs.

What began as a general cultural superstition could eventually become an established maritime custom.

Do Modern Seafarers Still Avoid Unlucky Dates?

Today, commercial shipping operates according to schedules, port availability, cargo requirements, weather conditions, and operational considerations.

A container ship is not generally going to delay its departure simply because the calendar says Friday the 13th.

Modern maritime safety depends on professional seafarer training, risk assessments, vessel maintenance, weather information, and established procedures rather than lucky or unlucky dates.

Nevertheless, traditional beliefs remain an interesting part of maritime culture.

Some seafarers may still observe particular customs for personal or cultural reasons, while others regard them as amusing reminders of shipping’s colorful history.

And even the least superstitious sailor might occasionally joke about setting sail on Friday the 13th.

After all, why tempt fate?

Frequently Asked Questions

Why did sailors believe Friday was unlucky?

The belief is commonly associated with Christian traditions surrounding the crucifixion of Jesus on Good Friday. Over time, Friday acquired a reputation as an unfavorable day to begin a voyage in some maritime communities.

Was Friday the 13th always considered unlucky?

No. Although Friday and the number 13 had separate negative associations, clear written references to the combined Friday the 13th superstition date from the 19th century.

Did HMS Friday really disappear at sea?

No. HMS Friday is a maritime legend and urban myth, and there is no historical evidence that a British Royal Navy vessel with that name ever existed.

What were Egyptian days?

Egyptian days were dates identified in some ancient and medieval calendars as unlucky for important activities, including beginning journeys. Different versions of these calendars existed, and the dates were not universally observed.

Do shipping companies avoid departures on Friday the 13th?

Modern commercial shipping schedules are determined by operational, commercial, and safety requirements rather than traditional superstitions. There is no general maritime regulation prohibiting departures on Friday the 13th.

A Final Thought: Would You Sail on Friday the 13th?

For centuries, the calendar could be almost as important to a superstitious sailor as the weather.

Fridays were approached with caution, certain dates were considered dangerous, and tales of unfortunate voyages helped keep these traditions alive.

Today, we know that the day of the week has no bearing on whether a ship will complete its voyage safely.

But the history of unlucky sailing dates provides a fascinating insight into the lives and beliefs of earlier generations of seafarers.

And if you’ve found a job through ProSeafarers’ maritime jobs site and happen to be joining a vessel on Friday the 13th, there’s no need to worry.

Just make sure your documents are in order, your travel arrangements are confirmed, and you’ve packed everything you need. Those are much more useful precautions than checking the calendar!