Real-life sailors tend to be very superstitious; given that the 40Kverse is already pretty superstitious, it seems to me that their equivellant of 'sailors' would be extra superstitious. What counterparts to "Never start a voyage on a Thursday" and "It's bad luck to kill an albatross" do you think there would be in the 41st century?
Voidfarer superstitions?
If you are born during an encounter with a void-whale, your fate is blessed by the Emperor.
If you are born during a warp transition, you are cursed by the warp and a pox upon the crew - treated with animosity.
A Gargoyle or Devotional Statue that falls as you're walking by is a bad omen for your shift.
The Litany of the Emperor must be spoken by at least one voice at all times during a Warp transition. This will require more than one person, as pausing for breath or between words counts as the prayer no longer being spoken.
If a Servo Skull is the first thing you see when you wake up, then the machine spirits will smile on you this day.
The longer your ship goes without a death, the more catastrophic the next one will be.
Withdrawing from port while facing the Eye of Terror curses a voyage.
Eggs must not be eaten before your shift, only after.
(one thing to remember, many superstitions come from misunderstood correlations; they may be actually (slightly) correlated, or appeared correlated once or twice by chance, before becoming a superstition. Hense why morest superstitions are to avoid bad things.)
Before firing a cold drive the chief enginseer and drivemaster must stand near a canister of pure water and discuss the previous day's events for at least 15 minutes. Upon depressing the ignition rune the drive master must also kick an available section of the engine casing to help wake the machine spirit.
All hammocks should be woven with at least a few strands of hair from a priest of the Ecclesiarchy to ensure good restful sleep and protect against the evils of the warp.
The longer a voidsman goes without grog or rum the more likely he will be to be infected by an evil spirit.
If a hullgast (mutant) ever becomes an officer the ship will be cursed with bad luck.
At least one rating must urinate on a torpedo as it is being loaded otherwise it will missfire.
Never say: "it's a good thing the geller field is holding out." as this will cause it to collapse.
It is bad luck to whistle in the enginarium.
Inquisitors on board are bad luck.
When translating into the warp count backwards from 64 to placate that wich dwells in the warp.
Kissing a servitor will bring good luck: the uglier the servitor, the better.
Inquisitors on board are bad luck.
Well, that's not superstition, that's just a statement of fact...
Blood makes the holy unguents spread evenly.
Incense purifies the air. Rendered down witch fat will do in a pinch. :::everyone glances at the astropath:::
Ships that aren't named in the Emperor's glory disappear more often.
Never speak of another's misfortune, lest their misfortune spread to you.
Children born during a gunnery duel with another ship is blessed to be a skilled duelist themselves.
Throwing cursed people out of the airlock helps with warp transit.
Throwing snotlings into the plasma drive eases the activation of the cold drive, as the ship despises orkoid kind (and helps with that whole infestation thing XD, no need to mention how often the generators need cleaned because of this)
Playing any game of chance during warp transit is also tempting your own fate, and others may consider you cursed (see above)
When in warp transit, never knock on the outer hull. It brings bad luck.
Do not light candles directly from other candles. It is said that this kills a voidsman, somewhere.
Two servitors crashing into each other is nothing to bother about. Two servo skulls crashing into each other is a bad omen for the next warp journey.
Voidsmen who die in the warp are to be stored as close to a shrine as possible until they can be properly buried at void.
Tools dropped out in the void while doing repairs are considered cursed.
Make sure dirtside debts are paid before leaving port. Voidsmen in debt are not in themselves unlucky, but they make every other omen worse. The bigger the debt, the greater the distance, the greater the curse.
It's bad luck to have psykers on the bridge.
The last shell from a case of munitions must never be fired in anger, or dire things will happen.
Only small ships may approach docking stations from any direction; capital ships must "catch up" to dock along its orbit.
Pray to the Emperor for a safe landfall before leaving port. Once the ship is underway praying for a safe landfall will curse the voyage.
The 13th deck is cursed. A tech-priest must visit the deck every day to commune with the machine spirits of the equipment that lives there lest they rebel.
all crew: Never step directly on the seal, gasket, or join when passing through an airlock.
I win. No-one can top those superstitions.