Ship knocking
The history of ship knocking as its referred to among the crews in the navy is a tradition carried on in the navy for many years.
As with so many traditions in the military, no one is quite sure when this one appeared but it's common knowledge that sailors, it being sailors of old wooded ships or great battleships sailing between the stars, are a superstitious bunch. The sailors who do it will swear that the knocking working and that they have heard stories about crews who didn't do it and never returned from a hyperspace jump.
It said that knocking on the top of the airlock before entering is said to keep bad luck away and bring luck to the ship in return. Civilians and scientists will insist on it being just pure superstition, the crews like to point out that ships, where this tradition is observed and carried out, will have a higher chance of returning from dangerous missions or just, in general, do better in exercises.
One of the guys in the messhall told me that his brother had served on the ESS Jupitor and that they only returned thanks to ship knocking being a thing abord
- Crewman talking to a journalist about the recent return of the Jupitor.
Execution
The knocking can be different depending on the ship in question, but it is typically three knocks with a closed fist and where the difference lies in the way the hand hits the top frame of the airlock, it can be with the knuckles or it can be with the side of the hand or top or bottom part. It differs from ship to ship and new ones are quick to learn the right way of knocking when boarding a navy ship.
Participants
Civilians are not expected to participate in the tradition but its common that once they have been explained the reason behind it, that they will participate as well in the future when entering a navy ship.
Observance
An outsider might observe the tradition if they were to board a navy ship, were they would experience that every crewmember that were to board the ship would knock on the top of the airlock door before entering the ship.
Related Organizations
What happens if it knocks back?
You have a ships AI taking the piss on you.
Or the gremlins