Becoming an Able Seaman
When a sailor starts his career, he begins as an Ordinary Sailor, an OS. And with enough experience and show of skills, he will be promoted to the rank of Able Sailor, AB.
When a sailor is ready for promotion he will be questioned and tested by the Boatswain and the Chief Officer. Asked to name all the parts of the ship and rigging, describe procedures of setting and changing sails. To box the compass, to explain the points of sail, row, sail and scul one of the ship's boats, and to prove his proficiency in marlinespike. Sometimes a sailor will show off his knot tying skills by making a knotboard
Traditionally, a knife is gifted to the sailor on his promotion by the boatswain. This knife will serve like a badge to those who know what to look for. A lot of sailors will get the knife engraved with the ship's name, date and the name of the sea they sailed at that time. To remind them where and when they got it.
There are captains who still wear this knife on their belt, many years after they received it.
A tattoo a sailor might get himself to celebrate this promotion is the letters H O L D F A S T on the upper knuckle of his fingers on both hands. Or a rope around their wrist.
If one receives a sharp object as a gift. Like a knife or a sword. The receiver will pay the gift giver a coin. This can be just a cent. This is to pay off the bad luck, for a gifted knife can sever the bond (of friendship) between the two persons. Or it can be seen as a (murder) threat. To ward off this evil, the receiver will pay for the gift. The total value does not matter, nor does the currency, but it has to be a coin.
If a sailor loses his knife overboard, it is seen as a sign that the sea is calling for him. That he soon will follow his knife and drown. There is no known remedy for this, other than to stop sailing and go life ashore, if you even make it to the next port. To prevent this from happening, a lot of sailors will have a lanyard connecting their knife to their belt. Especially when they work over the side, aloft or up in the rigging.