Tradition - Silver Coin Under Mast

An important part of sailing is tradition.
I have embraced learning and taking part in the traditions and lore of sailing.
This week I have been enjoying the search for the proper coin(s) to put beneath the mast before the mast is restepped.
There appear to be different versions of this tradition.
In some instances a gold coin was to be placed beneath the mast when a ship was built to pay the toll to the ferryman (the reaper) to cross the river Styx if the ship was sunk.
Some say to place a silver coin beneath a mast prior to restepping the mast for good luck.
The coin may have the date of the building of the boat, the birthyear of the namesake, or some other significance. And, if the mast comes out, those coins are to go back in !
There was no coin found upon removal of Athena's mast. Thus the search for a proper coin began.
And, one was found.

A 2100+ year old Greek silver Tetradrachm, minted in Athens between 146-145 BC.
Obverse: Head of Athena facing right, wearing a crested Athenian helmet.
Reverse: Owl standing right on prostrate amphora, head facing, cock with palm and magistrates names in field.
Size: 33 mm 1 1/4"
Weight: 16.6 grams of silver
The coin bears ancient test cut on the cheek of Athena. Cuts such as this were often used to verify the precious metal of coins when presented to ancient money changers for conversion to another currency.

To go along with this precious coin, my mom is giving me one of her silver dollars dated 1972 (my birth year). I'm hoping she has one from 1978 too, the sailboat's birth year.

The pieces are slowly falling together.