There are no records of any major hole digging until about 1850, when machines were available to do the work, and a 200 foot hole was child's play for them, and the legend of the treasure was already firmly in place.
There's a huge problem with the idea of a 200 foot hole having been dug on the island in the early days. There's no record of any of the excavated dirt. There's no record of the lumber yard and tools that would have been needed. You should have had an enormous dirt pile, lots of lumber, lots of tools and rigging, etc. It would have involved a large crew, a large workyard, buildings, lots of tools, etc.
Think about it yourself. You are going to dig a large 200 foot deep hole on a forested island with just men and hand tools. It's an enormous project that requires enormous resources. It would leave an enormous footprint on the island, visible long after the hole was abandoned.
There's never been a sign of any such project on oak Island prior to the arrival of machinery to dig for treasure around 1850.
The five fingers drain system was probably for making salt to preserve fish, without having to pay taxes on the salt production.
Claiming to know where treasure is buried was, and still is, a common way to get people to give you money.
Also, selling treasure hunting licenses was a common way to get money.
That is at the root of the Oak Island treasure myth, imo.
There's no evidence at all for most of the base claims about the island and the pit.
Anything at the bottom of the pit or pits, most likely fell in there during one of the multitudes of tunneling and collapse cycles over the decades.
If there was a enormous project to make a 200 foot hole early on, there should be lots of dropped tools, broken tools, discarded lumber, abandoned buildings, and other leftovers from that project.
The island has literally been "swiss cheesed" with all sorts of holes at all sorts of depths and angles. Holes were dug, collapsed, and dug again decades later. This cycle repeated over and over again.
There is no longer any "original hole", if there ever was one. There are dozens and dozens of dig sites on the island. Many overlapping and criss-crossing sites and tunnels all over the place.