First, I'm very dissatisfied with this. It was probably a mistake to post it in its current form, and if the competition had attracted more entries I would not have done.
It tries, without much success, to draw together several strands. I wrote most of the section starting "unearthly" first. Its final form contains references of varying obscurity to Socrates, Shakespeare, Coleridge, Wordsworth, Wagner, Gilbert and Joyce; but they seem arbitrary - I cannot honestly say they form anything.
The last section, on Royal Company Island is factual (the reference is "Islands of Adventure" by K. Baarslag). I also have a book at home, a compendium of accounts of the voyages of Drake, Anson, Dampier and Cook, that shows the Royal Company Island(s) on its illustrative maps (not that any of the voyages passed anywhere near the supposed position of the island or mentioned it in their logs).
I would like to have written a genuine story based on this oddity, and the section starting "There is a persistent legend" was as near as I came. I suppose there is a hint of a variation on the Flying Dutchman legend using the well worn "place that only appears from time to time" theme.
Finally I tried to pull these bits and pieces together with a framing story of the legacy of an elderly man. The links, such as they are, turn on 1904 - specifically Bloomsday, June 16th 1904, which is by implication the day "my father's friend" was born (and is the supposed reason for the mangled form of the first sentence of Ulysses - "unearthly" for "stately"). Oh yes, "the flowers that bloom in the spring".
Now it's fairly obvious that the "unearthly" section will not do as any sort of translation of the "note in Friesian". It's manifestly twentieth century. Looking at a detail here, "Nick Alligin" for "Buck Mulligan" is not ideal. "Nick" suggests a diabolic adversary; but why "Alligin"?. I had considered "Flanagan", but settled on the name of a mountain which suggested something reptilian. And this, in turn, may suggest what was actually going on.
So, although the whole thing could be dismissed as self-parody, I could claim that the bits and pieces represent the confused ramblings of an aging man reflecting on anecdotes and conversations of half a century earlier. And this may be taken as an explanation of the piece, either as a fictional construction, or in fact.