It sounds like you didn't read it, because he tells you where the effect occurs and where it is less likely to occur.
Odd that you won't simply answer the question in support of your model.
A or B?
You can read about the sinking effect in the Wiki and Earth Not a Globe and other FE literature. It's part of FET. It would be better if you read more and post less.
Definitely odd that you won't answer such a straight forward question and punt to the wiki & ENAG. It's almost like you refuse to personally support your own model.
In ENAG, in the chapter titled, "Perspective on the Sea", SBR goes to great lengths to describe how when viewing objects over water, like a sinking ship, his 'Law of Perspective' reasoning for why ships go over the horizon doesn't always apply. His 'Law of Perspective' can be found in the preceding chapter, 'Why a Ship's Hull Disappears Before the Mast-Head', aka, the Sinking Ship Effect.
In "Perspective on the Sea" he writes, "If the surface of the sea had no motion or irregularity, or if it were frozen and therefore stationary and uniform, a telescope of sufficient power to magnify at the distance, would at all times restore the hull to sight."
He goes on to write, "Upon the sea the law of perspective is modified because the leading condition, that of stability in the surface or datum line, is changed...because the water is always more or less in motion, not only of progression but of fluctuation and undulation, the "swells" and waves into which the surface is broken, operate to prevent the line of sight from passing absolutely parallel to the horizontal water line."
And he concludes with, "Thus have we ascertained by a simple Zetetic process, regardless of all theories, and irrespective of consequences, that the disappearance of the hull of an outward bound vessel is the natural result of the law of perspective operating on a plane surface, but modified by the mobility of the water; and has logically no actual connection with the doctrine of the earth's rotundity."
Now are we to conclude, from your refusal to give an answer, that the flat earth illusion that is causing 850' of that hill to disappear is due to the
mobility of the water?
The "swells" and waves into which the surface is broken are such that they reach 850' high into the sky from sea level obscuring our view? Or is there some other phenomena at work? Some other illusion, as it were?
You are so quick to call out RET for the use of refraction as an illusion. And here we can only guess upon your non-answer and rely on ENAG/Wiki's two illusions:
1) The atmospheric effects were so great that day that they erased 850' of a hill from view or,
2) An 850' tall "swell" rolled through obscuring our view
Which illusion was it that caused the 850' to disappear?