Disagreeing with Sarfati on Two Items

First, the* quote:

At the peak, the Flood covered the highest mountains to 15 cubits deep (about 7 metres or 22.5 feet). The Ark was safe because it sank only about ten cubits into the water—a third of its height.

Two statements here are not in my model of Flood and Ark.

1) He thinks the waterline was 10 cubits up, I think it was 15 cubits up. Or maybe 14 or 14 and a half.
2) He thinks "15 cubits above the very high mountains / the highest mountains" was the peak of the Flood, I think this was what Noah could know of, but not necessarily the peak.

Let's give my reasons.

1) I think a waterline halfway up the ship or in this case non-navigating vessel makes for better stability. (More mundanely, I used that waterline in my calculation of the rolling period.)
2) I think Noah either by prophecy of by calculation of weights could know the waterline was 15 cubits up or 14 and a half, and so he knew this was how much the water was higher than the flat mountain top where he had built the Ark. It does not state that at this moment the water had reached its peak, and need not imply that if "The water was fifteen cubits higher than the mountains which it covered" means "at least 15 cubits" rather than "at most 15 cubits" ...

Genesis 7:20 describes the moment when they cease waiting in an immobile Ark and they feel that the ark starts moving. Or it starts even previous verse. 19 And the waters prevailed beyond measure upon the earth: and all the high mountains under the whole heaven were covered. 20 The water was fifteen cubits higher than the mountains which it covered.

If the waterline was 14 and a half cubits up, Noah calculated one half cubit of water below the bottom of the Ark (there was no keel) was what the Ark needed to float free from the mountain top. Once they were off, they were in deep water, which would not make very turbulent, though certainly big, waves. A thing I and** Sarfati agree on, see his fact box with the kitten in an umbrella holding a paddle. As we do*** on non-existance of Mount Everest before the Flood, see his three sentences after the one I quoted.

The reason I take Genesis 7:19—20 to describe the actual take-off of the Ark is, if the Ark had been floating earlier, it would have risked colliding with the mountains. Now, there is an item where he and I both agree and disagree. Why God sent the Flood. Genesis 6:11 And the earth was corrupted before God, and was filled with iniquity. Now, he, following KJV saying "violence" thinks this refers to a chaos of perpetual warfare, as would inhibit technology by leaving no one able to figure things out. I think the iniquity was closer to Communist China's social credit score./HGL

* The Genesis Flood for kids: The flood peaks
by Jonathan Sarfati | Published in Creation 46(2):32–35, 2024
https://creation.com/the-flood-peaks-cfk

** See also: HGL'S F.B. WRITINGS: He did some answering, though, to others ... · Assorted retorts from yahoo boards and elsewhere: Oceanic Deep Water Waves in Whole Gale : Whitecaps on a Lake, But Bigger

*** See also: Himalayas ... how fast did they rise? · Himalayas, bis ... and Pyrenees · ter · quater · quinquies ... double-checked