Well, you do the math..' Did anyone?

I gave it a shot.

if the creatures are around 25 cm at 2000ft a pencil length with golfball at the end), a conservative 2.5 metres at 4000 (it eats fully grown sharks, but they might be small reef sharks), then every time the depth doubles, the creature is 10 times larger.

At around 38,000 ft I made it around 7 km long, but that could be tentacles (the original draft has the tentacles chase Canton's sppedboat some distance from the ship). The original script also mentions an aerial shot of the cruise liner with a much larger shadow beneath the water, although again it might be a nest of tentacles.

If anyone has a better idea then please share it.