1. Because the weight of the Giants would have to be 345,600 lbs which is quite frankly a physical impossibility today.
Wait, when did this become a discussion on how much giants weight?
Same with "The Monument" The Monument would simply not be sea-worthy if built today with the same design.
So perhaps it's not a ship at all?
However the physics of force has changed about 4 times since then.
Something that you haven't demonstrated thus far.
Therefore a modern man today would have the physical burden of a 24 foot tall man. a 9 foot tall man would have the physical burden of a 36 foot tall man.
The Tallest man alive today is 8ft 3inc.
The Tallest man on record was Robert Wadlow - Wikipedia, the free encyclopedia and he was 8ft 11inches.
Yeah, yeah, none of this is any indication of anything.