[Paal Gulli]

"...three gas turbines generate 75,000 horsepower to spin propellers..."

When it's swinging a propeller (airplane or boat), horsepower is meaningless because then it's torque that hauls the mail.

[DUMBGRUNT]

horsepower is meaningless

Not exactly.
If you know one, you can determine the other.

HP has a time element.
Torque does not.

HP = Torque x RPM ÷ 5252

‘Give me a place to stand, and a lever long enough, and I will move the world. ‘ Archimedes

Old Arc would be putting out massive torque/not much HP.