When Nelson made that statement, ships did not carry guns powerful enough to readily knock down fortress walls, while forts had guns much bigger than a ship could carry.
I wonder what his thoughts would be upon seeing a WW2 battle ship with 16" guns able to toss a 1,000 pound explosive shell several miles?
Go to Ft. Pulaski outside Savanah GA to see the effects circa 1863 rifled cannon had against the kinds of forts Nelson described.
Then think of what a single broadside of 16” superheavy armor piercing shells travelling at Mach 2 after being fired from an Iowa Class BB would have. Followed up by a broadside of HE shells.
THEN think of what a dozen 2000lb JDAM penetrators dropped from six F/A-18s operating from a carrier several hundred miles away (if not more, with inflight refueling) would have.
2,700 lb shell over 20 miles. Dad was a (Iowa class) battleship officer.
Sorry, couldn't help it.