Key point: Comparing ships is like comparing apples and oranges, but there are some standards.

For decades, the world’s great powers built countless battleships, not only as a way to win the modern naval battles of the time, but to demonstrate their nation's technical and naval capabilities on the grandest of scales. While the era of the battleship is over, talk still pops up every now and again about a return from retirement, with America’s Iowa-Class battleships being brought back into service--well, at least in our imaginations.

Aircraft carriers, on the other hand, are still the dominant power projection platform of the U.S. and other navies. While many argue the carrier is following a similar path towards obsolescence, thanks to various types of anti-access/area-denial weapons, one can’t deny that the mighty flattop, at least for right now, is still the ultimate non-nuclear way to quickly strike an advisory with devastating force.

But which battleships and carriers were the best? Below, combined for your reading pleasure, are essays authored by James Holmes and Robert Farley, posted several years ago, that tackles this important question.

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Ranking the greatest battleships of all time is a tad easier than ranking naval battles. Both involve comparing apples with oranges. But at least taking the measure of individual men-of-war involves comparing one apple with one orange. That's a compact endeavor relative to sorting through history to discern how seesaw interactions shaped the destinies of peoples and civilizations.

Still, we need some standard for distinguishing between battlewagons. What makes a ship great? It makes sense, first of all, to exclude any ship before the reign of Henry VIII. There was no line-of-battle ship in the modern sense before England's "great sea-king" founded the sail-driven Royal Navy in the 16th century. Galley warfare was quite a different affair from lining up capital ships and pounding away with naval gunnery.

One inescapable chore is to compare ships' technical characteristics. A recent piece over at War Is Boring revisits an old debate among battleship and World War II enthusiasts. Namely, who would've prevailed in a tilt between a U.S. Navy Iowa-class dreadnought and the Imperial Japanese Navy's Yamato? Author Michael Peck restates the common wisdom from when I served in mighty Wisconsin, last of the battleships: it depends on who landed the first blow. Iowas commanded edges in speed and fire control, while Yamato and her sister Musashi outranged us and boasted heavier weight of shot. We would've made out fine had we closed the range before the enemy scored a lucky hit from afar. If not, things may have turned ugly.

Though not in so many words, Peck walks through the basic design features that help qualify a battleship for history's elite -- namely guns, armor, and speed. Makes sense, doesn't it? Offensive punch, defensive resiliency, and speed remain the hallmarks of any surface combatant even in this missile age. Note, however, that asymmetries among combat vessels result in large part from the tradeoffs naval architects must make among desirable attributes.

Only sci-fi lets shipwrights escape such choices. A Death Star of the sea would sport irresistible weaponry, impenetrable armor, and engines able to drive the vessel at breakneck speed. But again, you can't have everything in the real world. Weight is a huge challenge. A battleship loaded down with the biggest guns and thickest armor would waddle from place to place. It would make itself an easy target for nimbler opponents or let them run away. On the other hand, assigning guns and speed top priority works against rugged sides. A ship that's fleet of foot but lightly armored exposes its innards and crew to enemy gunfire. And so forth. Different navies have different philosophies about tradeoffs. Hence the mismatches between Yamato and Iowa along certain parameters. Thus has it always been when fighting ships square off.

But a battleship is more than a machine. Machines neither rule the waves nor lose out in contests for mastery. People do. People ply the seas, and ideas about shiphandling and tactics guide their combat endeavors. Great Britain's Royal Navy triumphed repeatedly during the age of sail. Its success owed less to superior materiel -- adversaries such as France and the United States sometimes fielded better ships -- than to prolonged voyages that raised seamanship and gunnery to a high art. Indeed, a friend likes to joke that the 18th century's finest warship was a French 74-gun ship captured -- and crewed -- by Royal Navy mariners. The best hardware meets the best software.

That's why in the end, debating Jane's Fighting Ships entries -- lists of statistics -- for Iowa, Yamato, and their brethren from other times and places fails to satisfy. What looks like the best ship on paper may not win. A ship need not outmatch its opponents by every technical measure. It needs to be good enough. That is, it must match up well enough to give an entrepreneurial crew, mindful of the tactical surroundings, a reasonable chance to win. The greatest battleship thus numbers among the foremost vessels of its age by material measures, and is handled by masterful seamen.

But adding the human factor to the mix still isn't enough. There's an element of opportunity, of sheer chance. True greatness comes when ship and crew find themselves in the right place at the right time to make history. A battleship's name becomes legend if it helps win a grand victory, loses in dramatic fashion, or perhaps accomplishes some landmark diplomatic feat. A vessel favored (or damned) by fortune, furthermore, becomes a strategic compass rose. It becomes part of the intellectual fund on which future generations draw when making maritime strategy. It's an artifact of history that helps make history.

So we arrive at one guy's gauge for a vessel's worth: strong ship, iron men, historical consequence. In effect, then, I define greatest as most iconic. Herewith, my list of history's five most iconic battleships, in ascending order:

Bismarck:

The German Navy's Bismarck lived a short life that supplies the stuff of literature to this day. Widely considered the most capable battleship in the Atlantic during World War II, Bismarck sank the battlecruiser HMS Hood, pride of the Royal Navy, with a single round from her main battery. On the other hand, the leadership's martial spirit proved brittle when the going got tough. In fact, it shattered at the first sharp rap. As commanders' resolve went, so went the crew's.

Notes Bernard Brodie, the dreadnought underwent an "extreme oscillation" in mood. Exaltation stoked by the encounter with Hood gave way to despair following a minor torpedo strike from a British warplane. Admiral Günther Lütjens, the senior officer on board, gathered Bismarck crewmen after the air attack and "implored them to meet death in a fashion becoming to good Nazis." A great coach Lütjens was not. The result? An "abysmally poor showing" in the final showdown with HMS Rodney, King George V, and their entourage. One turret crew fled their guns. Turret officers reportedly kept another on station only at gunpoint. Marksmanship and the guns' rate of fire -- key determinants of victory in gunnery duels -- suffered badly.

In short, Bismarck turned out to be a bologna flask (hat tip: Clausewitz), an outwardly tough vessel that shatters at the slightest tap from within. In 1939 Grand Admiral Erich Raeder lamented that the German surface fleet, flung into battle long before it matured, could do little more than "die with honor." Raeder was righter than he knew. Bismarck's death furnishes a parable that captivates navalists decades hence. How would things have turned out had the battlewagon's human factor proved less fragile? We'll never know. Doubtless her measure of honor would be bigger.

Yamato:

As noted at the outset, Yamato was an imposing craft by any standard. She displaced more than any battleship in history, as much as an early supercarrier, and bore the heaviest armament. Her mammoth 18-inch guns could sling 3,200-lb. projectiles some 25 nautical miles. Armor was over two feet thick in places. Among the three attributes of warship design, then, Yamato's designers clearly prized offensive and defensive strength over speed. The dreadnought could steam at 27 knots, not bad for a vessel of her proportions. But that was markedly slower than the 33 knots attainable by U.S. fast battleships.

Like Bismarck, Yamato is remembered mainly for falling short of her promise. She provides another cautionary tale about human fallibility. At Leyte Gulf in October 1944, a task force centered on Yamato bore down on the transports that had ferried General Douglas MacArthur's landing force ashore on Leyte, and on the sparse force of light aircraft carriers, destroyers, and destroyer escorts guarding the transports from seaward assault.

Next ensued the immortal charge of the tin-can sailors. The outclassed American ships charged Yamato and her retinue. Like Lütjens, Admiral Takeo Kurita, the task-force commander, appeared to wilt under less-than-dire circumstances. Historians still argue about whether he mistook Taffy 3, the U.S. Navy contingent, for a far stronger force; lost his nerve; or simply saw little point in sacrificing his ships and men. Whatever the case, Kurita ordered his fleet to turn back -- leaving MacArthur's expeditionary force mostly unmolested from the sea.