As Mahan and Theodore Roosevelt contended in their histories of the conflict, the early republic erred grievously by failing to construct a battle fleet of, say, twenty 74-gun capital ships able to command America’s near seas. Though inferior in numbers to the Royal Navy in overall numbers, such a fleet could have cut ties between the British Isles and the Caribbean—imperiling British interests there, and thus perhaps deterring war altogether. Globally inferior—locally superior.

It’s crucial to remember and learn from defeat. People and the institutions they comprise commonly tout past triumphs while soft pedaling setbacks. That’s natural, isn’t it? Winning is the hallmark of a successful team, losing a hateful thing. And yet debacles oftentimes have their uses. They supply a better reality check than victories. Defeat clears the mind, putting the institution on “death ground”—in other words, compelling it to either adapt or die. Nimble institutions prosper.

Winning, on the other hand, can dull the mind—reaffirming habits and methods that may prove ill-suited when the world changes around us. As philosophers say, past success and the timber of humanity predispose individuals and groups to keep doing what worked last time. Or as the old adage goes: if it ain’t broke, don’t fix it. Problem is, we have a habit of discovering it is broke at the worst possible time—when fixing things gets dicey.

Despite its record of victory, the America’s navy is far from exempt from the universal proclivity to celebrate success. Failure? Fuggedaboutit. Now, we shouldn’t wallow in long-ago defeats: strategist Bernard Brodie cautions that major fleet duels are “few and far between even as centuries are reckoned.” When sample size = small, it’s best not to read too much into the results of any individual encounter. Change a variable or two and you may get an entirely different outcome.

Nevertheless, it’s important to remain mindful of the low points—if only to ward off hubris while reminding seafarers that institutions must keep up with changing times or find themselves irrelevant. In that spirit, what follows is my list of America’s Five Worst Naval Defeats. These being the dog days of summer, with the Narragansett Bay bathed in hazy sunshine, I’m casual about what constitutes defeat. Strategic, operational, tactical: all losses are fair game.

Now, losing a war is worse than losing a tactical action. The former ranks higher, but both varieties of ignominy make the list. The tactical defeats presented here, however, meet Carl von Clausewitz’s standard for “operations that have direct political repercussions”—namely outsized, negative, self-defeating repercussions. Such thrashings brought disrepute on the navy or the flag, damaged America’s diplomatic standing vis-à-vis other nations, or biased the political scene toward future conflict.

Or all of the above. One defeat that’s conspicuously absent from this list is Pearl Harbor. The battle line was moored around Ford Island on December 7, not underway. Stationary fleets accomplish little in combat. Pearl Harbor qualifies as a naval victory for Japan. Indeed, it was a masterwork. From the American standpoint, though, it was less a naval defeat than a failure to mount a joint offshore defense of military installations on Oahu. Plenty of blame to share.

December 7 will live in infamy, to be sure. But it constituted an across-the-board collapse for the U.S. Navy … and Army, and Army Air Forces. These forces were all entrusted with holding Oahu. That puts Pearl Harbor in an altogether different category. With that proviso, onward.

Bainbridge at Algiers:

Minor tactical failures can beget major humiliations for the individual, the service, and the flag. Take for instance the strange case of Captain William Bainbridge. In 1800 the skipper of the frigate George Washington neglected a time-honored axiom of naval warfare, namely that a ship’s a fool to fight a fort. Fortresses have lots of space, and thus heavier guns, greater striking range, and bigger ammunition magazines. Seldom do ships match up well.

Ordered to carry tribute to the dey of Algiers, George Washington stood in under the guns of the fort. Outgunned, Bainbridge was ordered to carry gifts, an ambassador, slaves, harem women, and a menagerie of animals to the Ottoman Porte in Constantinople—and to do all of this while flying the flag of Algiers. Otherwise, the dey’s emissaries let it be known, the frigate would be smashed to splinters, its crew enslaved.

The upside to this outrage: President Thomas Jefferson resolved to act against the Barbary States by naval force rather than pay tribute for temporary maritime freedom. Lesson: minor tactical miscues can spawn major diplomatic headaches. Mariners, then, must think of themselves as naval diplomats as well as sea warriors—and try to foresee the strategic and political import of their actions, missteps, and foibles.

Ironbottom Sound:

The Battle of Savo Island (August 9, 1942) was—as Samuel Eliot Morison puts it—“probably the worst defeat ever inflicted on the United States Navy in a fair fight.” In brief, U.S. Marine expeditionary forces had landed safely on Guadalcanal and Tulagi, in the Solomon Islands, in order to evict Japanese forces that were constructing an airfield from which warbirds could cut the sea and air lanes connecting North America with Australia.

Unlike the U.S. Navy of 1942, the Imperial Japanese Navy (IJN) excelled at nighttime fighting. Admiral Gunichi Mikawa brought a surface task group down the “Slot” from Rabaul, at the far end of the Solomons chain, on the night of August 8 to attack the American ships unloading on Guadalcanal. U.S. commanders had dispersed their cruisers and destroyers into four detachments in an effort to guard the entryways into the Sound that lay between Guadalcanal, Savo, and Florida islands.

Though perhaps strong in the aggregate, fragmenting a force along a picket line leaves it weak at any given point along the line. Accordingly, Mikawa’s concentrated squadron rampaged through the Allied fleet that night, leaving the wreckage of four heavy cruisers (of six present) strewn across the seafloor, not to mention two destroyers damaged and 1,077 sailors dead. Hence the nickname Ironbottom Sound.

Morison observes that Savo Island had a silver lining. Fate intervened. The transports remained unscathed after Mikawa failed to press his attack, for fear of suffering a daytime air attack from U.S. carriers. The IJN fleet hightailed it for home after pummeling the Allied combatants. The U.S. Navy learned to take its opponent seriously, especially at night; reformed its communications and air-surveillance methods to supply early warning of future assaults; and refined its firefighting equipment and techniques to keep battle damage in check.

Still, losing that many ships and lives—and placing the U.S. Marines’ mission in jeopardy—constituted a painful way to learn to respect a serious enemy while remaining cognizant of the surroundings.

Confederate Raiding in Civil War:

Yes, the Union Navy imposed a stifling blockade on the Confederacy, and yes, wresting control of rivers from the Confederates helped slice-and-dice the breakaway republic. As Alfred Thayer Mahan notes, Southerners “admitted their enemies to their hearts” by allowing the Union to wrest away control of internal waterways like the Mississippi. “Never,” adds Mahan, “did sea power play a greater or a more decisive part” than in the struggle for North America.

That doesn’t mean the Confederacy was impotent at sea. Raiders fitted out in Great Britain and armed in the Azores wrought enormous damage to the Union merchant and whaling fleets. Raiders like CSS Alabama, Florida, and Shenandoah burned or captured and ransomed 225 merchantmen and whalers during the war, along with another 27 dispatched by privateers. Their exploits diverted Union men-of-war from blockade duty, drove up insurance rates, and prompted shippers to move most American-flagged vessels into foreign registry to escape the Southern predators.

In short, Florida, Alabama, and their sisters did lasting damage to U.S. commercial shipping—and thus to one of Mahan’s three “pillars” of sea power. The havoc they sowed vindicates Mahan’s observation that guerre de course constitutes “a most important secondary operation” in sea warfare. Raiding enemy shipping may not decide the outcomes of wars, but it contributes at the margins. And as the Civil War shows, the weak can impose frightful costs on the strong—even in a losing cause.

The damage to the U.S. marine industry, one of the lineaments of American sea power, entitles Civil War guerre de course to a place in the United States’ annals of naval defeat.

War of Independence:

If Savo Island was America’s worst pasting in a fair fight, the Revolutionary War was its worst loss in an unfair fight. That it was unfair is excusable. After all, the Continental armed forces were invented under fire—stressful circumstances for raising, training, and equipping any institution. The struggle for independence demonstrates that a combatant needs a navy of its own to beat an enemy that possesses a great fleet. It also demonstrates that it’s easier to improvise an army than a navy.

Sure, Continental seamen had their moments. John Paul Jones remains a folk hero to the U.S. Navy, interred beneath the Naval Academy chapel. Jones, furthermore, is celebrated in such oddball locales as the battleship Mikasa museum in Yokosuka, whose curators style him the equal of Lord Horatio Nelson and Admiral Heihachirō Tōgō, Japan’s greatest naval hero. But individual derring-do shouldn’t obscure the fact that the American colonies had to borrow a fleet, that of France, to prevail in the endgame at Yorktown—and thus achieve their independence.