Why did the USS Maine explode?

Few U.S. ships are as well remembered as the battleship Maine. Unlike Constitution, Monitor, or Enterprise, though, the ship is not famous for its wartime record, long career, or remarkable innovation. Rather, Maine is remembered for exploding in Havana harbor on 15 February 1898. The death of 260 crewmen and officers would be tragedy enough, but the explosion also sparked the Spanish-American War and all of its consequences, including the U.S. colonization of Puerto Rico, Guam, and the Philippines. At the 125th anniversary of this shipboard catastrophe, it is worth reviewing why Maine blew up.

The cause of Maine’s explosion has been hotly debated by press, politicians, naval experts, scientists, historians, and hobbyists for well over a century.[1] Many theories have been proposed to explain the warship’s destruction, ranging from the ludicrous[2] to the plausible. While structural failure, torpedo malfunction, boiler problems, sabotage, and many other explanations have been advanced, the debate generally revolves around two potential causes. The first is that a mine punctured Maine’s hull and sparked a catastrophic explosion in the ship’s magazine. The second is that an accident, most likely a coal bunker fire, set off the magazine. While the available physical and historical evidence overwhelmingly indicate Maine was destroyed by an accident inside the ship, let’s look at how this evidence was collected before evaluating the two main explanations.

The U.S. Navy investigated the sinking of Maine on three separate occasions. The first investigation started on 21 February, less than a week after the battleship sank. A Court of Inquiry headed by Captain William T. Sampson explored the wreckage and collected eyewitness testimony that gives valuable insight into the human toll of the disaster. However, the investigation was handicapped by poor diving technology and extremely tense U.S.-Spanish relations.[3] The Sampson Board concluded on 21 March that Maine had been destroyed by a mine placed near Frame 18. The United States declared war on Spain 35 days later.[4] In 1910, the U.S. Army Corps of Engineers built a cofferdam around Maine to recover bodies and remove the wreck from Havana harbor, which enabled the Navy to launch a second, more detailed investigation of the Maine. A Court of Inquiry led by Admiral Charles Vreeland took advantage of the now exposed ship to photograph the wreckage and explore the structural damage. It concluded that a mine placed between frames 28 and 31 destroyed the battleship.[5] Despite Vreeland’s conclusions, debates about Maine continued for decades, prompting Admiral Hyman Rickover to launch his own investigation in 1974. He contracted Ib S. Hansen and Robert S. Price, both of whom had years of experience analyzing ship damage caused by underwater explosions. Hansen and Price examined the photos taken by the Vreeland investigation. They in turn concluded that Maine had not been sunk by a mine but had been destroyed instead by an internal explosion, most likely sparked by a coal fire.[6] The Spanish government,[7] National Geographic,[8] Discovery Channel,[9] and others have also investigated Maine’s loss, but serious work on the topic to this day relies on the evidence and analysis of Sampson, Vreeland, and Rickover.

The Sampson and Vreeland investigations concluded that Maine was destroyed by an underwater mine. While this explanation has a certain appeal, the physical state of the ship makes it effectively impossible. Proponents of the mine theory point to two main pieces of evidence.[10] First, Maine’s keel ended up bent strangely, in the form of an upside-down V. The Sampson-led court of inquiry argued that this could have only been caused by a mine forcing the keel upward.[11] However, the keel had no physical blast damage, nor was the rest of the ship distorted in a way consistent with a large underwater explosion. Any mine capable of forcing the keel up into this shape would have lifted the ship out of the water, which no witnesses saw.[12] Second, Vreeland’s board found part of the hull, designated Section 1, which was folded up into the interior of the ship. The board argued this fold was caused by an external explosion forcing the section in. However, like the keel, Section 1 had no scarring or blast damage consistent with a mine.[13] The fold is also wrong. According to the mine theory, a mine blew a hole in the hull and then detonated the ship’s 6-inch shell magazine. If that were the case, Section 1 would have been smashed flat against the outer hull of the ship by the magazine explosion. Instead, Section 1 was simply folded over and scarred on the inside, but not outside.[14]

If the physical evidence for a mine is lacking, the historical evidence is non-existent. A mine would have had to have been placed by one or more persons. There are plenty of mine conspiracy theories assigning blame to either to the Spanish government, fanatical Spanish officers loyal to General Valeriano “The Butcher” Weyler, Cuban insurrectionists trying to spark U.S. intervention on their behalf against Spain, or reporters trying to sell more papers.[15] Simply put, no credible evidence of any such conspiracy has come to light in the last 125 years.[16] Even Sampson and Vreeland never blamed any specific party for placing the mine they claimed had destroyed the ship.[17] While we lack conspirators that hardly matters as the technical difficulties in placing a mine in Havana harbor were all but insurmountable. If the mine was placed before the ship arrived, the Spanish garrison would have been mining their own commercial harbor at great risk to their own shipping. If the mine was placed by fanatics or insurrectionists when Maine was at anchor, it would have been very difficult to set up under the watchful eyes of suspicious American sailors and Marines. Moreover, mines in that era were a problematic choice for anyone determined to sink the American battleship, owing to difficulties of fuses, placement, weapon endurance, and triggering.[18] While it is impossible to prove a negative, the thought that an undetected, untraceable mine destroyed Maine while leaving damage to the ship’s hull unlike any other recorded underwater explosion, without any evidence of any perpetrators, is difficult to accept.  

If not a mine, than what? The wreckage of Maine clearly indicates that the initial explosion occurred in the 6-inch shell magazine. Damage to the ship radiates out from there. Hansen and Price point out that any number of causes may have detonated the 6-inch magazine, but the wreckage simply does not support an external cause. They posited that a coal fire in bunker A-16 could have gone undetected long enough to heat up some 6-inch shells. Warming up these shells would have been easy, since there was only a 1/8 inch thick steel bulkhead between the coal and the shells. The shells in turn exploded, detonating the rest of the magazine.[19] While there is no direct proof in support of this theory, it is the explanation that makes the most sense with the available evidence, including contemporary documentation that spontaneous coal fires were common on ships of the era. The main objection to the coal bunker explanation is that the crew would have detected a coal fire.[20] However, the Sampson court of inquiry found that no one had inspected the relevant bunker or magazine since early in the morning, leaving almost 12 hours for a fire to smolder undetected. This was more than enough time to heat up adjacent shells.[21]

If the ship was blown up by an accident onboard, how do we explain Section 1 and the keel at Frame 18? When the magazine exploded, the hull burst out in many places. The ship sank rapidly, though, as water rushed into these new holes. The combination of moving water and the great mass of the ship above can easily bend steel and is the most likely cause of Section 1 folding back into the ship. After the explosion, the entire front section of the ship buckled, bent, and twisted, being connected to the aft section by only the keel. As a result, the keel ended up bent upward. While this can seem strange, it is consistent with underwater damage observed in World War II.[22] We will never know for sure what sparked the magazine explosion that destroyed Maine. We can be sure, though, that the ship was destroyed by an internal explosion, likely caused by accident.

Perhaps one of the reasons the Maine mystery has continued to linger to this day, is that in the wake of the ship’s loss, the United States, and the Navy had little incentive to blame an accident for the disaster. First, if Spain, or Cubans, or newspapermen really had blown up the ship it would have justified the war the United States fought in revenge. The Spanish-American War was the United States’ first real step onto the world stage and turned the country into a global imperial power, a goal desired by American navalists both in and out of government. America’s later record in the Philippines and her other colonies is justifiably open to severe criticism. Seizing those colonies over a shipboard accident rather than an actual attack further complicates the American imperial project.[23]

Second, Maine mattered to the Navy. The turn of the century was also the debut of the modern U.S. fleet. The “New Steel Navy” represented an incredible leap in American military reach and potential. If Maine blew up due to a design flaw, than it revealed deep problems in American shipbuilding and construction and could harm recruitment and Congressional funding. It also vividly illustrated the risks that came with the Navy’s new ordnance, engines, and fuel. When he was Assistant Secretary of the Navy, Theodore Roosevelt attacked the suggestion that Maine exploded due to an accident as taking “the Spanish side” and feared that it might discredit further naval construction.[24] Likewise, Charles Sigsbee, captain of Maine at the time of its loss, had an obvious motivation to blame Spain rather than his crew or his own actions for the explosion. An accident on Maine could have sunk his career, or public support for the Navy in general.[25]

Maine was lost to an onboard explosion, probably when a spontaneous coal fire detonated the 6-inch shell magazine. Spain, Cuban insurrectionaries, and yellow journalists had no part in destroying it. It did not justify the war and imperial project that came as a result and it revealed deep flaws in the structure and design of the new U.S. fleet. The Spanish-American War papered over these truths for a time, as American ships sank Spanish fleets at Manila and Santiago and recruits rallied to the flag with calls to “Remember the Maine.” It is to Admiral Rickover’s great credit that he and his team used Navy funds and credibility to expose the truth. The 260 men who lost their lives onboard and in the weeks that followed were not martyrs killed by Spain. They were the victims of a terrible accident, as were the Americans, Spanish, Cubans, Puerto Ricans and Filipinos killed or injured in the Spanish-American War. It dishonors their memory to teach otherwise.